Do you like to play with magnets? If you're like most kids, it can be a lot of fun to build things with magnetic toys. You probably also enjoy putting up your latest artwork or report card on the refrigerator with magnets. You may have even used magnets to learn about science in school.
But you might be surprised by how important magnets are in our daily lives. Just wait until you learn about how magnets are part of many of the things we use each day.
If you've ever played with a magnet, it was almost assuredly metal. In fact, it was probably mostly iron. Iron is the best magnetic metal on Earth. There are some other metals, including cobalt, nickel, and other rare-Earth metals, which are also magnetic.
Iron and other magnetic metals have physical structures that are made up of microscopic areas called magnetic domains. You could think of an iron bar as being made up of millions of smaller iron bars, all lined up in the same direction.
Each magnetic domain is like a tiny magnet in itself. When these are all lined up in the same direction, electrons at the atomic level move in the same direction to form magnetic fields that create the effects we know as magnetism. In other metals — ones we think of as non-magnetic — these domains are not lined up and simply point in random directions.
Sometimes a magnet can be rubbed across a non-magnetic metal to make it magnetic. When this happens, the magnet helps to align the magnetic domains in the non-magnetic metal in the same direction, thereby making it magnetic.
The force of magnetism is concentrated around the ends — called poles — of magnets. Each magnet has two poles: the north pole and the south pole. Although they might look the same, they behave differently.
For example, opposite poles attract each other. That pulling force of attraction you feel as magnets stick to each other is the north pole of one magnet drawing the south pole of another magnet toward it. Identical poles will repel (push away) each other. So when it comes to magnets, opposites really do attract!
Do you know of anything else that has a North Pole and a South Pole? If you said “Earth," you're right! Earth contains lots of magnetic metals that make the planet itself act like a humongous magnet. That's why you can use a compass to find which way is north: the magnetic needle on a compass is drawn toward the magnetic North Pole!
So are magnets just neat scientific toys? Certainly not! Magnets have thousands of practical uses. Some of them may surprise you. Did you realize that every electric appliance with an electric motor uses magnets to convert electricity into motion?
Magnets hold refrigerator and cabinet doors closed. They also read and write data on your computer's hard drive. If you listen to an MP3 player through headphones, those sounds you hear are thanks to tiny magnets that turn digital music into sound. Magnets are all around you every day, and they help make your life better in many ways you probably never imagined!