KIAN GLASS

Lightning | Electricity | Physics | FuseSchool

A flash of lightning, and a rumble of thunder. But what exactly are these spectacular occurrences?

In 1752, Benjamin Franklin discovered that lightning was caused by powerful electrical discharges in clouds. He wasn’t the first person to discover electricity or the first to think that lightning was made of it.

But he did prove it to be the case, by flying a kite during a thunderstorm. Luckily his kite wasn’t actually struck by lightning, because it would have fried him in his boots!

Thunderstorms are caused by small electrically-charged particles.

As water molecules in the cloud are heated and cooled and they move up and down against each other, there is a separation of charge. Forming 2 poles within the cloud. One part becomes negatively charged, and the other part becomes positively charged.

Objects on the ground then become oppositely charged to the lower part of the cloud.

This imbalance tries to resolve itself, by passing current between the differently charged poles.

Charged particles always flow in the direction where there are less particles of the same charge. This results in a lightning bolt.

Sometimes the bolt will carry a positive charge, and sometimes a negative charge.

At first, there is a bolt which is invisible to our eyes.

When the invisible lightning bolt gets close enough to the ground, there is a powerful discharge of energy. So powerful, in fact, that it results in an electrical arc. This is the lightning bolt that we see.

The electrical arc of the lightning bolt heats the surrounding air to extreme temperatures. In fact, the air around it can be heated to 5 times hotter than the sun!

This heat causes the surrounding air to rapidly expand and vibrate. Which is the rumbling thunder that we hear.

Lightning comes in many different colours

The colour depends on atmospheric humidity, temperature and levels of air pollution.

Lightning also transports massive amounts of energy. 5 times hotter than the sun, so that makes sense.

Each bolt carries about 10 billion Watts. That’s enough power for 32 million people a year!

10 billion watts per bolt, and given that 50 bolts strike the earth’s surface every single second means the power of lightning is extraordinary. And dangerous - over 2000 people a year are killed by lightning.

Extracting electricity from lightning sounds like a good idea, right?

Well in reality,

• predicting where the lightning is going to hit to have our equipment is nearly impossible,

• we’d need to develop the technology that can conduct and store this amount of instantaneous power.

• The equipment has been predicted to cost over 90 trillion US dollars… this is all the money in the world!!

• We don’t know if the lightning bolt is going to be positively or negatively charged… and so our equipment would need to cover both possibilities

Despite this, scientists are still trying to harness lightning’s electricity. You might as well try!

CREDITS

Animation & Design: Reshenda Wakefield

Narration: Lucy Billings

Script: Bethan Parry

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