Weather field note
Sky's stopwatch
Counting the Storm
You can guess how far away a storm is by counting the seconds between a flash of lightning and the rumble of thunder that follows.
Let's look closer
Why does thunder always come after lightning?
ight travels so fast, about 300,000 kilometers every second, that we see a flash of lightning almost the instant it happens, no matter how far away the storm is. Sound moves far slower, only about a third of a kilometer every second, so the boom of thunder takes noticeably longer to reach our ears. Counting the seconds between the flash and the rumble, then dividing by five, tells you roughly how many miles away the storm is; dividing by three instead gives you the distance in kilometers.
Look for this
Explorer clue
During a safe, distant storm, count slowly from the flash until you hear the rumble, then try again on the next flash to see if the storm is coming closer or moving away.
Your turn to wonder
Curiosity question
If you could measure distance with your own ears, what else might you want to listen for?
Keep wandering
