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Why Bach is the Greatest of all Time...in under 5 min!

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How Vivaldi took the world by storm.. sun, snow, and rain. Ep19: Antonio Vivaldi - The Four Seasons

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Read through the questions with family or friends for practice with format and content.

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Read through the questions with family or friends for practice with format and content.

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Read through the questions with family or friends for practice with format and content.

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Read through the questions with family or friends for practice with format and content.

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Read through the questions with family or friends for practice with format and content.

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Print. Complete. Quiz your teammates. Have people quiz you. Write questions like these on topics you think sound useful. Show Mrs. Wagner for a quick treat. Dominate!

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IWMS Scholastic Bowl Team Info for PARENTS & FAMILIES

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Why the Appalachians Contain Some of the Oldest Fossils on Earth

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Special End-of-Year 2025 News Quiz for Students

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See what you remember about this extraordinary year by taking our special 2025 news quiz.

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A new pope, political shake-ups and celebs in space: The 2025-in-review news quiz

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How much do you remember about pranks, pardons and pills?

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Artists have reimagined the myth of Orpheus and Eurydice many times over the millennia. Here are a few notable examples:

Orfeo,a 1607 opera by the Italian composer Claudio Monteverdi, is one of the first operas ever written and the oldest that is still regularly performed. Listen to it here.

The composers Gluck, Haydn, Liszt, and Stravinsky also wrote music inspired by Orpheus and Eurydice. Listening to their different compositions allows you to compare how different artists from different periods in history have imagined the mythical music of Orpheus, which was so beautiful it (almost) overcame death.
a 2003 play by the playwright Sarah Ruhl, imagines the story from Eurydice's perspective.
is a 1950 film by the French filmmaker and writer Jean Cocteau; the second part in his trilogy inspired by the Orpheus and Eurydice myth.

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The tragic myth of Orpheus and Eurydice - Brendan Pelsue

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The marriage of Orpheus, the greatest of all poets and musicians, to Eurydice, a wood nymph, was heralded as the perfect union. Anyone could tell the couple was deeply in love. So when their wedding ceremony ended in Eurydice's untimely death, Orpheus had no choice but to venture into the underworld to try to reclaim his lost love.

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Why should you read Charles Dickens? - Iseult Gillespie

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The starving orphan seeking a second helping of gruel. The spinster wasting away in her tattered wedding dress. The stone-hearted miser plagued by the ghost of Christmas past. More than a century after his death, these remain recognizable figures from the work of Charles Dickens. But what are t…

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To learn more about New Horizons and its journey through space, click here.

In this podcast episode of Gravity Assist, Jim Green speaks with the lesson's educator, Alan Stern, who was the New Horizons Principal Investigator.

This editorial in the Washington Post, co-written by David Grinspoon and the educator, explains why Pluto should be a planet.

Want to find out more about the equipment that captured vital information on Pluto? Click here to see a picture of the Ralph instrument and here to see REX.

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The journey to Pluto, the farthest world ever explored - Alan Stern

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As of 1989, mankind had successfully sent craft to every known planet in the solar system except one: Pluto. Located in an mysterious region called the Kuiper Belt, Pluto is a scientific goldmine, and could hold clues to the formation of our solar system.

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How squids outsmart their predators - Carly Anne York

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There are about 500 species of squid, and they live in all the world’s oceans, making them a reliable food source for whales, dolphins, sharks, seabirds, fish - and even other squid. As a result, the squid’s most extraordinary adaptations are those that have evolved to help them thwart these predato…

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Happy Cinco de Mayo! We all love to celebrate on the 5th of May but not many people know the actual history behind this day. Lifehacker explains the history behind the holiday.

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Scientists have been studying the physiology and behavior of hibernation for decades. For these studies, researchers collect different types of data, including body mass variations throughout the year, as well as dietary and locomotion adaptations during autumn fattening. They also catalogue physiological changes, such as body temperature, by collecting temperature readings from the abdominal cavity or skin. Scientists also use closed chambers, known as respirometers, to measure the exchange rate of oxygen and carbon dioxide; this reading can identify an animal's respiration and their metabolic rate. Typically, these studies are done in a laboratory under carefully controlled settings, such as identical diets or feeding regimens.

With the introduction of smaller data loggers to record body temperature-and with better technology to track animals in the wild using radio transmitters-scientists have begun to study animals in their natural habitats. What they found was that more animals than originally expected were using some form of torpor to escape harsh environmental conditions. In 2004, Kathrin Dausmann and her colleagues measured the body temperature profiles of fat-tailed dwarf lemurs in Kirindy Forest, Madagascar. This was the first time that hibernation was documented in a primate. Dwarf lemurs are found in various parts of Madagascar and, depending on where they are found, can hibernate in tree holes (in the dry, deciduous forests in the west) or in underground burrows (in the high-altitude rainforests in the central-east). They have been studied in both locales, as well as at the Duke Lemur Center, which is the only place they are found in captivity.

To learn more about dwarf lemur hibernation, check out the educator's article in Scientific American. You can also read her personal blog about field work in Madagascar.

Interested in the possibility of human hibernation? Click here to listen to the educator's interview with BBC for a Radio 4 program.

Dwarf lemurs, like most hibernators, are small-bodied animals that lose heat to the environment quickly. This is because they have a large surface area to volume ratio. Think of your hand on a cold winter's day. Your hand, if it's balled up nice and tight, will stay warmer longer. However, if you flatten your hand, it gets colder much quicker. While the volume of your hand stays the same in both instances, the surface area when it's flattened becomes much greater, leaving more of your hand exposed.

The only exception to the small-body-size rule, as far as scientists know, are bears. However, bears break other rules, too! For example, during torpor, bears only reduce their body temperature a few degrees below their normal temperatures. The body temperatures of other hibernators will drop to just around their surrounding temperatures, which can sometimes be close to 0°C. Bears will also give birth and lactate, which is shown in more detail in this BBC video.

This great article from Science News for Students is full of other great information on hibernation.

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How does hibernation work? - Sheena Faherty

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The Arctic Ground Squirrel hibernates by burrowing under the permafrost and slipping into a state of suspended animation. The female black bear can give birth while she hibernates. The fat-tailed dwarf lemur prepares to hibernate by storing its fat reserves in its tail - doubling its body weight.

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Disclaimer: This video contains curse words and some strong language which may be unsuitable for younger audiences. Though the country may appear small, few nations on Earth have had a more colorful history than Japan. Bill Wurtz explains Japan's rich history.

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Interested in learning more about Roman legionaries? Check out this book or this one. G.R. Watson also delves into military life for both Greek and Roman soldiers in The Roman Soldier. This video shows how they prepared for battle, including what they wore and the equipment they carried.

What were the differences between a Roman soldier and a Germanic warrior? Read this book by Lindsay Powell.

Want to explore the possibilities of life in a Roman legion? Rosemary Sutcliff's The Eagle is a historical fiction series that navigates the adventures and dangers of being a young soldier.

Check out this course on being a Roman Soldier in The Other Side of History: Daily Life in the Ancient World, created by the educator.

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A day in the life of a Roman soldier - Robert Garland

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The year is 15 CE, and the Roman Empire is prospering. Most of the credit will go to the emperor, but this success wouldn't have been possible without loyal soldiers like Servius Felix. Robert Garland illuminates what life was like for a solider in the Roman army.

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Dr. Marie Curie transformed science and society with her discoveries. Her scientific partnership with Pierre Curie and the story of their heroic efforts that led to the discovery of polonium and radium are legendary. Despite her scientific contributions and winning her first Nobel prize in 1903, as a woman and an immigrant, she was not elected to the French Academy of Sciences in 1911. She also faced vicious and xenophobic attacks from the press for an alleged affair with the scientist Paul Langevin. That year she won her second Nobel prize, but she never again applied for membership in the Academy. Read her Nobel lecture here.

When war broke out in 1914, Dr. Curie and her daughter Irène helped to equip vans with X-ray technology for medical use, and she herself drove one of the vans, which soldiers called ' petite Curies'. After the war, she worked for the rest of her career at her Radium Institute, which became a world-leading centre under her leadership. She visited the US twice and in 1921 she received a gift 1 gram of radium, worth a small fortune, from US President Warren Harding on behalf of the women of America. Watch a video of the event here. Dr. Curie's studies of radioactivity laid the foundations for modern cancer treatment.

The Curie family was truly distinguished. Not only were Pierre and Marie Curie Nobel laureates, but their daughter Irène and son-in-law Frédéric Joliot also shared a Nobel Prize in chemistry in 1935 for their synthesis of new radioactive elements. Their younger daughter Eve wrote a bestselling book about her mother's extraordinary life. A movie based on the book was released in 1943, but for a slice of real history, watch Dr. Curie at work in her lab here.

Find out more about the elements Radium and Polonium in these TED Ed lessons about these elements.

Font (typeface) used in the animation: Neacademia by Rosetta Type.

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The genius of Marie Curie - Shohini Ghose

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Marie Skłodowska Curie's revolutionary research laid the groundwork for our understanding of physics and chemistry, blazing trails in oncology, technology, medicine, and nuclear physics, to name a few. But what did she actually do? Shohini Ghose expounds on some of Marie Skłodowska Curie's most revolutionary discoveries.

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Let's Begin...

In 1815, Lord Byron proposed a challenge to a few literary guests he had gathered in his house on Lake Geneva: Who could write the most chilling ghost story? This question sparked an idea in eighteen-year-old Mary Shelley who, over the next few months, crafted the story of "Frankenstein." Iseult Gillespie shares everything you need to know to read Mary Shelley's classic novel.

Create and share a new lesson based on this one.

About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here "

Meet The Creators

Educator Iseult Gillespie

Director Silvia Prietov

Animator Silvia Prietov, William Cifuentes

Producer Silvia Prietov

Art Director Silvia Prietov

Storyboard Artist Silvia Prietov

Designer Andrés Felipe Landazábal

Character Designer Andrés Felipe Landazábal

Layout Artist Andrés Felipe Landazábal

Compositor Julian Andrés Sánchez

Sound Designer Andrés Silva, Alejandro Uribe-Holgin

Composer Manuel José Gordillo

Associate Producer Jessica Ruby

Content Producer Gerta Xhelo

Editorial Producer Alex Rosenthal

Narrator Susan Zimmerman

See more creators

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Everything you need to know to read "Frankenstein" - Iseult Gillespie

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In 1815, Lord Byron proposed a challenge to a few literary guests he had gathered in his house on Lake Geneva: Who could write the most chilling ghost story? This question sparked an idea in eighteen-year-old Mary Shelley who, over the next few months, crafted the story of "Frankenstein."

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Nelson Mandela is known as a world humanitarian, anti-apartheid activist, and former South African president. Check out this short biography of Nelson Mandela from the Biography Channel to learn more.

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How do carbohydrates impact your health? - Richard J. Wood

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The things we eat and drink on a daily basis can impact our health in big ways. Too many carbohydrates, for instance, can lead to insulin resistance, which is a major contributor to cardiovascular disease and Type 2 Diabetes. But what are carbs, exactly? And what do they do to our bodies? Richard…

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Interested in the Ancient Olympic Games and the mythology behind them? Click here to find out more! Do chariot racing, the pankration, and twenty competitors on one running track at once sound challenging? Visit this site to find out more about the competitions, spirit of the ancient Olympics, and stories of the competitors.

For all things Olympic go to Olympic.org, and take a look at the featured athletes, youth development and future Olympic cities. Which city will host the next Olympic games in 2016? Read about how the next Olympic city will be chosen and the process that goes along with it here. After all the festivities and competitions are done, see " What Becomes of Olympic Stadiums." Interested in following Olympic news on social media? Visit Ever wonder about the meaning behind the Olympic Symbols? What is the meaning of the five rings, the flame, and the motto "Citius, Altius, Fortius." Read this and find out their meanings. Interested in Olympic Medals? Are they really made of Gold, Silver and Bronze? Learn the truth here!

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The ancient origins of the Olympics - Armand D'Angour

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Thousands of years in the making, the Olympics began as part of a religious festival honoring the Greek god Zeus in the rural Greek town of Olympia. But how did it become the greatest show of sporting excellence on earth? Armand D'Angour explains the evolution of the Olympics.

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Cicadas: The dormant army beneath your feet - Rose Eveleth

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Every 13 or 17 years, billions of cicadas emerge from the ground to molt, mate and die. Adult cicadas only live a few weeks above ground, but you’d be hard pressed to ignore them -- they are extremely loud! Rose Eveleth explains everything you need to know about these noisy insects, admitting that there’s still some things we just don’t understand.

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The Camelot Project at the University of Rochester contains a wealth of information on all aspects of the Arthurian legends. It even contains a bibliography devoted to articles and books that discuss the question of Arthur's historicity.

The New Arthurian Encyclopedia, edited by Norris J. Lacy, includes articles on the question of Arthur's historicity.

The Oxford Guide to Arthurian Literature and Legend, written by the educator, contains a section on historical literature that discusses everything from the earliest accounts of Arthur and his battles to historical novels.

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Is there any truth to the King Arthur legends? - Alan Lupack

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King Arthur has risen again and again in our collective imagination, along with his retinue of knights, Guinevere, the Round Table, Camelot, and of course Excalibur. But where do these stories come from, and is there any truth to them? Alan Lupack traces the evolution of King Arthur.

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Read more on Sisyphus in Greek mythology and the cultural significance of his myth during the Renaissance.

And be sure to check out Albert Camus's classic essay on Sisyphus as a modern absurd hero.

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Sisyphus was both a clever ruler who made his city prosperous, and a devious tyrant who seduced his niece and killed visitors to show off his power. While his violation of the sacred hospitality tradition greatly angered the gods, it was Sisyphus' reckless confidence that proved to be his downfall -- resulting in Zeus condemning him for all eternity.

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Trauma is any negative life event in which the brain perceives a real sense of danger, horror, and helplessness. PTSD occurs when people are directly exposed to, repeatedly exposed to, or witness horrific events, such as death, abuse, domestic violence, or war. During these events, the body's stress response kicks into overdrive. Studies show that women are more likely to experience sexual abuse as children, whereas men are more likely to experience physical assault or witness death.

A person's PTSD symptoms may prove indiscernible to others. When people are reliving their trauma, they sometimes stare off into space as if they are watching a movie. This is known as the "thousand-yard stare" and is typically the only observable symptom.

Prompted by the autonomic nervous system (ANS), the brain sends alert signals to prepare the body to ward off danger. This survival instinct reaction is called the hyperarousal acute stress response, or, as it's more commonly called, the fight-flight-freeze response. This reduces overall brain functioning. PTSD is considered an anxiety-based disorder with symptoms that fall into in four categories: intrusive thoughts, like dreams and flashbacks; avoiding reminders of the trauma; negative thoughts and feelings of fear, anger, horror, shame and guilt; and "reactive" symptoms like irritability, self-destructive behaviors, physical outbursts, and difficulty sleeping. Not everyone with PTSD has all of these symptoms, and they tend to vary in form and intensity from person to person. Sometimes symptoms disappear completely and resurface years later when the traumatic event is triggered again by another stimulus. When the symptoms last for more than a month, they are chronic, and diagnosed as PTSD.

