By Christos Papageorgiou
Hey, it is raining! Look outside of your window. Wow! Did you see that flash? Are there any paparazzi taking pictures outside of your house? No! This is a lightning!
Lightning is electricity and involves particles with negative and positive charges. So, what is it actually happening? How can lightning be created? The secret lies inside the big heavy dark clouds you see up the sky. The clouds are formed from tiny water droplets. During a storm, the air moves around and makes these water droplets crash into each other and separate. Usually, the big water droplets in a cloud are negatively charged and the small ones are positively charged. The big water droplets which are are heavier, so sit in the bottom of the cloud and fall to the ground as rain. The movement of the negative charges from the cloud to the ground is called a stepped leader. At the same time, positive charges from the surface of the earth start to go upwards (this movement is called an upward leader) and when the stepped and the upward leader meet, they create a flash of electricity called lightning.
Picture adapted from: http://www.virginiaplaces.org/climate/lightning.html
Safety tip: Lighting is very dangerous! As you can see from the pictures below, lightning strikes tall objects, like very tall skyscrapers. Thanks to the engineers, it is totally safe to be inside a skyscraper when a lightning strikes. But when you are outside, please do not hide under trees, because it's very likely to be struck by lightning.
Picture adapted by: https://www.youtube.com/watch?v=Cz_uYBx1G5s
Thunder is the sound of the lightning! When a lightning strikes, the air is heated up quickly. The intense heating causes the hot air to quickly expand into cooler air around it. This creates a shockwave, that’s why we hear a thunder.
Picture adapted by: https://www.youtube.com/watch?v=cu6K5h-J6xQ
Did you know that when lightning strikes, you can first see the lightning before you hear the thunder? Do you know why?
That is happening because the speed of light is much faster than the speed of sound. Light travels at 670,600,000 miles per hour, but sound travels at a measly 727 miles per hour.
Fun Fact 1: White strikes (lightning) flashes between the cloud and the ground. Lightning can happen between the clouds or in the cloud too.
Fun Fact 2: A bolt of lightning strikes somewhere on the Earth every second. Here is a live map of lightning strikes around a world:
Fun Fact 3: The average temperature of lightning is around 20000 °C (36000 °F)
Fun Fact 4: Astraphobia is the fear of thunder and lightning.
Fun Fact 5: Lightning can strike without rain in some dry places.