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Video, questions and discussion about how we hear sounds. So many extension activities can also be done with this video. Students can sequence the process of hearing sounds (either on paper or as a class). Students can learn about the relationship between frequency (Hz) and pitch and loudness (dB). Students can also create different musical instruments to reinforce these concepts.

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The auditory system is a sensory system that involves both the peripheral and central nervous system. To learn more about the auditory system requires understanding the principles of neuroscience. Check out these introductions to the nervous system and the auditory system. A more complete introduction will come from a university-level physiology or neuroscience textbook, such as this one.

All of the components of the auditory system work together to allow us to hear. The central auditory system consists of the cochlear nucleus, the superior olivary complex, the lateral lemniscus, the inferior colliculus, the medial geniculate body, and the auditory cortex. The Encyclopedia of Neuroscience Online includes articles about most components of the auditory system. In-depth information on the auditory system for the budding scientist is presented in the Springer Handbook of Auditory Research, a series of 65 books on all aspects of the auditory system, hearing, and hearing loss. These books continue to be published with new volumes coming out every year.

There are many interesting phenomena in the auditory system to explore. In the outer ear, sound is funneled by the pinna into the external auditory meatus, where it reaches the eardrum. So how does the size and shape of your ear affect what you hear? The ossicles in the middle ear sometimes freeze and are unable to conduct the vibrations from the eardrum to the cochlea. How is this hearing loss different from damage to the cochlea? The cochlea of the inner ear is complex and is the site of sensory transduction, where the mechanical signal is converted into a neural signal-but what are the molecules and channels involved in this process?

There are two types of hair cells. Inner hair cells connect to 95% of the fibers in the auditory nerve. How do inner hair cells transmit neural signals to the brain? Why are the synapses of the inner hair cells on the dendrites of the spiral ganglion cells among the fastest synapses in the nervous system? There are three times more outer hair cells than inner hair cells. Why do outer hair cells move up and down like little muscles during sound stimulation?

The auditory vestibular nerve, otherwise known as the eighth cranial nerve, sends signals from the hair cells to the cochlear nucleus in the brain. However, at the cochlear nucleus, many neural circuits begin to carry different types of information. Sound localization requires binaural sound stimulation with two ears. How does information from the two ears get combined and compared in the superior olivary complex so that we can localize sound? Why are the largest synapses in the brain found in the cochlear nucleus and superior olivary complex? Are there brain circuits that tell us what a sound is instead of where a sound source is located?

The inferior colliculus receives information from almost every part of the auditory brainstem, including the cochlear nucleus and superior olivary complex. This answers certain aspects of the what and some of the where, so how does it integrate all this information? There are multiple core auditory cortical areas surround by a belt of other auditory cortical areas. How is the information related to what and where distributed amongst the areas of auditory cortex?

When we have a hearing loss, it impairs our ability to communicate with others even when we are not deaf. However, some hearing loss is gradual and not noticed at first. This may be especially true for noise-induced hearing loss if we have chronic exposure to moderately loud sound, as opposed to extremely loud sound. Find out more about noise-induced hearing loss here.

Many people have a ringing in their ears called tinnitus, which never stops-even when there is no sound. This is a symptom rather than a disease. There may be many causes of tinnitus; exposure to loud sound may be among the most common causes. However, we are still not clear about what happens in the auditory system and how to cure the problem. Find out more about tinnitus here.

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The science of hearing - Douglas L. Oliver

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The ability to recognize sounds and identify their location is possible thanks to the auditory system. That's comprised of two main parts: the ear, and the brain. The ear's task is to convert sound energy into neural signals; the brain's is to receive and process the information those signals contain.

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Check out ASLdeafined.com, a fantastic resource specifically designed for young learners. It includes kid-friendly vocabulary, games, and interactive lessons to make learning ASL fun and engaging.

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Want to learn how to do ASL? ASLdeafined provides how-to video courses taught by Deaf experts. Visit us to begin learning the ASL language today!

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There are many great apps that make learning ASL interactive and enjoyable. The ASL App and ASL Kids are two popular choices that offer age-appropriate lessons and games for elementary students.