The adaptability of the hypothalamic-pituitary-adrenal (HPA) axis plays a key role in how our stress response engages when we're exposed to a traumatic event. When the hypothalamus sends a message to the ANS, the bloodstream is flooded with several different stress hormones, such as cortisol. These hormones also release extremely high levels of natural opiates, which temporarily mask pain. A person may feel as if the event is occurring right now-their brains re-experience the traumatic event through surges of energy and intrusive thoughts. Severe anxiety can result as they experience a heightened sensitivity to potential dangers. Researchers found that people with PTSD continue to produce higher levels of stress hormones after the trauma is over, which may explain why emotional symptoms linger after the threat is gone.

Triggers are physical and emotional stimuli randomly associated with the traumatic experience. Sight, sound, smell, taste, and touch can act as triggers that cause a memory to light up the brain. Other examples of triggers include specific people, crowded places, songs, or emotions. When triggers are re-experienced, the brain sends signals to the body to prepare to defend itself against more trauma.

Because PTSD is repetitive and multilayered, triggers may cause false alarms. Some triggers are obvious to the person experiencing them and easy to understand. Others are buried in the subconscious, making it difficult to determine why the brain is overreacting. The triggered experience often causes depersonalization, which is when someone feels as if the memory is an out-of-body experience, or de-realization, when the experience feels unreal or distorted. When our warning signs are tripped, the ANS reengages our brain's hypothalamus and the process starts over again.

People with PTSD tend to isolate themselves and can suffer from depression. In response, they avoid situations, events, and people that remind them of their trauma. Other mental illnesses can occur after experiencing a traumatic episode, such as substance abuse or panic attacks. Sufferers can be seen as "unable to cope." Because of this, they may feel invalidated, ignored, and misunderstood.

PTSD is also known as the unseen or hidden wound. Those with PTSD say that they feel as if a pause button has been pushed on their life while the rest of the world moves on.

With social support, understanding, and empathy, people with PTSD can embrace their incredible personal strength, resiliency, and balance that they feel have been lost. Self-care, medication, mindfulness, and psychotherapy can help PTSD sufferers regain their self-esteem. Other exposure-based treatments, like cognitive behavioral therapy (CBT), Eye Movement Desensitization and Reprocessing (EMDR), group therapy, and psychotropic medication also help those experiencing PTSD.

PTSD can happen to anyone and is not a sign of weakness. With early detection, PTSD is significantly easier to treat. Know the warning signs of stress and PTSD before they feel out of control. To find out how to get help and support, click here.

In addition to being a prominent family and relationship psychotherapist and clinical director, the educator is also a published author who discusses military psychology, Behavioral Risk Threat Assessment, and wellness.

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The psychology of post-traumatic stress disorder - Joelle Maletis

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Many of us will experience some kind of trauma during our lifetime. Sometimes, we escape with no long-term effects. But for millions of people, those experiences linger, causing symptoms like flashbacks, nightmares, and negative thoughts that interfere with everyday life. Joelle Rabow Maletis details the science behind post-traumatic stress disorder, or PTSD.

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The myth of Hercules: 12 labors in 8-bits - Alex Gendler

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Hercules — son of Zeus and champion of humankind — stricken with a temporary curse of madness, has just committed the most unspeakable crime imaginable. Seeking to atone for the deaths of his family, Hercules must complete twelve impossible tasks that pit him against invincible monsters and unfathom…

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The binary system used in computers is a numeric system, like the decimal that we use in our day-to-day lives. The only difference between them is that the decimal uses ten symbols to represent numbers (0 to 9), while binary uses only two (0 and 1). This page has an interesting parallel between the two systems, including the representation of rational numbers. This lesson illustrates how the binary system is used, along with other numeric systems. In decimal systems, we know that any number can be represented-you just add digits as the represented number gets bigger. Hence, a system with "only" ten symbols is enough to represent virtually infinite possibilities. Binary works the exact same way: if you need to represent more information, you can add extra bits to your memory. However, using systems with less symbols is not easy: a number represented in binary requires around three times more digits to be written than its decimal representation.

Wouldn't it be better to use the widespread decimal system then? Actually, we use binary computers because binary devices are easier to implement than "decimal devices." Currently, a computer's central processing units (CPU) are made of electrical components called "transistors." Check out this lesson to see how transistors are made, how they operate, and how they have changed in the last century. Binary can also be implemented in multiple other ways. An optical fiber transmits data encoded in pulses of light, while hard disks store information using magnetic fields. You can check several examples of binary devices, even solutions that use more than one transistor to implement a single bit, here. The choice of which technology will be used depends specifically on each application and the most important parameters are cost, speed, size, and robustness.

Now that we know how to build devices that can represent numbers, we can expand their scope by mapping those numbers to a set of interest. A set of interest can be literally anything, such as letters in the alphabet or colors in a palette.

The effort to encode letters with industry standards began in the 1960s, when the American Standard Code for Information Interchange (ASCII) was developed. This encoding used 7 bits, which were mapped to the English letters and special characters. The values corresponding to each symbol are here. As computers became more popular worldwide, the need for tables containing more symbols emerged. Nowadays, the most used encoding is the UTF-8, which was created in 1993 and maps more than one million symbols to binary, including characters in all known alphabets and even emojis. You can navigate through the UTF-8 table here. In this encoding, each character can take one to four bytes to be represented, as shown in the first table here.

Colors are also mapped to binary sequences. Besides the RGB system, other systems were conceived to represent colors. The HSL system also uses three components to represent colors: hue, which varies from 0 to 360, with the color "red" being mapped to 0, "green" to 120 and "blue" to 240; saturation, which is the intensity of the colored component; and lightness, the "white level" of the color. The CMYK uses four components, corresponding to the levels of cyan, magenta, yellow, and black in the pixel. This system is called "subtractive," which means that, as a component gets larger, the pixel emits less light. It is very convenient for printers, where the ink acts as a "filter" for the white canvas of the paper. In this paragraph, the name of each color system has a link to interactive panels that allow you to see the colors corresponding to each possible encoding. If you want to see how those systems compare with each other, check this website.

It is possible to reduce the number of bits without losing information, optimizing data transmission or storage. Strategies that perform compression include the run-length encoding, the Lempel-Ziv algorithm, and the Huffman coding. The Lempel-Ziv algorithm replaces repeated patterns in the data with a token. Both the token and the pattern are added to the compressed file, so the decoder can accurately rebuild the original file. Although this post's discussion is not related to binary, it illustrates the Lempel-Ziv algorithm. The Huffman coding counts the number of occurrences of symbols in the file and creates a new binary encoding for each one of those symbols. Symbols that are more frequent receive a shorter binary sequence, reducing the size of the file. The ZIP files are created by using a combination of those algorithms.

Binary is a way to represent information like any other language. Engineers use international standards to attribute meaning to states of binary devices; they are able to represent letters, colors and even sounds. Just as a painting of pipe is not the pipe itself, the meaning of each bit is not embedded in itself, but in the program that reads it.

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How exactly does binary code work? - José Américo N L F Freitas

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Imagine trying to use words to describe every scene in a film, every note in a song, or every street in your town. Now imagine trying to do it using only the numbers 1 and 0.

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NASA vs. SpaceX - what’s the difference?

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What is the difference between NASA and SpaceX? How do the two compare? The Infographics Show explores the differences between the two.

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Edgar Allan Poe (1809-1849) was an innovative writer of fiction, poetry, literary theory, and criticism. You can explore all of his writings and read more about his life here.

Additional resources, particularly details about Poe's time in Richmond, VA, can be found here.

In 2017, PBS's American Masters series aired the film Edgar Allan Poe: Buried Alive, which provides a clear overview of his life and career.

One of the most carefully-researched and thorough biographies is Edgar A. Poe: Mournful and Never-ending Remembrance by Kenneth Silverman.

Edgar Allan Poe Revisited by the educator provides a concise, chronological overview of Poe's fiction, poetry, and criticism.

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Why should you read Edgar Allan Poe? - Scott Peeples

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The prisoner strapped under a descending pendulum blade. A raven who refuses to leave the narrator's chamber. A beating heart buried under the floorboards. Poe's macabre and innovative stories of gothic horror have left a timeless mark on literature. But just what is it that makes Edgar Allan Poe one of the greatest American authors?

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To learn more about 10-digit autobiographical numbers, check out Martin Gardner's Mathematical Circus.

Interestingly, we can expand on autobiographical numbers. Consider this: if there is a notion of an autobiography of a number, then it would be logical to expect there to be a notion of a biography of a number. What would be the logical candidate for a biography of a number? Let us say that given a number N, its biography is another number M such that the first digit of M is the number of zeroes in N, the second digit of M is the number of ones in N and so on.

For example, it is possible to have two numbers that are biographies of each other: 130 and 1101. Can you find two 10-digit numbers that are biographies of each other?

If you want to find out more about the biographies of numbers, check out the educator's "A Story of Storytelling Numbers."

You can also explore the educator's math blog here.

There are many interesting sequences that describe themselves. For example, the Golomb sequence, a(n), is lexicographically the earliest non-decreasing sequence of positive integers such that a(n) is the number of times that n occurs in the sequence. It has to start with 1: a(1) = 1. That means we have 1 one. Therefore, a(2) can't be 1. We pick the next smallest number available, so a(2) =2. Now we have to have 2 twos, so we need one more two. Thus a(3) = 2. The last equation says that the sequence has to have 2 threes. As we already used all ones and twos, we have a(4) = a(5) = 3. The first few terms of the sequence are:

1, 2, 2, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12.

This sequence is sequence A001462 in the Online Encyclopedia of Integer Sequences.

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Can you solve the Leonardo da Vinci riddle? - Tanya Khovanova

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You've found Leonardo da Vinci's secret vault, secured by a series of combination locks. Fortunately, your treasure map has three codes: 1210, 3211000, and... hmm. The last one appears to be missing. Can you figure out the last number and open the vault? Tanya Khovanova shows how.

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The story of Pandora is a powerful exploration of some of the most mysterious human traits, including agency, desire and, of course, curiosity. Visit this page for a beautiful meditation on the cultural history and representation of curiosity.

Check out Ian Leslie's book "Curious: The Desire to Know and Why Your Future Depends On It."

The first iteration of the Pandora myth has been traced back to the ancient Greek poet Hesiod, who believed that Pandora's experiences were a metaphor for the root of all evil. But her legacy is much more complicated-and Hesiod's Pandora has been revisited and scrutinized over time: click here for an exploration of the ways in which women have historically been treated in myths, as well as a discussion on how we move on from earlier versions. This article also provides a detailed overview of the myth's development over time - including what's been lost and what's been gained.

For painters and poets, the rich moral quandary of Pandora's box was a source of inspiration. The pre-Raphaelite artist Dante Gabriel Rossetti painted her with the fiery red hair of the movement's muses, and wrote of her releasing unknown forces into the world. Later, the French Surrealist artist René Magritte took an entirely abstract approach to the myth. He titled a 1951 painting of a figure surveying an empty street " La boîte de Pandore."

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The myth of Pandora's box - Iseult Gillespie

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Pandora was the first mortal woman, breathed into being by Hephaestus, god of fire. The gods gave her gifts of language, craftsmanship and emotion. From Zeus she received two gifts: the trait of curiosity and a heavy box screwed tightly shut -- never to be opened.

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How the Normans changed the history of Europe - Mark Robinson

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In the year 1066, 7,000 Norman infantry and knights sailed in warships across the English Channel. Their target: England, home to more than a million people. Around the same period of time, other groups of Normans were setting forth all across Europe. Who were these warriors, and how did they leave…

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The first naumachia, a mock sea battle, was held by Julius Caesar at the Campus Martius, which located on the Tiber River. By staging these nautical spectacles in their newly built Flavian Amphitheater (what we now call the Colosseum), the Flavian emperors hoped to send a message about their power over the Roman Empire and their legitimacy as a new dynasty. The main feat involved transporting the water; the ships and fighters themselves were not necessarily dressed in the most historically accurate costumes.

Naumachiae were part of a larger culture of water in Rome. This blog at the University of Massachusetts-Boston explores the connections among the staged sea battles with Roman aqueduct and sewer systems. By staging historical sea battles, Romans conveyed their dominance over culture, as well as over technology. Roman mock battles were staged purely as imperial entertainment.

The Roman legacy of staged sea battles has continued throughout the centuries. During the Renaissance, elite families such as the Medici would adopt the custom to underscore the significance of the ties created through their alliances; this included the 1589 wedding of Christine of Lorraine to Ferdinando de Medici. Even today, mock sea battles have been staged as cultural events in Queens.

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The Romans flooded the Colosseum for sea battles - Janelle Peters

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Starting in 80 CE, residents of Rome and visitors from across the Roman Empire would fill the stands of the Colosseum to see gladiators duel, animals fight and chariots race around the arena. And for the grand finale, water poured into the arena basin, submerging the stage for the greatest spectacle of all: staged naval battles.

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"It is a truth universally acknowledged, that a single man in possession of a good fortune, must be in want of a wife." The famous opening line to Jane Austen's Pride and Prejudice might suggest a stiff upper lip on first reading - but throughout her work Austen shows us that the truth is anything but stable, especially in matters of the heart. She expressed this outlook extensively and eloquently in her razor-sharp letters as well as her novels.

Over the course of her life, Austen published six novels - leaving one unfinished along with shorter works like Love and Friendshipand Lady Susan.Learn more about her lesser known writings here.
While her fiction centers on relationships, Austen rejected the sentimental style of the gothic romances that were popular at the time. Instead her understated tone, wry wit and close attention to language and behavior are key features of realism. Realists mined everyday life for deeper meaning, and Austen explored the minutiae of the society that surrounded her.

Born in 1755, she was familiar with the social circles reflected in her novels, and spent most of her life at her father's parish of Steventon. Visit an interactive historical timeline of her life here.

Today, the house Austen lived in for the last eight years of her life is a museum - visit the website here. You can also learn more about Austen's home life, and the objects Austen surrounded herself, in the unusual biography "Jane Austen at Home" and this feature on what we can learn from it. Find out more about her worldview and beliefs in this radio documentary, then listen to the mysterious story around her last completed novel Persuasion here.

Although she never married, the facts of Austen's love life are still being debated. She rejected the proposal of the aristocrat Harris Bigg-Wither, and some biographers have ruminated on letters that suggest the death of a romantic interest.

