Book 1, Question 55
Why Does Thunder Follow Lightning? Light Wins the Race!
Flash first, boom later! A lightning bolt is super hot and heats the air around it to hotter than the surface of the Sun. That air expands fast and explodes outward in a shock wave, which we hear as thunder. Light travels much faster than sound, so you see the flash before you hear the boom. The page shares a tip: count the seconds between them and divide by 3 to estimate the distance in kilometers.
From the book
Page from A Million Whys Book 1
More fun facts
- Lightning starts as static charges in a rain cloud.
- Lightning often happens between clouds or inside one cloud, not just from clouds to the ground.
- Lightning can be as hot as 54,000 degrees Fahrenheit, which is five times hotter than the surface of the Sun.
- Lightning heats the air around it in a fraction of a second, and that blast makes a shock wave we hear as thunder.
- A shock wave forms at every point along the lightning bolt. Millions of them together make thunder's long rumble.
- Thunder can usually be heard up to about 10 miles away.
- Several strokes can travel down the same path, which makes a lightning bolt look like it flickers.
Questions kids ask
Why does thunder rumble instead of just booming once?
Shock waves form all along the lightning bolt, and millions of them reach you at slightly different times.
How far away can you hear thunder?
Usually up to about 10 miles.