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Written by Lynne Kelly; published in 2019

Winner of the Schneider Family Book Award

Book Review:

This is the story of twelve year old Iris, a tech-wizard and the only deaf girls in her school, and her quest to help a whale, Blue 55. Often isolated and misunderstood, Iris uses her knowledge of technology to connect and communicate with Blue 55. She researches and formulates a plan to communicate with Blue 55. The only obstacle-figuring out how to get to Alaska to bring her plan to fruition.

Rationale/Activities:

Instructional Goals:

Knowledge building

Reading Comprehension strategy instruction

Critical literacy

Engaging students in reading

While the story is written as engaging fiction, there is a significant amount of factual information related to technology, communication, hearing, scientific research and whale behavior.

Blue 55 is a fictional whale based off of Blue 52-a whale that communicates at a frequency outside of normal whale-song frequency.

https://www.youtube.com/watch?app=desktop&v=L7mTZAhCeyA&t=0s&t=529

Literary analysis-character analysis, symbolism and foreshadowing

Scientific research on whales-keep a science journal

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Video that explains how whales hear sounds.

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Although whales are mammals that breathe air, they spend most of their time roaming the depths of the oceans. There, sound travels faster underwater and farther than it does on the world's surface, at about 1500 meters per second compared to just 340 meters per second in air. So, a whale's world is replete with sound - it's a key element to its survival, touching everything from socializing and breeding to navigation and feeding.

But if whales don't have any sign of external ears, how do whales hear sounds? Scientists use anatomical data, mathematical models, and behavioral experimental data to test echolocation and other hearing methods out in the wild.

Do Whales Hear Sound?

All whales rely heavily on sound to understand information about the world around them. Researchers at the Smithsonian Museum created detailed 3-D images of 56 whale fetuses from 15 different species of baleen and toothed whales from the museum's specimen collection and compared and contrasted them with fossilized ears of extinct whales from millions of years back.

What Are Toothed Whales?

Toothed whales are the category of whales including beaked whales, sperm whales, and even dolphins. They're called toothed whales because they literally have teeth. These marine mammals are specialized in high-frequency sounds, or 'ultrasonic' sounds.

How Does Echolocation Work for Whales?

Toothed whales are famous for their ability to produce high-pitched clicks and bounce sound off of elements in their environment to understand where they are and what they're like. They use this biological sonar technique, called echolocation, to get around, find food, and 'see' their surroundings. This is an ancient ability that is thought to have developed independently several times throughout evolution.

They can hear sounds we cannot even remotely perceive, such as frequencies exceeding 150 kilohertz in some species.

What Are Baleen Whales?

Humpback whales, blue whales, and right whales are categorized as baleen whales because they feed by filtering plankton through a fringe-like structure in their mouth called the baleen. They are some of the largest creatures on Earth.

What Are Whale Songs?

The sounds Baleen whales make tend to be low-frequency - known to science as 'infrasonic' - and can travel long distances. These far-reaching, low-frequency sounds are often woven together into eerie, melancholic songs that whales use to communicate with each other.

"But past those two points, we don't know, probably a bit lower, probably a bit higher, that's all we know, at this point," says Dunlop. Her work also is starting to suggest that humpback whales are most sensitive to sound at approximately 4 kilohertz she says - actually where humans are quite sensitive as well.

Do Whales Have Ears?

Humans have a fleshy outer structure to the ear that captures sounds and directs them into the internal bones of the ear, which is tasked with deciphering them for the brain to understand. This is the same for most land mammals: cats, dogs, monkeys, horses, cows, and hippos. This fleshy part is called a "pinna." In water though, it doesn't work as well.

These fatty pads are detailed convolutions that are specifically designed to entrap the frequencies they need to, just like the cartilage around our ears. Then, sound travels into the bony labyrinth of the ear and to the cochlea.

How Do Whales Hear?

Much of how baleen whales hear, compared to toothed whales, is still a mystery. This is mainly because it's difficult to study baleen whales: they're just too big. A baleen whale's ear is as big as a human head and as dense as a bowling ball, according to Ketten.