Austen's men are also intriguing figures who serve as foils to the development of female characters - such as when the philanderer John Willoughby leads Mariane Dashwood astray, only for her to realize her desire for substance as well as style. But Austen was also aware of the slights women suffered at the hands of men, such as when the obsequious Henry dismisses Catherine in Northanger Abbey: "no one can think more highly of the understanding of women than I do. In my opinion, nature has given them so much that they never find it necessary to use more than half."

Today, Austen remains beloved for her lovable heroines, stinging takedowns and romantic revelations. She has fans in a ll corners of the world, for many different reasons. Read more of her work to find out what resonates with you.

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The wicked wit of Jane Austen - Iseult Gillespie

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Whether she's describing bickering families, quiet declarations of love, or juicy gossip, Jane Austen's writing often feels as though it was written just for you. Her dry wit and cheeky playfulness informs her heroines, whose conversational tone welcomes readers with a conspiratorial wink. Iseult Gillespie explores the sly societal satire and unique tongue-in-cheek humor of Jane Austen.

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The dangerous race for the South Pole - Elizabeth Leane

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By the early 1900’s, nearly every region of the globe had been visited and mapped, with only two key locations left: the North and South Poles. After two Americans staked claim to reaching the North Pole, a Norwegian explorer and a British naval officer each set out for the last unmapped region in what newspapers called a “Race to the Pole.” Elizabeth Leane sets the scene for their journeys south.

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What's a smartphone made of? - Kim Preshoff

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As of 2018, there are around 2.5 billion smartphone users in the world. If we broke open all the newest phones and split them into their component parts, that would produce around 85,000 kg of gold, 875,000 of silver, and 40,000,000 of copper. How did this precious cache get into our phones--and can we reclaim it?

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Here is a basic guide to how ocean currents work around the world.

Smithsonian has a great video and other resources on ocean currents here.

Here is a resource from Yale Environment 360 on how climate change is affecting ocean currents.

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How do ocean currents work? - Jennifer Verduin

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In 1992, a cargo ship carrying bath toys got caught in a storm. Shipping containers washed overboard, and the waves swept 28,000 rubber ducks and other toys into the North Pacific. But they didn't stick together -- the ducks have since washed up all over the world. How did this happen?

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Many crystals have signature shapes- like the cascade of pointed quartz or a pile of galena cubes. Every crystal's atoms have a defining feature: their organized, repeating pattern. The pattern isn't restricted to minerals- sand, ice, metals and DNA also have crystalline structures. So what causes them to grow into these shapes again and again? Graham Baird dives into the unique properties of crystals.

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Music Carlos Palomares

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Associate Editorial Producer Elizabeth Cox

Script Editor Emma Bryce , Alex Gendler

Fact-Checker Brian Gutierrez

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Many crystals have signature shapes- like the cascade of pointed quartz or a pile of galena cubes. Every crystal's atoms have a defining feature: their organized, repeating pattern. The pattern isn't restricted to minerals- sand, ice, metals and DNA also have crystalline structures. So what causes them to grow into these shapes again and again?

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In ancient times, wildcats were fierce carnivorous hunters. And unlike dogs, who have undergone centuries of selective breeding, modern cats are genetically very similar to ancient cats. How did these solitary, fierce predators become our sofa sidekicks? Eva-Maria Geigl traces the domestication of the modern house cat.

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Educator Eva-Maria Geigl

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Composer Draško Ivezić

Content Producer Gerta Xhelo

Editorial Producer Alex Rosenthal

Associate Producer Bethany Cutmore-Scott

Associate Editorial Producer Dan Kwartler

Fact-Checker Francisco Diez

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The history of the world according to cats - Eva-Maria Geigl

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In ancient times, wildcats were fierce carnivorous hunters. And unlike dogs, who have undergone centuries of selective breeding, modern cats are genetically very similar to ancient cats. How did these solitary, fierce predators become our sofa sidekicks? Eva-Maria Geigl traces the domestication of the modern house cat.

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During the middle ages, the Icelanders wrote extensively in Icelandic rather than Latin which was the norm for that period. The Icelandic sagas, mostly written in the 13 th century, give us some of the historical and cultural information about the period between 800 to 1100 for the Nordic area. This was a time of flux. The Nordic area went from a clan-based society to a kingship-base one and were developing into the countries we know today: Norway, Denmark Finland, Iceland, and Sweden. There was also a change in religion, from the traditional polytheist religion; which included gods like Odin, Frey, Thor, Frigg, Freya and Sif; to Christianity.

Much of our information on Norse mythology comes from the Icelanders. After a trip to Norway from 1218 to 1220, the Icelandic law speaker and poet, Snorri Sturluson, returned to Iceland and wrote the , which was a prose version of the Old Norse myths. It is believed that he based much of his prose version on the earlier Poetic Edda, a poetic version of the Old Norse myths from about 40 years previously, which scholars earlier had attributed to the Icelander Sæmundr hinn fróði (the wise) but later was realized not to be true and currently is considered anonymous.

One of the problems with Snorri's Edda, and even the Poetic Edda, is that it was written two hundred years after the conversion to Christianity and, therefore, long after the polytheist religion was no longer being practiced on Iceland, or even in Scandinavia. During the 13 th century in Christian Europe, a dominant method of critical thought was called Scholasticism. Monastic schools were forming into the first universities, and a component of education was this developing philosophical system for Christian theology that, among other things, attempted to reconcile the bible with classical philosophy. Some Icelanders were familiar with this philosophy, a few even having studied at these early universities. Snorri was not a clergyman, rather an aristocratic layman, nor did he study at a European university. Nevertheless, his text demonstrates some of these ecclesiastical teachings. In his introduction, Snorri attempts to reconcile the Bible and Classical literature with traditional Norse belief by claiming that the old Norse gods had originally come from Troy and had come to Sweden and taught the polytheist belief to a Swedish king, thereby deluding this king into believing that they were gods. As a result, we need to be very careful using Snorri's text for our understanding of the pre-Christian religion.

Snorri is very good, however, in giving us comprehensible stories, like this story of how Thor got his hammer. Though his book may tell us more about the 13 th century than the 10 th, some of the stories are helpful in giving us insight to both 13 th and 10 th century society. We discover the importance of the smith to medieval Norse society. And we might extrapolate, based on the gifts given to the gods, these items' importance. Sif's hair, golden as summer wheat, is reflective of agriculture, whereas the golden boar is suggestive of animal husbandry, both important food sources for the Norse. Spears were important in warfare and ships were an integral component of Norse society during this period. Gold and arm rings were used in gift giving which created important relationships between people, and hammers would have been of cultural importance for a number of reasons, for ship building, smithing and carpentry.

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How Thor got his hammer - Scott A. Mellor

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Loki the mischief-maker, writhes in Thor's iron grip. The previous night, he'd snuck up on Thor's wife and shorn off her beautiful hair. To fix what he'd done, Loki rushes to the dwarves and tricks them into making gifts for the gods.

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Why should you read “Fahrenheit 451”? - Iseult Gillespie

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Ray Bradbury’s novel imagines a world where books are banned- and possessing, let alone reading them, is forbidden.The protagonist, Montag, is a fireman responsible for destroying what remains. The story raises the question: how can you preserve your mind in a society where free will, self-expressio…

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In 2008, UNESCO recognized the importance of Día de los Muertos by adding the holiday to its list of Intangible Cultural Heritage of Humanity. Day of the Dead festivities unfold over two days in an explosion of color and life-affirming joy. The theme is death, but the point is to demonstrate love and respect for deceased family members. It originated several thousand years ago with the Aztec, Toltec, and other Nahua people, who considered mourning the dead disrespectful.

The centerpiece of the celebration is an altar, or ofrenda, built in private homes and cemeteries. These aren't altars for worshipping; rather, they're meant to welcome spirits back to the realm of the living.

Calavera was used to describe short, humorous poems, which were often sarcastic tombstone epitaphs published in newspapers that poked fun at the living and are a popular part of the celebrations. Mexican political cartoonist and lithographer José Guadalupe Posada created an etching to accompany a literary calavera. In 1947, artist Diego Rivera featured Posada's stylized skeleton in a mural and named her Catrina, slang for "the rich." Today, the calavera Catrina, or elegant skull, is the Day of the Dead's most ubiquitous symbol.

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The Egyptian Book of the Dead: A guidebook for the underworld
Ancient Egyptians believed that in order to become immortal after death, a spirit must first pass through the underworld - a realm of vast caverns, lakes of fire, and magical gates. Needless to say, one needed to come prepared. But how? Tejal Gala describes an Egyptian "Book of the Dead" -- a customized magic scroll written by the living to promote a smooth passage to the afterlife when they died.

How to make a mummy
As anyone who's seen a mummy knows, ancient Egyptian priests went to a lot of trouble to evade decomposition. But how successful were they? Len Bloch details the mummification process and examines its results thousands of years later.

At what moment are you dead?
For as far back as we can trace our existence, humans have been fascinated with death and resurrection. But is resurrection really possible? And what is the actual difference between a living creature and a dead body anyway? Randall Hayes delves into the scientific theories that seek to answer these age-old questions.

The fascinating history of cemeteries
Spindly trees, rusted gates, crumbling stone, a solitary mourner: these things come to mind when we think of cemeteries. But not long ago, many burial grounds were lively places, with gardens and crowds of people -- and for much of human history, we didn't bury our dead at all. How did cemeteries become what they are today? Keith Eggener delves into our ever-evolving rituals for honoring the dead.

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What is Día de los Muertos, the Day of the Dead?

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Día de los Muertos, or Day of the Dead, is a celebration of life and death. While the holiday originated in Mexico, it is celebrated all over Latin America. The British Museum shows how every year the dead are remembered and summoned by the observances of the living, who cook, make music and decorate their graves.

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Gravity is certainly the most familiar force out of the four fundamental forces we know. We can see and feel its effects on us and on our surroundings every day. Gravity keeps us grounded - literary. Nevertheless there are still many open questions regarding gravitation and its nature - in example that it is incredibly weak compared to the strength of the other three fundamental forces.

Physicist and broadcaster Jim Al-Khalili addresses some of the many fascinating aspects of gravity in a highly regarded documentary- you can have a look at it .
The variations in acceleration due to gravitation on Earth can have even unexpected effects - like even influencing timekeeping! In a magazine article, astrophysicist and author Ethan Siegel tells the story of why timekeeping first failed in the Americas and the physics behind it - an interesting and also funny episode in history.

The recent first detections of gravitational waves opened up a new field in observational astronomy. It also showed that there are still areas in this field of science open for discoveries to be made. The observations resulted in the 2017 Nobel Prize in Physics awarded to three of the major contributors to enable these discoveries. Learning from Gravitational Waves tells a little bit about the LIGO (Laser Interferometer Gravitational-Wave Observatory) facility, its history and why this research is important.

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How far would you have to go to escape gravity? - Rene Laufer

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Every star, black hole, human being, smartphone and atom are all constantly pulling on each other due to one force: gravity. So why don't we feel pulled in billions of different directions? And is there anywhere in the universe where we'd be free of its pull? Rene Laufer details the inescapability of gravity.

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Echolocation allows creatures to move around in pitch darkness, so they can navigate, hunt, identify friends and enemies, and avoid obstacles. Bats are not the only species that uses echolocation. For dolphins and toothed whales, this technique enables them to see in muddy waters or dark ocean depths, and may even have evolved so that they can chase squid and other deep-diving species. Another intriguing possibility is humans - many blind people can find their way around simply by listening to echoes bouncing off surrounding objects. Scientists have been experimenting to see if humans can use technology to emulate nature's use of ultrasonic sound to create assistive devices for the blind.

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What flies through the night, silently guarding and protecting our world from evil? Batman? Try...a bat. Like Batman, bats are widely misunderstood and vilified. Amy Wray disproves the myth that bats are dangerous villains and explains why they, instead, deserve a hero's welcome -- and our protection.

How do animals see in the dark?
To human eyes, the world at night is a formless canvas of grey. Many nocturnal animals, on the other hand, experience a rich and varied world, bursting with details, shapes, and colors. What is it, then, that separates moths from men? Anna Stöckl uncovers the science behind night vision.

Inside the minds of animals
Do animals think? It's a question that has intrigued scientists for thousands of years, inspiring them to come up with different methods and criteria to measure the intelligence of animals. Bryan B Rasmussen navigates through this controversial question, showing how determining intelligence often says more about how humans think than about anything else.

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Echolocation allows creatures to move around in pitch darkness, so they can navigate, hunt, identify friends and enemies, and avoid obstacles. Bats are not the only species that uses echolocation. For dolphins and toothed whales, this technique enables them to see in muddy waters or dark ocean depths, and may even have evolved so that they can chase squid and other deep-diving species.

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Are you a good golfer or a poor one? What just might help you improve? Your swing, your stance, or could it be the golf ball? How much could that little, dimpled ball be affecting your play?

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The golf ball that made golfers too good

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Are you a good golfer or a poor one? What just might help you improve? Your swing, your stance, or could it be the golf ball? How much could that little, dimpled ball be affecting your play?

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Why is this painting so shocking? - Iseult Gillespie

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In 1937, in one of the worst civilian casualties of the Spanish Civil War, Fascist forces bombed the village of Guernica in Northern Spain. For Pablo Picasso, the tragedy sparked a frenzied period of work in which he produced a massive anti-war mural, titled “Guernica.” How can we make sense of this…

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What makes TB the world's most infectious killer? - Melvin Sanicas

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In 2008, two 9,000-year old skeletons were found with their bones infected by an all too familiar bacterium. The ancient Greeks knew its effects as phthisis; the Incans called it chaky oncay; and today we call it tuberculosis, or TB. TB is still one of the world's most infectious killers, causing more deaths than malaria or even HIV.

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Handing over a car's steering wheel to a disembodied decision-maker cuts to the heart of our anxiety about an over-reliance on advanced machines. But our mastery of light-based technology and computers has already led to a reliable internet and cloud computing society. Check out this TED-Ed video on fiber optics and integrated photonics-light-manipulating devices that are surely and steadily transforming mobile communications, sensors, and 3D laser-based LiDAR imaging.

If you're curious, learn of the variety of LiDAR uses-from airborne mapping of a forgotten Mayan city in the Guatemalan jungle to tracking water vapor and measuring windflow, or snow depth to predict avalanches. Then, take a short primer on how LiDAR works; to learn more, consult a National Academies Press review and a LiDAR calculator on imaging resolution.

Next, go one step closer to a LiDAR chip with a version that fits in the palm of your hand: the FaceID feature in the iPhone X smartphone, based on a Time-of-Flight (ToF) sensor. What new ethics questions in biometrics does FaceID raise? Dive into augmented imaging with a technical article on Microsoft's Kinect 3D sensor, which detects user gestures to create a holographic mixed reality via a HoloLens display. If you feel ambitious, challenge yourself with articles on LiDAR calibration errors and complex imaging techniques.

