Thunder and Lightning

With the start of spring typically comes thunderstorms. It might be fun to keep track of the first thunder and lightning of the year. What day do you first hear thunder? What was the weather like the day before, warmer or colder? What is the weather like after the thunderstorm, warmer or colder?

It is possible to use thunder and lightning to measure how far away a storm is. Here's how:

Lightning travels at the speed of light, about 186,000 miles per second. This means that you see lightning pretty much when it happens. When lightning strikes, a noise is made which we call thunder. Thunder travels much slower, at the speed of sound, about 1088 feet per second. It takes sound about 5 seconds to travel one mile. You can observe this for yourself.

Go outside and watch as a jet flies overhead. Where do you see the plane? Where do you hear the plane? If the jet is flying high, there will be a distance between where the plane can be seen and where it can be heard. You can see where the plane is right now. You hear where it was a little while ago. This is caused by the slower speed of sound.

So, if you time how long it takes to hear thunder after you see lightning, you can find out how far away the lightning struck. Use a watch or clock with a second hand or count the seconds. If you say "one thousand one, one thousand two, one thousand three", you have counted about 3 seconds. You can practice this with a clock to get the timing right if you want. Every 5 seconds between when you see lightning and when you hear the thunder is one mile. If you count 10 seconds between the lightning and thunder, the lightning struck 2 miles away.

For further information about lightning and safety, visit the website of the National Lightning Safety Institute. For other information from the National Weather Service about thunderstorms, click here. Sabrina was struck by lightning and was lucky not to get badly hurt. You might be interested in her Webpages on lightning.
View text-based website