ELI5: Why does lightning happen?

Imagine you're rubbing a balloon on your hair. Sometimes, your hair sticks to the balloon, right? That's because of something called static electricity.

Lightning is like a giant, super-powered version of that!

Think about clouds like big sponges full of water droplets and ice crystals. These clouds bump into each other and rub together as they move around in the sky.

• This rubbing causes some of the water and ice to lose or gain tiny little bits called electrons.
• When a cloud loses electrons, it becomes positively charged (+).
• When a cloud gains electrons, it becomes negatively charged (-).

The ground also sends up a positive "feeler" called a streamer.

When the negative stepped leader from the cloud and the positive streamer from the ground meet, BAM! They create a complete path. All those negative electrons stored in the cloud suddenly rush down this path to the ground.

This massive rush of electricity is what we see as lightning! It's super hot and makes a loud noise, which we hear as thunder. Thunder is just the sound of the air rapidly heating up and expanding because of the lightning. So, lightning is just a giant spark of static electricity, like when you rub your socks on the carpet and then touch a doorknob!