This scientific article reviews ToF for measuring distance-aka ranging-by laser pulses. An academic blog post and tutorial by Adafruit show how to run a ToF LiDAR sensor; in these low speed sensors, an infrared laser is switched on/off to create pulses. As this direct modulation rate increases (for higher depth resolution or sampling rate), laser instabilities such as timing jitter and frequency chirp limit ToF precision. For a laser pulse of less than half a nanosecond, an external Mach-Zehnder modulator creates stable signals; with integrated photonics, a low power/high speed version can enhance ToF LiDAR. Review the century-old concept of a M-Z interferometer: measuring the phase difference between two waves as a change in light intensity.

When a light pulse reflects from an object's surface, the Avalanche PhotoDiode (learn more here) enables faster detection to overcome the conventional relation between pulse duration and depth resolution. Articles by Toyota researchers and academics describe how APD designs achieve single photon counting in precise measurements, and rely on a pixel camera layout to rapidly map 3D objects. New innovations in LiDAR include filters to improve signal-to-noise ratio, and slow modulation or random modulation of laser light-as opposed to pulsing-to increase ranging accuracy and lower laser power. Finally, learn more on laser beam steering and how an integrated photonic chip does this with a bank of phase modulators.

The verdict is still out on how comprehensive LiDAR will be as a 3D imaging tool in self-driving cars. This accessible article by Jeff Hecht thoroughly reviews automobile LiDAR and its competitors. Check out a WIRED video on autonomous cars with LiDAR in action. While the car-maker Luminar strives to design low power LiDAR and Waymo focuses on low cost production, the transition to LiDAR chips has begun with cheaper solid state LiDAR by Velodyne and Quanergy Systems. Tesla has taken a firm position against LiDAR for its cars in favor of microwave radar: this review and blog contrast the two approaches. Radar can be packaged compactly-to a point, and mmWave imaging can image comparable detail as LiDAR, but it lacks depth resolution.

In contrast to LiDAR's ToF rendering of "3D point cloud" images, human eyes rely on stereoscopic vision to perceive depth, and this online explainer clarifies the distinction between depth of field and depth of focus. Explore how we infer depth in a Scientific American article and an online primer, and how people with monocular vision manage this feat. Take a crack at a classic paper on stereoscopic depth perception and learn recent leading insights from academia.

To learn more on integrated photonics and how the technology is transforming low power cloud computing, hyperfast wireless, smart sensing, and augmented imaging, visit the AIM Photonics Institute and its education program at MIT, AIM Photonics Academy. Then, step back to learn about similar advanced Manufacturing institutes like AIM that are transforming robotics, smart fabrics, flexible electronics, 3D printing, bio-fabrication, and other high-tech fields.

Sajan Saini is a former materials scientist and science writer. He directs the educational curriculum for AIM Photonics Academy at MIT. He has written for Coda Quarterly, MIT Ask an Engineer, Harper's Magazine, and TED-Ed. Learn about Sajan here.

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How do self-driving cars "see"? - Sajan Saini

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It's late, pitch dark and a self-driving car winds down a narrow country road. Suddenly, three hazards appear at the same time. With no human at the wheel, the car uses smart eyes, sensors that'll resolve these details all in a split-second. How is this possible?

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336,176 Views

TEDEd Animation

Let's Begin...

This animation is part of our series, "There's a Poem for That," which features animated interpretations of poems both old and new that give language to some of life's biggest feelings. Check out the full series here: http://bit.ly/TEDEdTheresAPoemForThat

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"All the World's a Stage" by William Shakespeare

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336,176 Views TEDEd Animation Let's Begin... This animation is part of our series, "There's a Poem for That," which features animated interpretations of poems both old and new that give language to some of life's biggest feelings. Check out the full series here: http://bit.ly/TEDEdTheresAPoemForThat Create and share a new lesson based on this one.

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The hidden network that makes the internet possible - Sajan Saini

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In 2012, a team of researchers set a world record, transmitting 1 petabit of data— that’s 10,000 hours of high-def video— over a fifty-kilometer cable, in a second. This wasn’t just any cable. It was a souped-up version of fiber optics, the hidden network that links our planet and makes the internet…

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This animation is part of our series, "There's a Poem for That," which features animated interpretations of poems both old and new that give language to some of life's biggest feelings. Check out the full series here: http://bit.ly/TEDEdTheresAPoemForThat

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Cloudy climate change: How clouds affect Earth's temperature
As the Earth's surface temperature gradually rises, it has become vital for us to predict the rate of this increase with as much precision as possible. In order to do that, scientists need to understand more about aerosols and clouds. Jasper Kirkby details an experiment at CERN that aims to do just that.

How heavy is air?
Too often we think of air as empty space - but compared to a vacuum, air is actually pretty heavy. So, just how heavy is it? And if it's so heavy, why doesn't it crush us? Dan Quinn describes the fundamentals of air pressure and explains how it affects our bodies, the weather and the universe at large.

Is our climate headed for a mathematical tipping point?
Scientists have warned that as CO2 levels in the atmosphere rise an increase in Earth's temperature by even two degrees could lead to catastrophic effects across the world. But how can such a tiny, measurable change in one factor lead to huge, unpredictable changes elsewhere? Victor J. Donnay uses billiards to illustrate tipping points, chaotic motion and their implications on climate change.

The disarming case to act right now on climate change
In this passionate call to action, 16-year-old climate activist Greta Thunberg explains why, in August 2018, she walked out of school and organized a strike to raise awareness of global warming, protesting outside the Swedish parliament and grabbing the world's attention.

Why humans are so bad at thinking about climate change
The biggest problem for the climate change fight isn't technology - it's human psychology. Vox takes a look at efforts energy-saving companies are taking to take advantage of human psychology.

Climate change: Earth's giant game of Tetris
There's a game of Tetris happening on a global scale: The playing space is planet Earth, and all those pesky, stacking blocks represent carbon dioxide -- a greenhouse gas that is piling up ever more rapidly as we burn the fossil fuels that run our cars, factories and power plants. Joss Fong outlines how this overload of CO2 leads to climate change and reminds us that, unlike Tetris, we won't get an opportunity to start over and try again.

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What's the difference between weather and climate?

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We have weather and we have climate... but are they the same thing? The short answer is no, but they are both incredibly important to how the geosphere is shaped. Crash Course dives into the differences between weather and climate.

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The myth of Jason and the Argonauts - Iseult Gillespie

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Hercules, the strongest man alive with a mighty heart to match. Orpheus, charmer of nature and master of music. Castor and Pollux, the twin tricksters. The Boreads, sons of the North Wind who could hurtle through the air. Brought together by a young man's call for help, these heroes joined forces and named themselves the Argonauts.

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Born in Coyoacán in 1907, Kahlo is known for her resplendent imagery and unapologetic individualism. Animals and plants, along with her body, pain and spirituality, became signature themes of her unique visual language. She painted many eerie portraits, still lives and spiritual scenes - but it is her mesmerizing self-portraits which first caught people's attention, and continued to captivate after her death.

Such work is groundbreaking because it turned self-portraiture inward - especially at a time when women often inhabited art only as men saw them. Kahlo insisted her personal experience mattered, and boldly documented the circumstances of her body, beliefs and every day life. These are often conveyed through symbols, which can be as sensuous as they are gruesome: from giant floating flowers and undulating landscapes, to transplanted body parts, skulls and billowing clouds of demons. Click here for an online archive of her art, then listen to this radio documentary about her life and work. You can also access Kahlo's life in her own words, through her published diary and journal sketches.

A closer look at her reality reveals the stuff of dreams brought to life. Kahlo split her time between her deep blue childhood home, La Casa Azul (which you can now visit as a museum dedicated to her life and work) and her modern studio in Mexico City, which was connected by a bridge to her husband's quarters, the painter Diego Rivera. Today, their connected studios is also a museum, and known as an architectural wonder. At home, Kahlo was often accompanied by her numerous wild pets including deers, birds and monkeys - all of which played a role in her art.

Along with her artistic commitments, she held uncompromising political beliefs. She had a deep affinity with Mexicanidad, a movement which celebrated indigenous culture after the Revolution. Click here to view a short documentary about the relationship of political revolution to the development of Mexican art at this time.

Kahlo also expressed her nationalism in her daily life. She frequently wore traditional Tehuana dress, and dedicated herself to the study of Mexican traditions and spirituality. .She was also was a devotee of Karl Marx, who appears in several of her paintings, and a fierce member of the Mexican Communist party.

It was at a Communist gathering that she met Rivera. Their tempestuous relationship was marked by infidelity on both sides - Kahlo was openly bisexual - and the two divorced in 1939...only to remarry a year later. Rivera features prominently in Kahlo's work, appearing in person in more realistic portraits as well in the wild forms like a giant baby, or as Kahlo's third eye. Read extracts of her beautiful tribute to Rivera here.

Over the past few years, fans have flocked to her colorful biography, style and legacy.. The trend for Kahlo merchandise and fascination with her life has been termed "Frida-mania", and has sometimes been criticized for simplifying her life and appropriating her unique and complex vision. This article argues for the value of looking at her identity and work in all its complexity - from her experience as a woman with disabilities, to her relationship with her country's history and heritage and her radical political views.

In Kahlo's work, there are no simple answers or singular truths about a woman who became an icon Rather she explores a blazing desire to survive on her own terms alongside some of the rawest visual depictions of despair. By mining her reality for multiple meanings, she provided us with an extraordinary body of work - and an insight into the contents of her soul.

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Frida Kahlo: The woman behind the legend - Iseult Gillespie

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In 1925, Frida Kahlo was on her way home from school in Mexico City when the bus she was riding collided with a streetcar. She suffered near-fatal injuries and her disability became a major theme in her paintings. Over the course of her life, she would establish herself as the creator and muse behind extraordinary pieces of art.

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The life and achievements of Stephen Hawking, the British cosmologist who theorized the black hole evaporation, are outstanding from many points of view. A nice portrait of his exceptional personal life and of his scientific endeavors is provided by the recent movie " The Theory of Everything " (2014) by James Marsh. Of course, for a larger-than-life character like Hawking, a "Dig Deeper" section is far from enough to describe his entire life. We will then focus on a very limited aspect of his scientific life: his passion for scientific wagers, or bets. Two of them are very famous and remarkable, with one being directly related to our story of black hole evaporation.

In 1975 Stephen Hawking bet with his colleague (and recent Nobel Laureate for Physics) Kip Thorne that a very peculiar source, named Cygnus X-1, would turn out not to be a black hole. Cygnus X-1 was discovered in 1964 during the first observations of the X-ray sky. It is an extremely intense emitter of X-rays located in our own Galaxy. The system turned out to be composed of two elements: a very hot, super-giant star and a massive compact object, with a mass of about 14.8 times the mass of the Sun. Because this mass is significantly larger than the so-called Tolman-Oppenheimer-Volkoff limit, which provides an approximation for the maximum mass to avoid an infinite gravitational collapse, Cygnus X-1 was identified as a black hole. In 1990, 26 years after the discovery, Hawking conceded the bet, acknowledging that improved observations led to the conclusion that Cygnus X-1 was indeed the first black hole ever discovered. Diligently, Hawking paid Thorne a subscription to the magazine Penthouse (!).

In 1997, not satisfied with the previous wager, Stephen Hawking and Kip Thorne made a bet with John Preskill on a very peculiar consequence of the evaporation of black holes, nowadays known as the information paradox. Without going into details of this paradox, which will be the focus of another TED-Ed lesson, let's summarize it as follows. Physics requires that a quantity, which we will call "information", is always conserved. The evaporation of a black hole, instead, seems to suggest that information is lost during the process. While Hawking and Thorne bet that information is indeed lost in a black hole, Preskill bet that it must not, under any circumstances. The prize for the winner was, quite obviously, an encyclopedia of choice, definitely a book with plenty of information. Hawking ended up convincing himself that information is not lost and conceding the bet in 2004, while Thorne has not conceded yet. The original paper presenting Hawking's argument to show that information is not lost can be found here. The encyclopedia of choice for the winner was: "Total Baseball, The Ultimate Baseball Encyclopedia" (!). To this date, the bet is still open and the information paradox unsolved.

If you are interested in calculating properties of any black hole of your choice, including its evaporation time, try out the Black Hole Calculator of the author of this TED-Ed lesson.

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Can a black hole be destroyed? - Fabio Pacucci

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Black holes are among the most destructive objects in the universe. Anything that gets too close to a black hole, be it an asteroid, planet, or star, risks being torn apart by its extreme gravitational field. By some accounts, the universe may eventually consist entirely of black holes.

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Many factors affect how air or water flows. Viscosity is the ultimate dissipator of energy and thus always acts to decrease turbulence. However, there are many other factors that modify turbulence and even keep it from forming in the first place. In planetary flows (atmosphere and oceans) two of these factors are rotation by the Earth and what we call stratification.

The whole Earth rotates, and that affects every fluid that rotates with it to a certain degree. Although the effect is too small to make a difference in small flows (like your toilet or a cup of coffee), it has a large effect on flows at larger scales, such as weather systems. This effect is generally called the Coriolis effect, and you can see how it affects major weather systems in this video. Effects of rotation can be estimated using the Rossby number.

Stratification, on the hand, has to do with how the density (or weight) of the fluid is distributed. If there is heavier fluid sitting on top of lighter fluid, then we say that the stratification is unstable and turbulence tends to form. If, on the other hand, lighter fluid is sitting on top of heavy one, it will be difficult for turbulence to form even through the action of an exterior force. In geophysical flows, the Froude and Richardson numbers are two relevant parameters used to infer stratification effects. Stratification effects can lead to an interesting phenomenon called Kelvin-Helmholtz instability.

If you are interested in a more rigorous (and therefore somewhat mathy) discussion on Turbulence, a good place to start is this Special thanks to Ken Zhao of UCLA.

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Turbulence: one of the great unsolved mysteries of physics - Tomás Chor

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You're on an airplane when you feel a sudden jolt. Outside your window nothing seems to be happening, yet the plane continues to rattle you and your fellow passengers as it passes through turbulent air in the atmosphere. What exactly is turbulence, and why does it happen?

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Why should you read Dante’s “Divine Comedy”? - Sheila Marie Orfano

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“Abandon all hope, ye who enter here…” Inscribed above the Gate of Hell, this prophecy sets into motion an epic journey for salvation. Written over 10 years, Dante Alighieri’s three-part narrative poem “Divine Comedy” is both an allegorical imagining of the soul’s journey towards God and a scathing political commentary. Sheila Maria Orfano shares its timeless themes of love, sin and redemption.

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Dig Deeper into understanding the WWII incarceration of Japanese Americans through oral history and other primary sources paired here with activities designed for the middle school or high school classroom. These learning activities will help students engage with the history and think critically about how the past can inform understandings of the present.

