Thunder

weather · lightning · sound · physics

Sound from lightning. Thunder is created when a lightning bolt heats the air around it so incredibly fast that the air expands and creates a sonic shock wave, kind of like nature's explosion.

Distance changes sound. If lightning is close by, you hear a sudden loud crack, but if it is far away, you hear a long, low rumble instead because sound travels slowly through the air.

Count the seconds. You can estimate how far away lightning is by counting the seconds between the flash and the sound, then dividing by five, since sound travels about one mile every five seconds.

Temperature creates pressure. Lightning is so hot that it instantly pushes the air around it, and that rapid expansion of hot air is what makes the booming sound you hear.

Thunder has a science name. Scientists who study thunder call it brontology, and people who are afraid of thunder have a phobia called brontophobia.