# data[].attributes.body
Biography

# data[].attributes.body
Biography (short version)

# data[].attributes.attachment_link.title
Nikola Tesla, Man Ahead of His Time (Biography part 1)

# data[].attributes.body
Biografia (versione lunga)

# data[].attributes.attachment_link.title
New Full Documentary - Serbian Scientist Nikola Tesla's Biography and Life 2017

# data[].attributes.body
A brief history

# data[].attributes.attachment_link.title
The vocabulary of electricity - James Sheils

# data[].attributes.body
Represent and explain in a timeline the most important discoveries regarding Electricity.

# data[].attributes.attachment_link.readable_text
What is static electricity? Why do we get a tiny spark when we've walked across a carpet and touched a doorknob? Or have you ever pet a cat and then picked up something metal, like a spoon to stir up cat food? Zap! (A tiny one.)

Find out what's going on in this TED Ed by Anuradha Bhagwat, with animation by Artrake Studio: The science of static electricity. Then dig deeper:

Human body tissue is composed of 60% or more of water. Human body is a good conductor of electricity! But dry human skin is a different story. Static electric charges can occur when you rub your feet or hand against an insulating material such as wool or plastic. It is important to remember that static charges, wherever they get accumulated, even on a human skin, lasts only for a short while. If these charges are not zapped off, then they leak off, as nature does not like charge imbalances. For all of us the best practice to avoid a static zap is to touch the Earth, or a wall, or a wooden door, before touching anything metallic.

Related reading via TED Ed: The TriboElectric Series, materials ranked by the order in which they lose or gain electrons, and at KidsHealth.org: How to Stay Safe in a Thunderstorm.

And for some static electricity experiments, try these.

# data[].attributes.attachment_link.description
What is static electricity? Why do we get a tiny spark when we've walked across a carpet and touched a doorknob? Or have you ever pet a cat and then

# data[].attributes.attachment_link.title
How Do Sharks and Rays Use Electricity to Find Hidden Prey? | Deep Look

# data[].attributes.body
Write a text about Edison and Tesla  and their contribution to the electrical theory (about 1 or 2 pages)

# data[].attributes.attachment_link.readable_text
Lightning is a powerful electrical discharge that occurs in mature thunderstorms. Lightning most commonly occurs within a cloud, either from a cloud to the surrounding air, or from a cloud to another cloud. Only about 20% of all lightning strikes occur between a cloud and the ground, which is what most people think of as classic lightning. Lightning strokes can heat the air through which they travel to an amazing 30,000 degrees Celsius (54,000F). This extreme heating causes the air to explosively expand, creating a shockwave that travels outwards through the air as the booming sound that we call "thunder." Lightning is still not fully understood aspect of thunderstorms, but much has been learned through observations with modern technology.

Lightning forms through the electrification of clouds, and the most popular theory is that this comes about through graupel and hail falling through the region of the cloud containing supercooled water droplets and ice crystals. As liquid droplets collide with hailstones and freeze on contact, the latent heat released keeps the surface of the hailstones warmer than the surfaces of the surrounding ice crystals. When the hailstones collide with the colder ice crystals, there is a net transfer of positive ions from the warmer hailstones to the colder ice crystals. The hailstones therefore acquire a negative charge, and the ice crystals become positively charged. The lighter ice crystals get carried upwards into the cold part of the thunderstorm by strong updrafts, causing the upper part of the cloud to become positively charged. The heavier hailstones fall toward the bottom of the cloud, causing the middle part of the cloud to become negatively charged. The lower part of the cloud is generally of negative and mixed charge, with some positive charged areas where precipitation is leaving the cloud.

Because opposite charges attract each other, the negatively charged bottom of the cloud causes positive charges to build in the ground directly beneath it. These positive charges will follow the cloud wherever it goes. The largest buildup of positive charges will occur in protruding objects such as houses, trees, and poles, which reach up toward the sky. The difference in charges causes an electric potential to build between the cloud and the ground, but in dry air, a flow current does not occur because air is a good electrical insulator. However, as the electrical potential gradient gradually builds, it will eventually become large enough (on the order of a million volts per meter) to overcome the insulating properties of the air, causing a current to flow, and lightning occurs. Cloud-to-ground lightning begins within a cloud when a sufficiently strong localized electric potential gradient causes a discharge of electrons to surge towards the cloud base and then towards the ground. This discharge proceeds in a series of steps, each about 50-100m long, with pauses of about 50 millionths of a second between each step. This is called a "stepped leader," and is usually quite faint, sometimes too faint to see with the naked eye.

As the tip of the stepped leader nears the ground, the electric potential gradient increases sharply, and a current of positive charge starts upward from the ground to meet it. Once they meet, a surge of electrons flows to the ground, and then a much more intense "return stroke" races upward towards the cloud along the same path traced by the stepped leader. This return stroke is what causes the bright flashes that we see as lightning,

and the transfer from ground to cloud is so fast that it is imperceptible to the human eye, and thus we see it as just a continuous flash of light. Lightning can occur only once, but more often there are multiple strokes that occur in the same channels that the air has already been ionized, and thus several strikes can occur in under a second. Sometimes these multiple strikes are perceptible to the eye, giving the appearance of flickering to the observer.Lightning animation depicting intercloud lightning in Toulouse, France. This sequence occurred during a duration of 0.32 seconds. Image courtesy:
Sebastien D'ARCO

Lightning striking east of Vail, Arizona in 1988. Photo courtesy: Jeff Smith

# data[].attributes.attachment_link.description
Lightning is a powerful electrical discharge that occurs in mature thunderstorms. Lightning most commonly occurs within a cloud, either from a cloud to the surrounding air, or from a cloud to another cloud. Only about 20% of all lightning strikes occur between a cloud and the ground, which is what most people think of as classic lightning.

# data[].attributes.body
Find out some other natural phenomena based on electricity

# data[].attributes.body
Start writing a vocabulary of unknown terms