Pre-War & Pearl HarborDespite facing prejudice and discriminatory laws, thousands of Japanese immigrants came to the United States starting in the mid-1800s. By the time Aki was born in 1925, there were thousands of Japanese American workers, farmers, business owners, and others building lives in the US. Watch: A Community Grows, Despite Racism

When Japan bombed Pearl Harbor on December 7, 1941 the government retaliated against Japanese Americans even though a decade of surveillance proved there was no reason to suspect they posed any harm to the US. Even so, Japanese community leaders were rounded up by the army, FBI, and local police without any charges (and often with no warrants). These individuals were usually told they would be gone a few hours, but many of them were detained for the entire war. Watch: Aki Kurose talks about facing discrimination the day after Pearl Harbor

Classroom activity I: Phrase/Word Thinking Routine
- Activity instructions
- Aki Kurose oral history transcript I
- Classroom demo

Classroom activity II: Found Poem (this activity builds on the Phrase/Word activity)
- Activity instructions
- Classroom demo

Media Representations and Minidoka Concentration Camp After Pearl Harbor, media portrayals of Japanese Americans helped to stoke anti-Japanese sentiment. This classroom activity will help your students look closely at primary source images and make interpretations based on evidence.

Classroom activity: Zoom In
- Activity Instructions
- Powerpoint slideshow to facilitate the activity
- Classroom demo

In February 1942, President Franklin D. Roosevelt signed Executive Order 9066, which authorized the forcible removal of Japanese American men, women, and children from "exclusion zones" on the West Coast. Most were first held in temporary detention facilities and then relocated to more permanent concentration camps that had been quickly constructed in desolate areas of California, Idaho, Utah, Arizona, Colorado, Wyoming, and Arkansas. More than 120,000 Japanese Americans were imprisoned, two-thirds of whom were US citizens. Watch: American Concentration Camps

Aki and her family were incarcerated first at the Puyallup Fair Grounds outside of Seattle and, later, in the Minidoka concentration camp in Idaho. As a teenage girl, the lack of privacy and the disruption of family time posed some of the biggest challenges.

Watch: Aki remembers life at Minidoka "The thing I felt most was the lack of privacy."

Japanese American responses to WWII incarceration varied greatly. Some chose to prove their loyalty to the US by signing up to join the army. Others resisted incarceration and pursued legal challenges. Watch: Japanese American Responses to Incarceration

Post-War America and Finding Empowerment Through Peace After graduating from high school at Minidoka, Aki was granted leave to attend Friends University, a Quaker College in Wichita, Kansas. She later married and resettled in Chicago, along with thousands of other Japanese Americans as they were released from the camps. It would be decades before activists were able to win an official apology and redress from the US government. Watch Righting a Wrong

By the time she made her way back to Seattle and enrolled her six children in school, the civil rights movement was in full swing. Aki and her family faced ongoing discrimination and she saw the way other communities had been impacted by racism too, but she found peace through her commitment to activism. Watch Aki talk about finding empowerment through peace

Classroom Activity: Group quilt and examining what inspires our own commitment to action
- Activity description
- Aki Kurose oral history transcript II
For use in a virtual classroom environment: Classroom Activity 1: Step In, Step Out, Step Back
Purpose: To give students practice in reflecting on their own perspective and thinking about someone else's perspective on an experience or event.

Step In, Step Out, Step Back is a thinking routine adapted from Harvard Project Zero's Thinking Routine Toolbox

Thinking routines are simple strategies that teachers can use to cultivate thinking and deepen learning for students.

Step In, Step Out, Step Back is a routine that helps students gain experience in the challenging cognitive and emotional task of taking someone else's perspective. "Standing in someone else's shoes" helps students avoid making stereotypes and projecting their own values and beliefs onto others and gain appreciation for the value of multiple perspectives.

See Activity 1 instructions here.
Classroom Activity 2: See, Think, Wonder
Purpose: To encourage students to look carefully at visual media, and to make thoughtful observations and interpretations.

See, Think, Wonder is a thinking routine adapted from Harvard Project Zero's Thinking Routine Toolbox.

Thinking routines are simple strategies that teachers can use to cultivate thinking and deepen learning for students.

See, Think, Wonder is a thinking routine that encourages students to make careful observations and thoughtful interpretations. It helps stimulate curiosity and promote critical thinking.

A World War II era photograph by well-known photographer, Dorothea Lange, is used for this lesson. The photograph shows a boarded up store in Oakland, CA that is for sale. The store owner was a Japanese American University of California graduate. The owner placed the "I Am An American" sign on the storefront on December 8, 1941, the day after Pearl Harbor. Soon after, all Japanese Americans living on the West Coast were forcibly removed to temporary detention centers, then to concentration camps. They were forced to rent, sell or abandon their homes, businesses, and other property, often with only a few days' notice.

See Activity 2 Instructions here.
Classroom Activity 3: The Power of Words
Purpose: To help students think critically about the language used to name or describe experiences or events.

This activity examines how language shapes our perception of events and how it can be used to manipulate our thoughts and feelings. It is based on Densho's article on Terminology and explores the euphemisms used to describe the incarceration of Japanese Americans during World War II.

See Activity 3 instructions here.

Additional Resources
-Short films on Japanese American history before, during, and after WWII.
- Teaching Japanese American History withPrimary Sources (free online course for educators)
- Densho Encyclopedia
- Densho Guide to Media on the Japanese American Removal and Incarceration

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Ugly History: Japanese American incarceration camps - Densho

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On December 7, 1941, 16 year-old Aki Kurose shared in the horror of millions of Americans when Japanese planes attacked Pearl Harbor. Unbeknownst to her, this shared experience would soon leave her family and over 120,000 Japanese Americans alienated from their country, both socially and physically.

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What responsibility do we have to the dead? Should we forget the past if our future is at stake? And to what extent are we in control of how the world perceives us? Such big existential questions loom over Hamlet? To add to this turmoil, the question of madness hangs Shakespeare's most psychological play. Is Hamlet's mental state part of a performance to confuse his enemies, or are we watching a character on the brink of sanity? All these questions weigh heavily on Hamlet's interactions with every single character, whether friend and foe. The play can be found, in its entirety and annotated, through Folger Digital Texts. You can also listen to deep dives into the world of the play with The Hamlet Podcast.

Shakespeare's use of bad timing and delayed action throughout the play suggests that the path to revenge is never straightforward. Although we are generally encouraged to sympathize with Hamlet, Shakespeare offers us two other characters who have different approaches to revenge: the invading prince of Norway Fortinbras, whose father was killed in battle with Denmark; and the determined Laertes, who arrives to investigate the mysterious circumstances surrounding his own father's death. These focused figures heighten our fear that Hamlet's schemes are spiraling out of control.

The story and characters of Hamlet have created a rich mine for screen adaptation and interpretation - from Laurence Olivier's epic traditional take - see his "to be or not to be here" - to Disney's The Lion King and the acclaimed adaptation by Japanese director Akira Kurosawa, translated into English as The Bad Sleep Well. References to Hamlet's language and plot are also threaded through pop culture, as this article explains.

Hamlet, of course, has a rich stage history - an overview of which can be found in this Royal Shakespeare Company piece. You can watch this documentary to learn about the joys and challenges of staging and interpreting Hamlet; then listen to this conversation amongst some of the actors who have recently played the moody prince. There is a long history of women playing Hamlet, too.

But title character is not the only one who provides a fascinating template for actors and a rich personal history for the audience. The character of Ophelia has been cause for particular debate among audiences, readers and critic - visit this page for an examination of what we can learn about fictionalized madness, gender, and changing conceptions of female sexuality, read this visual essay on some iconic depictions of Ophelia in art (find more on this topic here), and this personal essay on the author's love of Ophelia as unlikely icon.

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Why should you read "Hamlet"? - Iseult Gillespie

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"Who's there?" Whispered in the dark, this question begins a tale of conspiracy, deception and moral ambiguity. And in a play where everyone has something to hide, its answer is far from simple. Written by William Shakespeare, "Hamlet" depicts its titular character haunted by the past, but immobilized by the future.

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Witches and witch hunting are popular subjects in our media these days, but much of what movies, television, and books offer is misleading and misinformed. It is fun to make up stories about magic and witchcraft. But the actual history shows a harsh reality of governments persecuting and killing tens of thousands of people for a crime they did not commit. And the historical facts can seem even more bizarre than many fictional stories, including accounts of the most strange activities blamed on witches, demons, and the Devil.

Of course, issues of witchcraft are not mere past history. Many people today believe in witches, demons, and the Devil, although their beliefs rarely align with those of the time of the witch hunts, from the fifteenth to the eighteenth century. In some places in the world today, people are being persecuted as accused witches, although these actions are not quite defined as "hunts" since the government is not involved.

More information about how historians are trying to understand the problem of witch hunting can be found at this website. It includes some discussion about perceptions of historians and links to fairly reliable information on the web. Students can also find some links to primary sources, including translations of letters written by and for Rebecca Lemp, or even take an online simulation of a hunt. With the right choices, and luck, your character might survive! TED-Ed lessons on the Salem Witch Hunt and the Devil offer short overviews of a specific hunt and perspectives on how people have understood the Devil.

For a short, readable book on the Witch Hunts, try Brian A. Pavlac, Witch Hunts in the Western World: Persecution and Punishment from the Inquisition through the Salem Witch Trials Greenwood 2009 or Bison Books 2010.

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Ugly History: Witch Hunts - Brian A. Pavlac

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In the German town of Nördlingen in 1593, innkeeper Maria Höll found herself accused of witchcraft. She was arrested for questioning, and denied the charges. She insisted she wasn't a witch through 62 rounds of torture before her accusers finally released her. Other accused witches weren't so "lucky."

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Emerging viral diseases are often the product of a host shift, where a pathogen jumps from its original host into a novel species. Studies have shown that host shifts are a common in the evolution of most pathogens, but why pathogens can successfully jump between some host species but not others is only just becoming clear. The susceptibility of potential new hosts can vary enormously, with close relatives of the natural host typically being the most susceptible. Often, pathogens must adapt to successfully infect a novel host, for example by evolving to use different cell surface receptors, to escape the immune response, or to ensure they are transmitted by the new host. If you'd like to read more about host shifts in the scientific literature, these review articles are a good place to start: here and here.

If you are interested in how pathogens spread, and why they cause harm, you could look at this other excellent TED-Ed video on how germs spread and how they make us sick.

For some of the issues around predicting the next big epidemic in humans you could read this article.

We have developed a game called Viruscraft that is based on research about host shifts - you play as a virus and have to add receptors to a virus to help it spread both within and between species.

For more on the ubiquity of viruses and viral epidemics in a pop-science format see "A Planet of Viruses" by Carl Zimmer

For an overview of the research we've carried out on host shifts using an insect-virus model system see this website.

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How do viruses jump from animals to humans? - Ben Longdon

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At a Maryland country fair in 2017, farmers reported feverish hogs with inflamed eyes and running snouts. While farmers worried about the pigs, the department of health was concerned about a group of sick fairgoers. Soon, 40 of these attendees would be diagnosed with swine flu.

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The secret student resistance to Hitler - Iseult Gillespie

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In 1943, Allied aircraft rained tens of thousands of leaflets on Nazi Germany below. The leaflets urged readers to renounce Hitler, to fight furiously for the future— and to never give up hope. Their call to action rippled through homes and businesses— and their message even reached concentration ca…

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The people behind the search for the origin of life
The first person to really explore the origin of life was Francesco Redi. In the 17th h century he experimentally proved that maggots did not spontaneously generate in rotting meat. This experiment was the first to reject the idea of spontaneous generation of life. Today, scientists are applying the concepts, tools and questions, used to understand the origin of life on Earth, in order to find life in the extraterrestrial universe

If "all life emerged from an egg", as Francesco Redi put it, where lies the true origin of life? This question inspires many scientists to this day. In the late 19 th century, the British naturalist Charles Darwin envisioned " some warm little pond " as the place where life originated.

In the early 20 th century, J.B.S. Haldane and Alexander Oparin independently developed the hypothesis that life originated in a primordial soup enveloped by an atmosphere rich in methane and ammonia. This became known as the Oparin-Haldane hypothesis and was empirically tested by Harold Urey and his student Stanley Miller. The Miller-Urey experiment proved that organic compounds could be generated from inorganic substances with the help of electric sparks. However, the problem with this experiment is that the primordial atmosphere was like ours today, just with a lot more carbon dioxide and no oxygen.

The chemical compounds necessary to life needed to be derived from somewhere other than the atmosphere. In addition, it was suggested that volcanic eruptions and UV radiation made it impossible for life to form on the Earth's surface. But it was also clear that the first living organism had to be an autotroph like plants, which are only found in sunlight.

These two seemingly contradicting requirements for the origin of life were resolved when, diving in the DSV Alvin, oceanographer Jack Corliss and his team discovered hydrothermal vents at the Galápagos Rift. These black smokers provided a chemical gradient that was harnessed by microbial autotrophs in a process called chemosynthesis.

Since their discovery in the 80s, many marine scientists have been studying deep sea hydrothermal vents. Notable scientists that pushed for the recognition of hydrothermal vents as the cradle of life include Günter Wächtershäuser, Robert Hazen, William Martin and Gretchen Früh-Green. The latter lead the discovery of Lost City and has since been at the forefront of studying this alkaline vent system.

Diversity at hydrothermal vents and why the deep sea needs protection
Hydrothermal vents are true biodiversity hotspots in the deep sea. Alkaline vents like Lost City were initially thought to be devoid of life, until its diverse microbial community was discovered. Black smokers boast a conspicuous array of fascinating animals. These include giant red tube worms called Riftia pachyptila, which rely entirely on symbiotic chemoautotrophic bacteria
for nourishment, white skates called Bathyraja spinosissima, which lay their eggs near black smokers, giant mussels called Bathymodiolus thermophilus, and white crabs in the family Bythograeidae.

The Lost City hydrothermal vent field was declared open to deep sea mining by the International Seabed Authority last year. Hydrothermal vents are considered to harbor high concentrations of precious minerals. With the globally increasing demand for smartphones, and the plethora of rare minerals contained within them, investors are looking for new ways to acquire these resources in large quantities. Many other devices, considered to be part of modern everyday life, like computers and electric cars, require rare elements as well. This high demand is driving the development of deep sea mining rovers and we can expect mining operations targeted at the Earth's largest ecosystem in the near future.

Mining is not the only human impact on the deep sea. Deep sea fishing is thought to have tremendous impacts because trawling destroys a wide range of benthic habitats. Most notoriously, the orange roughy (Hoplostethus atlanticus) is fished on a large scale. Ironically, the fishery exploiting the orange roughy, which is listed on the IUCN endangered species list, was recently certified as sustainable by the Marine Stewardship Council.

With a globally increasing need for oil and gas, deepwater drilling is becoming increasingly common, with known consequences. Many nations have been trying to extend their deep sea territory through existing laws and loopholes, in order to claim more resources. The most famous example is the " Arctic resources race". With adequate foresight and by planning conservation strategies it is possible to manage these natural resources in the deep sea.

