Lightning
is caused by electricity. We can’t see electricity, but we can use these
magnets to learn about it. Magnets has positive and negative side. When we put
two magnets next to each other, it comes together. That’s because the positive
side of one magnet attracts the negative side of the other. Opposites attract.
When we use the other end, the two magnets push apart. That is because the
sides of the magnets with the same sign do not attract. Now that you know
little about positive and negative, let’s see what they have to do with
electricity. Look at the cloud. A cloud is made up of many, many drops of
water. When the drops get big and heavy, they fall toward the earth as rain.
Some of the drops have a positive charge of electricity. Some of them have a
negative charge. Let’s look inside the cloud. When a group of drops with a
positive charge comes near a group with a negative charge, a large electrical
spark is cause. Then we see a flash of lightning jump between the two groups of
drops. It is just like the magnets-opposites attract. This same thing can
happen between two different clouds that come near each other. If a group of
drops in one cloud has a positive charge and a group in the other cloud has a
negative charge, lightning can jump between the clouds! Sometimes lightning
jumps from a storm cloud to the ground. The earth and a group of drops in the
cloud attract each other because they have opposite charges. Lightning is
powerful and, at times, very dangerous.
Thunder is
just a lot of noise. It’s nothing to be afraid of. Air is made up of tiny parts
called molecules. When lightning flashes, it gives off a lot of heat. This heat
makes the molecules start to move and bounce. Soon the heated molecules bump
into molecules of cold air and make a big air wave. This wave is the sound of
thunder we hear after we see a flash of lightning! So thunder is just a lot of
harmless noise.
Review:
The drops
of water in a cloud can have a positive or a negative charge. When two opposite
charges come near each other, a large spark of electricity happens and we see a
flash of lightning! As the lightning heats the air, the molecules bounce
together and make a great air wave-the sound of thunder! And it’s harmless!