April 29, 2013

What is Lightning?

Hi, I’m Emerald Robinson, and in this “What is Video,” we’re going to talk about the electric force of nature known as lightning.

Lightning is the flash of light produced by the natural discharge of a large amount of static electricity. This discharge is sometimes called a “strike.”

Lightning is very common according to fulminologists, the scientists who study it. Lightning strikes somewhere in the world between 40 and 50 times a second. Yet, as common as lightning is, scientists aren’t entirely sure what causes it.

We do know that, during some storms, clouds develop areas of positive charge and negative charge due to the movement of ice and water droplets within them. Negatively charged areas form at the bottoms of clouds, and positively charged ones form at the top. As the strength of the negative charge at the bottom of the cloud increases, it begins to repel negatively charged particles on the ground’s surface, causing the ground to accumulate a net positive charge. When the difference between the cloud and the ground overcomes the insulating effect of the air between them, the charge coalesces into a bolt of lightning that strikes the ground.

This is called cloud to ground lightning. Cloud to cloud lightning occurs when the strike is between two different clouds; if it’s within oppositely charged areas of the same cloud, it’s called intra-cloud lightning.

Because electricity moves over the path of least resistance, lightning tends to strike tall objects. For safety, we sometimes equip buildings with lightning rods, which safely conduct lightning’s electricity down into the earth through a wire.

Contrary to popular belief, lightning does strike twice – sometimes much more often! At up to 54,000 degrees Fahrenheit, lightning is six times hotter than the sun, so seek shelter in a storm to avoid being struck by this powerful natural phenomenon.

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