Unfortunately, the current money-driven race for the exploitation of the deep sea is lacking required planning and conservation policy. However, many marine scientists are striving to discover much that yet lies in the unknown depths of the ocean. Do we want to lose these fascinating and mysterious ecosystems before we can even attempt to fully understand them?

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The mysterious origins of life on Earth - Luka Seamus Wright

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Billions of years ago, simple organic compounds assembled into more complex coalitions that could grow and reproduce. At the time, Earth had widespread volcanic activity and a hostile atmosphere that made it almost devoid of a suitable environment for living things. So where did life begin?

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Let's Begin...

In the 1980s and 90s, pharmaceutical companies began to market opioid painkillers aggressively, while actively downplaying their addictive potential. The number of prescriptions skyrocketed, and so did cases of addiction, beginning a crisis that continues today. What makes opioids so addictive? Mike Davis explains what we can do to reverse the skyrocketing rates of addiction and overdose.

Create and share a new lesson based on this one.

About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here "

Meet The Creators

Educator Mike Davis

Director Kunal Sen, Tisha Deb Pillai

Narrator Addison Anderson

Art Director Kunal Sen

Storyboard Artist Tisha Deb Pillai

Music Landon Trimble / Playdate

Director of Production Gerta Xhelo

Editorial Producer Alex Rosenthal

Producer Bethany Cutmore-Scott

Associate Editorial Producer Elizabeth Cox

Script Editor Emma Bryce

Fact-Checker Eden Girma

See more creators

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What causes opioid addiction, and why is it so tough to combat? - Mike Davis

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In the 1980s and 90s, pharmaceutical companies began to market opioid painkillers aggressively, while actively downplaying their addictive potential. The number of prescriptions skyrocketed, and so did cases of addiction, beginning a crisis that continues today. What makes opioids so addictive? Mike Davis explains what we can do to reverse the skyrocketing rates of addiction and overdose.

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In the soil beneath your feet, a diverse array of microbes is at work around, on and in tree roots. This microscopic world includes intimate partnerships, or symbiosis, between tree fine roots and soil fungi called mycorrhizae. Mycorrhizal fungi partner with the root, creating exchange sites where the tree can trade energy it gets from photosynthesis with resources acquired from the soil by fungi. The mycorrhizal fungi collect these resources with branching mats of thread-like material called mycelium. This extensive mycelium can also connect the roots of different trees forming mycorrhizal networks. These networks are considered ecologically and evolutionarily important because they influence the survival, growth, physiology, health, competitive ability and behaviour of the plants and fungi linked in them. How do we know that? Watch Prof. Suzanne Simard's TEDSummit talk, TEDxSeattle talk, or TED-Youth NewOrleans talk to learn about her groundbreaking scientific discoveries that she has been making in the Canadian Wilderness since the 1990s. Also watch for her upcoming book, Finding the Mother Tree, to be published in 2020 by Penguin Random House. You can further Watch BBC news to know how some plants use mycorrhizal networks to support their offspring while others hijack it to sabotage their rivals. Does it remind you of a sort of intelligence? You may think "how can you be intelligent without a brain?" Well, let's dive underground while watching the award-winning film "Intelligent Trees" or listening to the podcast "From Tree to Shining Tree" of the Radiolab. If you want to know how are humans impacting mycorrhizae, and how can we conserve these important symbioses, learn about The Mother Tree Project and send an email to our website. Do you want to know how conserving mycorrhizal fungi could help Canada's vast boreal and tundra ecosystems to thrive as our climate warms? Check out the work of Dr. Brian Pickles and Dr. Jason Pither. You can also learn from First-Nation's wisdom who have deep connections with forests. Watch Dr. Teresa Ryan's TEDx talk where she tells us about her ancestral legacy of nature's connections or during your trip to Canada, go take a look at Tania Willard's artwork, exhibited in the busiest SkyTrain station of the city of Vancouver. If you want to know more about current researches on roots and mycorrhizal fungi in British Columbia, watch the video of Camille Defrenne and Julia Amerongen Maddison or browse through the Simard's lab website!

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The secret language of trees - Camille Defrenne and Suzanne Simard

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Most of the forest lives in the shadow of the giants that make up the highest canopy. These are the oldest trees, with hundreds of children and grandchildren. They check in with their neighbors, share food, supplies and wisdom gained over their lives, all while rooted in place.

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Vultures are real life superheroes. Often portrayed as the villains, vultures are not only the clean-up and sanitation crew, they are also saving lives. Learn why 50% of all vulture species are endangered and how you can help. Kenny Coogan explores how vultures transform death and decay into life.

Have no fear, vultures are here. We need vultures and much as they need us now. With 50% of all vulture species endangered, there is a vulture crisis.

Vultures play a vital ecological niche in the habitats where they live. In regions of the world where vultures are being killed, incidents of humans with rabies have increased. In India, where nine species of vultures are now endangered, tens of thousands of people die of rabies annually. Although vultures have stomachs of steel and can safely eat diseased meat that contain anthrax, pneumonia, and rabies, vultures face a range of threats in many areas that they inhabit. Much of this is caused by poachers poisoning carcasses to prevent the vultures tipping off park rangers to the death of protected rhinos or elephants. Vulture species are under pressure and many species are facing extinction. We need to save these superheroes, so in turn they can save us.

To celebrate these scavengers, check out International Vulture Awareness Day events in your area.

Kenny Coogan, the educator of this TED-Ed animation, has admired and worked with vultures for many years. Visit his website to learn more and to check out painted feather which highlight vultures.

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Vultures: The acid-puking, plague-busting heroes of the ecosystem - Kenny Coogan

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In the African grasslands, a gazelle suffering from tuberculosis takes its last breath. The animal's corpse threatens to infect the water, but for the vulture, this isn't a problem: it's a feast. With a stomach of steel that can digest diseased meat and waste, vultures are essential to removing dangerous pathogens from ecosystems. Kenny Coogan explores the importance of the desert's cleanup crew.

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Throughout history, paradoxes have threatened to undermine everything we know, and just as often, they've reshaped our understanding of the world. Today, one of the biggest paradoxes in the universe threatens to unravel the fields of general relativity and quantum mechanics: Fabio Pacucci describes the black hole information paradox.

Following the definition of the authoritative Oxford English Dictionary, a paradox is "a statement or proposition which, despite sound (or apparently sound) reasoning from acceptable premises, leads to a conclusion that seems logically unacceptable or self-contradictory". The word comes from the Greek "paradoxon" which means "contrary to the opinion". Throughout the history of Science, paradoxes have many times sparkled new ideas, or even new fields. For example, in ancient times the paradox of Achilles and the tortoise triggered interest in infinitesimals.

In this dig deeper section, I will describe three very famous scientific paradoxes that have helped in advancing scientific knowledge in the fields of physics, mathematics and astronomy. I will describe each paradox and clarify why it is (at least apparently) self-contradictory. The readers are very encouraged to try and find a solution to these paradoxes on their own, or look for it on the online resources provided here.

Achilles and the Tortoise Paradox - This is likely one of the best known paradoxes of all times, although it is just one representation of a more general paradox of classical mechanics, usually named " Zeno's paradox of motion ", from the name of the Greek philosopher and mathematician born around 495 BCE in the current south of Italy. In Greek mythology, Achilles was the strongest warrior of the Greek army of Agamemnon in the famous Trojan war. We all know that Achilles must be way faster than a slow-moving, peaceful tortoise. Now, assume that Achilles and a tortoise are up for a race, and the tortoise is given a little, finite, advantage ahead of the starting line. Both Achilles and the tortoise begin to run at the same time. By the time Achilles reaches the position that was previously occupied by the tortoise, the latter will have advanced by a small step. Once Achilles reaches this new position, the tortoise would have advanced further. Hence, the separation between the tortoise and Achilles would constantly decrease, but never reach zero. So the tortoise will eventually... win! Of course, we all know this is not true (otherwise, following Zeno, all motion would be impossible!) and Achilles will, alas, always win. So, where is the trick?

Infinite Hotel Paradox - This paradox, or thought experiment, deals with the counter-intuitive properties of infinite sets and was devised by the German mathematician David Hilbert in 1924. Assume the existence of a hotel named "Infinity". This hotel has the remarkable property of having an infinite number of rooms, numbered 1, 2, 3... up to infinity. Luckily for the owner of this hotel, all its rooms are occupied by an infinite number of guests. An additional individual shows up at the reception, asking for a room. Can we accommodate the newly arrived person? What happens if one, infinitely long, bus with an infinite number of prospective new guests arrives? Can we accommodate all of them? And what if an infinite number of buses, each of them with an infinite number of prospective new guests, arrives? Can we still accommodate them? The answer to all these questions is yes. The real problem is... how?

The Olbers' Paradox - This paradox was formulated by the XVIII century German astronomer Heinrich W. Olbers and proved to be fundamentally important for the development of the study of the Universe as a whole, or Cosmology. The paradox originates from the very simple observation that the night sky is dark. We all know this for a fact, but this observation is troubling in case we assume the Universe to be infinite, thus containing an infinite amount of stars. If this were to be true, then any line of sight would encounter, sooner or later, the surface of a star, close-by or far away. Hence, the night sky should not be dark at all, rather should be as bright as the surface of our Sun. Quite surprisingly, it is not even sufficient to assume that the Universe is finite to solve the paradox. So, where is the trick? The final solution was firstly hinted at by the American writer Edgar Allan Poe (!) in his poem Eureka and then completely solved by the development of the Big Bang Theory.

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Hawking's black hole paradox explained - Fabio Pacucci

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Today, one of the biggest paradoxes in the universe threatens to unravel modern science: the black hole information paradox. Every object in the universe is composed of particles with unique quantum properties and even if an object is destroyed, its quantum information is never permanently deleted.

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The goddess Isis faced many challenges and dangers. But one particular episode reveals her dual nature as both a fearsome and merciful figure.

As in much of Egyptian mythology, representations of Isis and Serket vary between sources. The legend of the scorpions has been retold by scholars like James Frazier and Margaret Murray; Isis also plays a major role in the collection of funerary texts known as the Book of the Dead. Another well-known myth involving Isis and Ra can be found here.

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The Egyptian myth of Isis and the seven scorpions - Alex Gendler

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A woman in rags emerged from a swamp flanked by seven giant scorpions and approached a magnificent mansion to beg for food. But the mistress of the house took one look at her grimy clothes and unusual companions and slammed the door in her face.

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Epic Engineering: Building the Brooklyn Bridge - Alex Gendler

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In the mid-19th century, suspension bridges were collapsing all across Europe. Their industrial cables frayed and snapped under the weight of their decks. So when German American engineer John Roebling proposed building the largest and most expensive suspension bridge ever conceived, New York City o…

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It's one of Italy's most iconic tourist attractions. But why does the Tower of Pisa lean, and how is it still standing?

Learn more about the famous tower, including visitor info, take a virtual tour, or read the account from the American soldier who narrowly spared it from bombing. For more technical details, check out this timeline of the tower's construction, this civil engineering report on the stabilization work, or this detailed overview of historical and modern attempts at stabilization.

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Why doesn't the Leaning Tower of Pisa fall over? - Alex Gendler

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In 1990, the Italian government enlisted top engineers to stabilize Pisa's famous Leaning Tower. There'd been many attempts during its 800 year history, but computer models revealed the urgency of their situation. The tower would topple if it reached an angle of 5.44 degrees- and it was currently leaning at 5.5.

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The Norse gods hired a mysterious stranger to build a massive wall around their home of Asgard... but at what cost?

Read the original account of this myth in the Prose Edda, and the related part of the Poetic Edda. Or check out Neil Gaiman's lively retelling of the story, and learn more about the background of Norse mythology.

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The myth of Loki and the master builder - Alex Gendler

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Asgard, a realm of wonders, was where the Norse Gods made their home. There Odin's great hall of Valhalla towered above the mountains and Bifrost, the rainbow bridge, anchored itself. Though their domain was magnificent, it stood undefended from the giants and trolls who sought to destroy them.

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The attacking infantry advances, their elephants already having broken the defensive line. The king tries to retreat, but the enemy flanks him from the rear. Escape is impossible. This isn’t a real war— nor is it just a game. Over the 1,500 years of its existence, chess has been known as a military strategy tool, a metaphor for human affairs and a measure of genius. Alex Gendler shares its history.

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Educator Dan Reinsten

Director Luísa Holanda

Narrator Addison Anderson

Art Director Luísa Holanda

Storyboard Artist Luísa Holanda

Illustrator Luísa Holanda

Character Designer Luísa Holanda

Editor Bruno B Kieling

Senior Animator Bruno B Kieling

Producer Taíla Soliman, Cristina Arikawa, Mauricio Brunner , Gabriel Garcia

Production Assistant Victoria Farina

Director of Production Gerta Xhelo

Editorial Producer Alex Rosenthal

Associate Producer Bethany Cutmore-Scott

Associate Editorial Producer Dan Kwartler

Script Editor Eleanor Nelsen

Fact-Checker Joseph Isaac

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How does laser eye surgery work? - Dan Reinstein

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In 1948, Spanish ophthalmologist Jose Ignacio Barraquer Moner was fed up with glasses. He wanted a solution for blurry vision that fixed the eye itself, without relying on external aids. The surgery he eventually devised was called "keratomileusis," and his technique focused on reshaping the cornea- what we now know as LASIK.

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The first and last king of Haiti - Marlene Daut

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The royal couple of Haiti rode into their coronation to thunderous applause. After receiving his ornate crown, Henry Christophe ascended his throne, towering 20 meters in the air. But little did the cheering onlookers know that the first king of Haiti would also be its last. Who was this revolutiona…

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Let's Begin...

It's an incredible discovery: an abandoned alien space station filled with precursor technology. Now every species in the galaxy is in a mad dash to get there first, but you've got a problem. Your ship can't hold enough fuel to get you there unless you vent caches of it into space at precise points and then come back for the fuel later. Can you reach the alien space station? Dan Finkel shows how.

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About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here "

Meet The Creators

Educator Daniel Finkel

Director Igor Coric

Narrator Addison Anderson

Animator Nemanja Petrovic

Sound Designer Nemanja Petrovic

Director of Production Gerta Xhelo

Editorial Producer Alex Rosenthal

Associate Producer Bethany Cutmore-Scott

Fact-Checker Eden Girma

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Can you solve the dark matter fuel riddle? - Daniel Finkel

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It's an incredible discovery: an abandoned alien space station filled with precursor technology. Now every species in the galaxy is in a mad dash to get there first, but you've got a problem. Your ship can't hold enough fuel to get you there unless you vent caches of it into space at precise points and then come back for the fuel later.