Baleen whales have fat pads close to the ears too, and their ear bones are homed inside a conch-like bone the size of a bulldog's head bulging on the side of their skull.

If the sounds are longer than the whale's body, the whale uses their skull to capture the sound and conduct it, amplifying it as it vibrates through their skull, before making it to the tympano-periotic complex. This is almost four times more sensitive than just letting sound pressure reverberate through tissue, so this is likely the mechanism that baleen whales use the most.

Ketten doesn't agree with this theory, though. Using the skull to conduct sound to the inner ear wouldn't let the gigantic whales hear where the sound is coming from, argues Ketten - something these animals seem to be quite good at.

How Humans Interfere With Whale Communication

The issue with whales being so sensitive to underwater sound and having such sophisticated methods to make sense of it, likely means they're also highly affected by all the raucous we input into the ocean: ships, sonars, and military tests all add noise pollution to the world's water basins. This is, again, difficult to test though, according to Dunlop, because of how different all of these sounds can be.

Dunlop's team has already found that air guns used in marine exploration by military teams are loud enough to be heard by hum pback whales as far as three kilometers out - it's still unclear whether this impedes them from communicating with each other, though, because air guns go off at intervals. It's likely that constant vessel noises, on the other hand, will mask their communication signals, says Dunlop, preventing humpback whales from communicating not within a group, but probably between groups.

More research is needed to figure out whether these human-made sounds could affect their migrating patterns, their ability to communicate, feed, and breed, and how this data can inform mitigation strategies for noise in the ocean.

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How do Whales Hear Their Songs and Other Sounds if They Don't Have Ears?

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How do whales hear sound? Echolocation and other underwater adaptations help them, but humans may be interrupting their whale songs.

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Written by Dr. Stephanie Nishek (mother of a deaf child) and Illustrated by Priscila Soares (an artist who uses a BAHA); published in 2019.

Book Review:

This book is an excellent introduction to the diversity of the Deaf community. Children who are deaf, hard-of-hearing and deaf-blind are represented in this book along with types of devices a person may use: hearing aids, bone anchored hearing aids and cochlear implants. A variety of communication styles are also introduced.

Rationale/Lesson Ideas:

This book contains a lot of factual information in a clear and efficient way. "All the Ways I Hear You" may be used to introduce vocabulary related to the diverse members of the Deaf community, show representation of a student with hearing loss in your classroom or encourage students to consider people and experiences different from their own.

Instructional Goals:

Knowledge building

Visual literacy skill development

Critical literacy

Possible lesson ideas:

Prior to reading, ask students if they know anyone with hearing loss, have seen anyone with devices to assist communication or seen anyone use sign language. Show the read aloud that includes ASL https://www.youtube.com/watch?v=YIEaFnkB02M Students can identify new vocabulary words and have a discussion to explore types of hearing loss and communication modes.

Group work to do a deeper dive into types of hearing loss, communication options or types of assistive technology could also be done.

Present "what if" scenarios to students to see how students might adapt communication to meet the needs of other. This could be done in journal form to include more writing skill development.

Discuss the importance of representation. Who should be telling the stories or providing information about members of specific communities?

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There are many helpful tools online to teach basic ASL, but consider inviting a member of the Deaf community or an ASL teacher to visit your classroom!

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people having a conversation using American sign language

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Written by Shannon Stocker and Illustrated by Devon Holzworth Published in April, 2022, winner of the Schneider Family Book Award for Best Picture Book in 2023

Book Review:

This beautifully illustrated book tells the true story of Evelyn Glennie, the first deaf woman to become a full-time percussionist in the world.

Instructional Goals:

Knowledge building

Critical literacy

Engaging students in reading

Possible Lesson Ideas:

Learn about the different pitches that drums or percussion instruments can make

Story mapping

vocabulary study: from words such as audiologist, onomatopoeia, disparaging, and percussionist, this book is full of tier 2 and 3 words

Character study of Evelyn Glennie

Make connections to Song for a Whale and All the Ways I Hear You

Watch Evelyn Glennie videos on YouTube