What is Thunder?

Thunder is the sound that lightning makes. Sounds simple but why does lightning make a sound?

Any sound you hear is made up of vibrations, the vibrations travel through the air as waves until they reach your ear. This means lightning must cause some vibrations. Lightning is a huge discharge of electricity. When lightning strikes, huge amounts of electricity shoots through the air, and this causes two things to happen:

1. The electricity passes through the air and starts it vibrating. The vibrations cause sound.

2. The lightning is also very hot and heats up the air around it. Hot air expands and the air gets bigger very quickly, and pushes apart the air particles.

These vibrations are what you hear and call thunder – the rumbling of thunder is caused by the vibration or sound bouncing of the ground and the clouds.

Why is thunder not at the same time as the lightning?

We see the lightning before we hear the thunder because light travels faster than sound. The light from the lightning travels to our eyes much quicker than the sound from the lightning so we hear it later than we see it.

Why don’t you?

Try out a light and sound experiment yourself.

Get another person to stand along way away from you but so you can still see them.

Clap your hands get the person to raise their left hand when they see you clap and their right when they hear you clap.

There should be a gap similar to lightning and thunder except that lightning is even further away so the gap is even bigger.