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 What causes thunder and lightning?

Asked by: Madison Garey
School: Johnson City Intermediate School
Grade: 5
Teacher: Mrs. McCafferty
Hobbies/Interests: Basketball, reading, writing
Career Interest: Lawyer, orthodontist


Answer from Colin Evans

Resident Director; Colin has an MS in atmospheric science

Research area: Bio-diesel fuels, climate change, boundary layer weather modeling analysis Interests/hobbies: Baseball, reading, movies, writing

All weather is caused by the Sun. Without it we would have no weather, because the temperature differences between different areas of the Earth cause imbalances. For example, the equator of the Earth receives a lot more of the Sun’s energy than the North or South Poles do. The Earth wants to correct itself and settle down these imbalances. But the Sun is constantly shining, so the imbalances continue, and that is why we always have changing weather.

A thunderstorm is often created when a big area of warm and humid air is cooled rapidly and rises quickly, creating a cumulonimbus cloud. When a thunderstorm moves into the area, the high clouds of the storm, which are very cold, contain tiny bits of ice that are moving and swirling around really fast. Sometimes, the bits of ice will hit each other and cause little electrical charges, like when you rub your feet along a carpet and then touch something metal. After enough time goes by and this happens many times, the whole cloud will fill with electricity. There are two kinds of electrical charges; positive charges and negative charges. Positively charged electricity stays towards the top of the cloud and negative charges stay towards the bottom. And because opposites attract, the low clouds filled with negative charges cause the ground to fill up with positive charges.

There are three types of lightning: lighting that starts in a cloud and just stays within the cloud; lightning that starts in a cloud and reaches out into the sky; and lightning that starts in the cloud but connects all the way to the ground. When the positives charges and negative charges connect to each other, they create lightning. When this happens, the lightning actually splits apart the air that it goes through, forming a sort of channel for the electricity. When the lightning is gone, air goes back into the channel very quickly, and that is what causes the sound of thunder. A single bolt of lightning contains enough energy (nearly 5 billion joules) to power your house for two months. So remember to be safe; and when thunder roars, go indoors!

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Last Updated: 6/10/16