Flash and bang
Oh, oh—you’re caught in a rainstorm! The sky is dark and angry and
rain is spattering down all around you. Suddenly, a zigzag flash of
lightning brightens the sky for just an instant. Almost at once, there’s
a tremendous ripping sound and then a crash of thunder!
What causes these bright flashes and loud crashes that make a rainstorm
so scary and exciting?
Lightning is caused by electricity. Each tiny drop of water in a rain
cloud has a tiny charge of electricity. There are billions of water
drops in a cloud, so the whole cloud has a powerful charge of
electricity. Sometimes the charge inside the cloud is so powerful that
electricity flashes from one part of the cloud to another. And
sometimes, when the cloud comes near another cloud with an electric
charge, or near the ground, electricity rushes between them. So, the
flash we see when lightning snakes through the sky is really a huge
electric spark.
A flash of lightning heats up the air around it. The heated air goes
rushing out in all directions. It slams into the cold air, making it
shake. This is what causes the crash of thunder.
It’s a Fact
You can tell how far away lightning is. Count the seconds between the
flash and the thunder. Every five seconds equals one mile (1.6
kilometers).