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Lord of the Flies is a work of fiction--but history has seen people in real life act in similar ways to the boys in the story. In 1971, professors at Stanford University conducted a simulation of prison life in what has come to be known as the Stanford Prison Experiment. In the experiment, undergraduate students signed consent forms and waivers, agreeing readily to be subjected to life as a prisoner for two weeks. Within twenty-four hours, both "prisoners" and "guards" began acting as if they were not in an experiment at all, but truly in positions of disenfranchisement and power, respectively. Even the researchers became so absorbed in the experiment that their realities were distorted. In fact, the study did not run its full two-week course as planned, but was cut short after only six days. The Stanford Prison Experiment illustrates a belief Golding held, that humans are inherently capable of committing heinous acts, that power can corrupt even the most ordinary people, and that mob mentality rules. Read more about the Stanford Prison Experiment here.

In 1963, filmmaker Peter Brook adapted Golding's first novel into a feature-length film. He filmed in Puerto Rico, on the mainland as well as a small island called Vieques. Hiring amateur actors, Brook and his crew housed the boys in former US Navy quarters and finished filming within three months, then spent a year editing. The film is quite true to the original, with some scenes improvised or filmed with very little direction. Brook recalls that the offscreen dynamics between the actors sometimes eerily paralleled those of the characters in the story, noting that the boy who played Piggy was told that one particular scene would be his last. Further, Brook posits that "[Golding's] action takes about three months. I believe that if the cork of continued adult presence were removed from the bottle, complete catastrophe could occur within one long weekend." Read more about the making of the film here (be warned of spoilers).

Golding's views were shaped by his own experiences, and it is understandable that he might take a dismal view of humanity after witnessing the horror of war. We can choose to agree with Golding that " man produces evil as a bee produces honey," or follow Anne Frank's lead and believe that "people are truly good at heart." The 21st century has seen mass shootings, natural disasters, terrorist attacks, and the escalation of foreign conflicts. Examples of the worst of humanity, these tragedies have also brought out the very best in people. 2017 saw an increase in charitable giving, to more than $390 Billion. Volunteers from around the world flocked to cities plagued by natural disasters, and social media campaigns have raised awareness of global issues with effective hashtags. After a hate-motivated shooting at a Christchurch, NZ mosque in early 2019, members of the community offered to guard the building at the next week's prayers but were instead invited to join the service. When a tornado leveled parts of Kansas in 2019, a group of civilians stepped in as the "Cajun Navy" to help lead recovery efforts. These are just a few examples of many, illustrating that while people can be cruel and inhumane, there is great capacity for good in the world, as well. Golding's novel can serve as a cautionary story, reminding us that we can choose how we respond when people showcase the worst of themselves.

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Why should you read "Lord of the Flies" by William Golding? - Jill Dash

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After witnessing the atrocities of his fellow man in World War II, William Golding was losing his faith in humanity. Later, during the Cold War, as superpowers began threatening one another with nuclear annihilation, he was forced to interrogate the very roots of human nature and violence.

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Let's Begin...

Bones might seem rock-solid, but they're actually quite porous inside. Most of the large bones of your skeleton have a hollow core filled with soft bone marrow. Marrow's most essential elements are blood stem cells and for patients with advanced blood cancers like leukemia and lymphoma, the best chance for a cure is often a bone marrow transplant. How does this procedure work? Melody Smith explains.

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About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here "

Meet The Creators

Educator Melody Smith, Melody Smith

Director Igor Coric, Igor Coric

Narrator Bethany Cutmore-Scott, Bethany Cutmore-Scott

Animator Igor Coric

Storyboard Artist Igor Coric

Art Director Igor Coric

Sound Designer Cem Misirlioglu

Director of Production Gerta Xhelo

Editorial Producer Alex Rosenthal

Producer Bethany Cutmore-Scott

Script Editor Eleanor Nelsen

Fact-Checker Laura Shriver, Joseph Isaac

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Bones might seem rock-solid, but they're actually quite porous inside. Most of the large bones of your skeleton have a hollow core filled with soft bone marrow. Marrow's most essential elements are blood stem cells and for patients with advanced blood cancers like leukemia and lymphoma, the best chance for a cure is often a bone marrow transplant.

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Let's Begin...

Feeling disconnected from creating art within classical conventions, artist Georgia O'Keeffe began experimenting with abstract drawings that defied easy classification. Using the shapes and rhythms of nature to capture her internal world, these experiments became the cornerstone of the movement known as American Modernism. Iseult Gillespie explores the works of the elusive painter and sculptor.

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About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here "

Meet The Creators

Educator Iseult Gillespie

Director Lisa LaBracio

Narrator Christina Greer

Animator Lisa LaBracio

Music M. Tomihisa

Sound Designer M. Tomihisa

Director of Production Gerta Xhelo

Editorial Director Alex Rosenthal

Producer Bethany Cutmore-Scott

Editorial Producer Dan Kwartler

Fact-Checker Alejandra Vasquez

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How to see more and care less: The art of Georgia O'Keeffe - Iseult Gillespie

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Feeling disconnected from creating art within classical conventions, artist Georgia O'Keeffe began experimenting with abstract drawings that defied easy classification. Using the shapes and rhythms of nature to capture her internal world, these experiments became the cornerstone of the movement known as American Modernism. Iseult Gillespie explores the works of the elusive painter and sculptor.

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In the year 1692, the worst witch hunt in American history broke out in Salem, a town in the Massachusetts colony. The Puritan colonists put on trial neighbors whom they imagined were working with the Devil to cause harm. Brian A. Pavlac relates what happened in this hunt to punish imaginary witches.

Salem was just one small, brief persecution at the end of the period from the fifteenth to the eighteenth century when Christians actively hunted witches. In Europe and the American colonies during this time, tens of thousands of people suffered from a panic-stricken pursuit of alleged devil-worshipping witches. Unfortunately, no decent historical evidence exists for magic and the supernatural, whether for harm or for good. The history of Salem shows the grim consequences of family, neighbors, church, and government mistakenly persecuting people for a crime they could not possibly have committed.

Instead of actual proof, fearful authorities in Salem relied on unsubstantiated accusations, rumor, innuendo, torture, and, most tragically, "spectral evidence." The last allowed a gaggle of girls in open court to make up ghostly attacks, which they blamed on the accused. As a result, jurors and judges condemned nineteen men and women to be hanged by strangulation (there were no executions by burning at Salem), one man to be pressed to death for refusing to plead guilty or not guilty, and two dogs to be shot. Imprisonment also led to deaths and illnesses for many others. A few years after this panic collapsed, the embarrassed government actually paid compensation to survivors and families of the dead.

Of course, issues of witchcraft are not just events from the past. Many people today still believe in witches, demons, and the Devil, although their beliefs rarely align with those at Salem or from the time of the witch hunts. In some places in the world today, people continue to be accused and persecuted as witches, although these actions are not usually defined as "hunts" since the government is not involved. That distinction, however, is surely of little consolation for the victims.

A brief overview of witch hunting based on a German incident is available with this TED-Ed video, "Ugly History: Witch Hunts" . More information about how historians are trying to understand the general problem of the witch hunts can be found at this website. It also offers links to many online sources on Salem. More about the Devil can be found in the TED-Ed lesson, Three Faces of the Devil.

For a short, readable book on the Witch Hunts, try Brian A. Pavlac, Witch Hunts in the Western World: Persecution and Punishment from the Inquisition through the Salem Witch Trials ( Greenwood 2009 or Bison Books 2010).

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What really happened during the Salem Witch Trials - Brian A. Pavlac

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You've been accused of a crime you did not commit. It's impossible to prove your innocence. If you insist that you're innocent anyway, you'll likely be found guilty and executed. But if you confess, apologize, and implicate others, you'll go free. This was the choice facing those accused of witchcraft in Salem, Massachusetts in the 17th century.

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The rise of modern populism - Takis S. Pappas

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In many democratic countries, charismatic leaders vilify political opponents, disparage institutions, and claim to be for the people. Some critics label this approach as authoritarian or fascist, while others argue that these leaders are manipulating voters. This style of politics goes by the name of populism. Takis S.

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The mission to send a person to the Moon and have them return to Earth safely required the invention of not only new technologies, but new ways of approaching scientific problems. In her effort to help astronauts get to the Moon safely, Margaret Hamilton invented the new field of "software engineering." How did her work help Neil Armstrong and Buzz Aldrin land on the Moon?

The on-board flight software team led by Margaret Hamilton developed the software on the Apollo Guidance Computer (AGC) that took humans to the moon and back.

The software was developed by the software people, a new breed of engineer. The task at hand for the software people (the "software engineers"): develop the software for the Command Module (CM), the Lunar Module (LM) and the systems software (used by and residing in both the CM and the LM). The systems software included the design and development of the error detection and recovery programs such as restarts and the Display-Interface-Routines' Priority Displays. The software engineers created the overall design of the software structure (the "glue") that held everything together as an integrated system of systems.

Updates were continuously being submitted into the software over time and over many releases for each and every mission (when software for one mission was often being worked on concurrently with software for other missions); making sure everything would play together and that the software would successfully interface to and work together with all the other systems for each mission.

Because the onboard flight software for the manned missions was asynchronous, it had the flexibility to handle the unpredictable: higher priority jobs interrupted lower priority jobs, based on events as they happened. It was up to the team to determine the relative importance of each process and to assign to it a unique priority to ensure that all events would occur in the correct order and time relative to everything else going on.

The Priority Displays interface routines gave the software the ability to communicate asynchronously in real time with the astronauts. For the first time, the new displays warned the astronauts in the case of an emergency by interrupting their normal mission displays and replacing them with priority alarms. Just before landing on the moon, the Apollo 11 computer, as a result of the rendezvous radar switch having been left on, became overloaded. The priority alarm displays were a reminder to the astronauts to put the radar switch back to where it belonged.

Since it was not possible (certainly not practical) on Apollo to test the software "before the fact" by "flying" an actual mission, it was necessary to test the software by developing a mix of hardware and digital simulations of every (and all aspects of an) Apollo mission which included man-in-the-loop simulations (with real or simulated human interaction); and variations of real or simulated hardware and their integration in order to make sure that a complete mission from start to finish would behave exactly as expected.

Margaret Hamilton called the development of the AGC an "opportunity of a lifetime." She said, "We were handicapped by the computer's time and space constraints, giving "software experts" the license to be "creative", resulting in tricky programming. Requirements were "thrown over the wall" by "non-software experts" who assumed that all the software programs would somehow "magically" interface together. Fortunately, this was not the case. For, if it had been, we would never have learned what we did about errors and how to prevent them.

Although there were more than enough opportunities to make errors, there were now the opportunities to come up with new ways to prevent them. We evolved " software engineering " rules and techniques with each relevant discovery. Although many errors were found during the software's pre-flight phases, no software errors were known to have occurred during flight on any of the Apollo missions.

Against the backdrop of the Cold War conflict, a new kind of rivalry took shape in the early 1960s between the United States and the Soviet Union. The Russians appeared to be ahead in the so-called "race for space" as they followed their launching of the first satellite, Sputnik, in 1957 with the history-making flight of cosmonaut Yuri Gagarin in April 1961. In 1962 at Rice University, President Kennedy called for the landing of an American on the moon by the end of the decade as he sought a major mobilization of the nation's resources to catch up with and surpass the USSR in the space race.

President Kennedy understood the need to restore America's confidence and intended not merely to match the Soviets, but surpass them. On May 25, 1961, he stood before Congress to deliver a special message on "urgent national needs." He asked for an additional $7 to $9 billion over the next five years for the space program, proclaiming that the nation should commit itself to landing a man on the Moon and returning him safely to the earth by the end of the 1960s. President Kennedy settled upon this dramatic goal as a means of focusing and mobilizing the nation's lagging space efforts.
On July 20, 1969, the Apollo 11 astronauts-Neil Armstrong, Michael Collins, and Edwin "Buzz" Aldrin Jr.-realized President Kennedy's dream.

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NASA's first software engineer: Margaret Hamilton - Matt Porter and Margaret Hamilton

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The Apollo 11 moon landing was about the astronauts, mission control, software and hardware all working together as a seamless integrated system. None of which would have been possible without the contributions of one engineer: Margaret Hamilton. Who was this pioneer?

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Penicillin is a well-known and widely used antibiotic. How was penicillin discovered? How does it work against bacteria? What threatens its efficacy against infections?

If you're interested a few more details about how penicillin works, check out this video from the Food and Drug Administration (FDA video)

The American Board of Internal Medicine has a campaign of smart practices across all medical specialties. Recommendations surrounding penicillin allergy can be found here

The Centers for Disease Control has a fact sheet about penicillin and penicillin allergy.

Check out the American College of Allergy, Asthma & Immunology's drug allergy guide to learn about different symptoms to drug allergies.

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The accident that changed the world - Allison Ramsey and Mary Staicu

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In 1928, scientist Alexander Fleming returned to his lab and found something unexpected: a colony of mold growing on a Petri dish he'd forgotten to place in his incubator. And around this colony of mold was a zone completely and surprisingly clear of bacteria. What was this mysterious phenomenon?

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A Dutch art forger managed to fool the world's leading experts, and even dupe Nazi leader Hermann Goring. But when he was arrested, he had to un-fool the world by proving that he was, in fact, a forger and had not traded original masterpieces to the enemy-with his life on the line should he fail. This strangest of courtroom dramas shows that some crimes do pay, both in cash and notoriety, and that even a proven forger can become a popular folk hero.

big illustrated book, The Art of Forgery.
This book is the complete story and analysis of how criminals have successfully passed off forgeries, primarily in the world of art, but also beyond (covering things like religious relics, natural history specimens, and even rare wine). It is a psychological analysis of forgers with a focus also on their forensic techniques and, of course, fascinating stories.

Did this forger actually want smarter art experts?
The story of Eric Hebborn, in my opinion the greatest of all art forgers, is particular in that he was never caught, but "came out" as it were by publishing a book called "The Art Forger's Handbook" which laid out his techniques-and a copy of which has been found in the homes of many forgers since then.

Foiling the Forgers: Giacommeti
The case study of John Myatt and John Drewe provides an example of one of the "provenance traps" successfully used by forgers, in this case to pass of works purportedly by Giacometti.

Foiling the Forgers: Matisse
This case study looks at the forgery of a Matisse painting. Once the star of a major museum in Venezuela, the painting at some point was stolen and an excellent forgery swapped in its place. It took years for anyone to notice.

Foiling the Forgers: Dali
The story of Salvador Dali forgeries is distinctive because Dali endorsed the forger, and the forgeries were coming out of his studio, with his signature. Does this make them forgeries or merely a product of an artist's studio system?

How to Navigate the Art Market
The art world can be a confusing place, and it really is a striking, murky organism in which criminality can thrive. This article offers insight for collectors on how to navigate these often-choppy waters.

