The Bedtime Scientist

A question

Why does thunder come after lightning?

A calm, true answer. Then, if the wondering keeps going, the whole episode.

The short answer

They happen at the same instant. Lightning heats the air around it hotter than the surface of the sun, that air shoves outward all at once, and the shove is the thunder.

Light simply travels much faster than sound, so the flash arrives almost immediately while the rumble is still on its way. Count the seconds between them and divide by five, and you have roughly how many miles off the storm is.

Which turns a frightening noise into arithmetic.

Go deeper tonight

Thunder & Lightning: The Sky's Electric Lullaby

The full episode, in one calm voice, with nothing that startles.

The episode

Thunder & Lightning: The Sky's Electric Lullaby

0:00 12:55
Sleep timer

Read the guide for this one in the morning.

This connects to

Sound and echoes

One idea turns up in many different nights. Follow one and the library starts to join up.