David Bowie's Great Art Hoax
Among David Bowie's many accomplishments, few know that he was involved in an elaborate practical joke on the art world in which he and a famous novelist invented an artist, published a book about him, and then were delighted when many people "remembered" having met him.

On Alec Baldwin, Bait-and-Switches and Original Copies
Alec Baldwin was one of many celebrities who were victimized by art swindles. This article looks at how he was fooled and what mechanism the forger used to pull it off.

Are Replicas Changing the Way We Experience Art?
Modern technology allows for the production of replicas that are all-but-indistinguishable from originals. This article looks at how this is done, and whether it changes the way we experience art.

How Not To Buy Stolen, Looted or Forged Art
Written as a guide for the art fair season, this article helps potential buyers to be aware of how to avoid acquiring problematic (forged, stolen or looted) art.

A Fake of Art
This article looks at issues in authenticity and the role of museums in being open about replicas that they display in lieu of originals

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The art forger who tricked the Nazis - Noah Charney

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It was one of the strangest trials in Dutch history. The defendant in a 1947 case was an art forger who had counterfeited millions of dollars worth of paintings. But he wasn't arguing his innocence- in fact, his life depended on proving that he had committed fraud.

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Sigmund Freud is considered one of the most important thinkers of the 20th century, famous not only for inventing the 'talking cure' called psychoanalysis, but for his impact of society more generally. Yet his therapy has been eclipsed by psychopharmacology and shorter term treatments, and his cultural influence has waned. What, if anything, is worth saving from psychoanalysis?

Interested in reading Freud's work for yourself? Checkout his published work online in the links below:
- https://onlinebooks.library.upenn.edu/webbin/book/lookupname?key=Freud%2C+Sigmund%2C+1856-1939

- https://www.valas.fr/IMG/pdf/Freud_Complete_Works.pdf

I a lot of work has been produced to rethink psychoanalysis. Check out literature on about rethinking psychoanalysis

Borch-Jacobsen, Mikkel (2012). "Freud's Patients, A Serial," Psychology Today. See https://www.psychologytoday.com/ca/blog/freuds-patients-serial

Dufresne, Todd (2004). "Psychoanalysis is Dead - So How Does That Make You Feel?" The Los Angeles Times (Feb 18). See https://www.latimes.com/archives/la-xpm-2004-feb-18-oe-dufresne18-story.html
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(2017). "Reflections on Freud, The First 'Wild Analyst', Oxford Childhood Studies at Oxford University Press Blog (May 6). See https://blog.oup.com/2017/05/freud-first-wild-analyst/

Gopnik, Adam (1998). "Man Goes to See a Doctor," The New Yorker (August 17). See https://www.newyorker.com/magazine/1998/08/24/man-goes-to-see-a-doctor

Still Debating Freud?

Menand, Louis (2017). "Why Freud Survives," The New Yorker (August 21). See at https://www.newyorker.com/magazine/2017/08/28/why-freud-survives

"How We Feel About Freud: Susie Orbach and Frederick Crews Debate His Legacy," The Guardian (August 20, 2017). See https://www.theguardian.com/books/2017/aug/20/feel-about-freud-debate-frederick-crews-susie-orbach-making-of-an-illusion

Podcast Interview on Freud:

"Dr Todd Dufresne on Freud's Looming Shadow of Deception," Skeptico (46 minutes on January 7, 2014). See at: https://skeptiko.com/235-todd-dufresne-freud-deception/

Key Books to Dig Into:

Borch-Jacobsen, Mikkel (1996). Remembering Anna O.: A Century of Mystification, New York: Routledge.

Crews, Frederick (1995). The Memory Wars: Freud's Legacy in Dispute, New York: New York Review.
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(editor 1998). Unauthorized Freud: Doubters Confront a Legend, New York: Viking.

Dufresne, Todd (2003). Killing Freud: Twentieth Century Culture and the Death of Psychoanalysis, London: Continuum.
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(2007). Against Freud: Critics Talk Back, Stanford: Stanford University Press.
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(2017). The Late Sigmund Freud: Or, The Last Word on Psychoanalysis, Society, and All the Riddles of Life, Cambridge: Cambridge University Press.

Gellner, Ernest (1993). The Psychoanalytic Movement: The Cunning of Unreason, second edition, London: Fontana Press.

Grosskurth, Phyllis (1991). The Secret Ring: Freud's Inner Circle and the Politics of Psychoanalysis, Reading, MA: Addison-Wesley.

Rieff, Philip [and Susan Sontag] (1959). Freud: The Mind of a Moralist, London: Gollancz.

Roazen, Paul (1969). Brother Animal: The Story of Freud and Tausk, New York: Knopf.

Roustang, Francois (1992). Dire Mastery: Discipleship From Freud to Lacan, Baltimore: Johns Hopkins University Press.

Sulloway, Frank (1979). Freud, Biologist of the Mind, Boston, MA: Harvard University Press.

Torrey, E. Fuller (1992). Freudian Fraud: The Malignant Effect of Freud's Theory on American Thought and Culture, New York: Harper.

Wortis, Joseph (1954). Fragments of an Analysis With Freud, New York: Simon and Schuster.

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History vs. Sigmund Freud - Todd Dufresne

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Working in Vienna at the turn of the 20th century, he began his career as a neurologist before pioneering the discipline of psychoanalysis, and his influence towers above that of all other psychologists in the public eye. But was Sigmund Freud right about human nature? And were his methods scientific?

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Why is cotton in everything? - Michael R. Stiff

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Centuries ago, the Inca developed ingenuous suits of armor that could protect warriors from even the fiercest physical attacks. These hardy structures were made not from iron or steel, but rather something unexpectedly soft: cotton. Today cotton is used to make everything from fabric, to currency, d…

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To learn more about Frederick Douglass's life, read this article on him. At the time, Frederick Douglass was one of the most powerful men in the Abolitionist Movement. Learn more about his power and influence in the Time for Kids article.To learn more about the Abolition Movement and its war on slavery, read this article on Slavery and Abolitionism.

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Frederick Douglass for kids (cartoon biography)

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Before there was a Civil Rights Movement, before there was a Civil War, there were people who stood against slavery. Frederick Douglass was one of the most prominent of those who spoke out against slavery. Watch this video biography of Frederick Douglass and learn about one of the Civil Rights Activists that existed before the protests began.

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Let's Begin...

How did America become the country it is? We started out as colonies. In this video by Flocabulary, you will learn about Colonial America and how these colonies set up the future success, failures, and conflicts when America won it's independence and became a country.

Create and share a new lesson based on this one.

About TED-Ed Best of Web

TED-Ed Best of Web are exceptional, user-created lessons that are carefully selected by volunteer teachers and TED-Ed staff.

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How did America become the country it is? We started out as colonies. In this video by Flocabulary, you will learn about Colonial America and how these colonies set up the future success, failures, and conflicts when America won it's independence and became a country.

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The myth of the Golden Fleece seems to begin as a classic hero's journey, with a love story that perseveres against the odds. But it ends tragically - with Jason's cold-blooded murder of the King's son and Medea's brother, Absyrtus.

Although there are different versions of Absyrtus' murder, the event makes is part of what makes the myth one of Ancient Greece's most transgressive - filled with complex characters and unclear motives. You can read the translation of Appolonius of Rhodes' source text here. The saga has also been represented visually in painting, sculpture and drawing - see here and here for some examples.

Perhaps the most controversial character in the saga is Medea, traditionally portrayed as a witch who forsakes her family for love and power. In the ancient playwright Euripedes Medea, which you can read here, the princess is a bloodthirsty tyrant. But later versions complicate and revise this demonization

The myth gets even more debatable with questions about what the golden fleece itself represents. Mythically, it was thought to be the hide of a magical flying ram named Chrysomallos who sported glittering golden curls. You can learn more about this creature here. Other interpretations focus on the fleece as standing for abstract concepts like power and corruption. In this epic tale of a man that can never be satisfied, we could also think about the fleece as symbolizing the gleaming allure of adventure - or the flickering line between Jason as a mighty hero, and someone willing to sacrifice everything for the sake of power.

And the tale doesn't end there. With the blood of Abyrstus on Jason and Medea's the Gods debate what to do with the disgraced crew. Hera, Jason's champion, insists that he has fulfilled his heroic duties by retrieving the fleece. But Zeus is furious at Jason's brutality, and sends storms to put the ship hurtling off course. In the later sections of the saga, Jason has to account for his wrongdoing while his complicit crew are doomed to wander restlessly with him.

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The myth of Jason, Medea, and the Golden Fleece - Iseult Gillespie

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In Colchis, the hide of a mystical flying ram hangs from the tallest oak, guarded by a dragon who never sleeps. The only way Jason can pry it from King Aeetes' clutches and win back his promised throne is by facing three perilous tasks- without the help of the Argonauts.

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Let's Begin...

What is it about the Mona Lisa that makes everyone stop, look and pose with her? Who was this young woman? Why are people so fascinated by this DaVinci portrait?

About TED-Ed Best of Web

TED-Ed Best of Web are exceptional, user-created lessons that are carefully selected by volunteer teachers and TED-Ed staff.

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What is it about the Mona Lisa that makes everyone stop, look and pose with her? Who was this young woman? Why are people so fascinated by this DaVinci portrait?

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Find population growth fascinating? Here's a great link to more data! Sift through it and find something of interest!Hans Rosling is the population guru! Watch his amazing TED Talk and learn Global population growth, box by box. The world population clock is very interesting. Click here to watch the population grow and then peruse the website to find more data on this topic!TED Ed has some great lessons on population! Watch:Overpopulation - the human explosion explained and Population pyramids: Powerful predictors of the future.

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Why do India and China have so many people?

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Find population growth fascinating? Here's a great link to more data! Sift through it and find something of interest!Hans Rosling is the population guru! Watch his amazing TED Talk and learn Global population growth, box by box. The world population clock is very interesting.

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The greatest mathematician that never lived - Pratik Aghor

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When Nicolas Bourbaki applied to the American Mathematical Society in the 1950s, he was already one of the most influential mathematicians of his time. He’d published articles in international journals and his textbooks were required reading. Yet his application was firmly rejected for one simple reason: Nicolas Bourbaki did not exist. How is that possible? Pratik Aghor digs into the mystery.

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Sojourner Truth was a key figure in American history whose story teaches us about the faith and resilience of enslaved people, the strength of their families, and the desire for freedom. Her experiences with slavery in the North illuminate one person's journey to freedom and shed light on activism in the aftermath of slavery.

Isabella Baumfree who named herself as Sojourner Truth as an adult, was the youngest child of 10 or 12 siblings. Her parents Elizabeth and James, worked hard to keep the family together in Ulster County, New York in an Afro-Dutch community. Through Truth's narrative, we learn that her family was not protected from the trade in human souls which took several of her siblings to the market. Such devastation and loss put the family, especially Elizabeth in a state of grief. Truth's parents did all they could to help the children remember their brothers and sisters who sold away from the family. Truth herself was sold five times (beginning at age 9), mostly as a result of changes in her enslavers' families, including death, marriage, and debt.

As the story notes, she named herself Sojourner Truth in 1843 and went on to become a great orator who enthralled audiences with her first-hand accounts of the horrors of slavery. Influenced by the Second Great Awakening, she embarked on a spirit-led public speaking tour. In the late fall of 1843 when Truth was about 46 years old, she gave a powerful biblical lesson from Daniel 3:30 at a tent meeting in Connecticut. She likened her experiences with those of "Shadrach, Meshach, and Abednego," who survived the fiery furnace. She explained that God walked with her through fires and protected her from being burned. She ended by dramatically asking her audience if they thought God's children could withstand fire. "It is absurd to think so!" she told them. While still in New York, she saw herself as allowing God to determine where she traveled and trusted God to provide the content of her remarks. Her work as an equal rights advocate and religious leader changed when she moved to Florence, MA. and joined the Northampton Association of Education and Industry, a social justice organization.

Her speeches and sermons moved people. They were humbled and inspired to see a black woman preach the word of God with an interpretation that differed from any they'd encountered before. Truth's words challenged their beliefs and caused people to think more deeply about their relationship with God. She spoke widely and passionately about spirituality. Crowds as large as 4,000 gathered to hear her, thus some venues created overflow spaces to accommodate her eager listeners.

Perhaps her most controversial speech, delivered in 1851 at the Ohio Women's Rights Convention, is how most remember her. Truth, nearly 6 feet tall, stood up and gave powerful remarks in "strong and truthful tones," according to Marcus Robinson who wrote about it in the Anti-Slavery Beagle. But scholars question the accuracy of this speech because of the way it was reported 12 years later by Frances Gale. Some accounts said Truth asked the audience "Ain't I a Woman?" when she was forced to stand behind a screen as a black woman attendee. Scholars debate the accuracy of these remarks and the conditions of this particular exchange. Regardless of the details, it is clear that she argued for equal rights for black women in spaces dominated by whites.

Several scholars have written about Truth and her impact on American history, including Nell Irvin Painter and Margaret Washington. Spending years researching Truth's life and legacy, Painter talked about her book on C-SPAN while Washington shared her biography at Cornell University. Truth will be remembered for her activism, resilience, and work as an advocate for black troops during the Civil War.

Truth continued traveling and speaking, funded by the proceeds of anti-slavery postcards that featured her image, until her death on November 26, 1883. She passed away in Battle Creek, MI where she lived with her daughters. Truth's life of activism, of strength and spirituality, and of questioning the meaning of the world around her lives on through the powerful words engraved on her simple tombstone which ask: "Is God Dead?"

Links:

Narrative; https://docsouth.unc.edu/neh/truth50/truth50.html

Trade in human souls-- http://www.inmotionaame.org/print.cfm;jsessionid=f8302246461587457241995?migration=3&bhcp=1

Second Great Awakening - http://nationalhumanitiescenter.org/tserve/nineteen/nkeyinfo/nevanrev.htm

Northampton Association of Education and Industry -
http://www.historic-northampton.org/highlights/educationindustry.html

Nell Painter on C-SPAN - https://www.c-span.org/video/?77043-1/sojourner-truth-life-symbol

Margaret Washington at Cornell - https://www.cornell.edu/video/sojourner-truths-america

Truth's Images by Daina Ramey Berry - https://www.biography.com/news/sojourner-truth-black-history

Sojourner Truth Library & Memorial in Massachusetts
https://sojournertruthmemorial.org

Equal Justice Institute on Sojourner Truth Day:
https://calendar.eji.org/racial-injustice/may/29

Sojourner Truth in Michigan
https://www.battlecreekvisitors.org/item/sojourner-truth-monument/

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The electrifying speeches of Sojourner Truth - Daina Ramey Berry

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Isabella Baumfree was born into slavery in late 18th century New York. Fleeing bondage with her youngest daughter, she renamed herself Sojourner Truth and embarked on a legendary speaking tour. She became known as an electrifying orator and her speeches impacted thousands of people in communities across the United States.