Year 3 Science

science owl

That Special Magnetic Attraction

magnet experiment

We started learning about magnetism in Year 1, and we learn much more in Year 3. In the activity An Invisible Force, you experimented to see what sorts of things a magnet attracts. Will it attract everything? For example, will it pull a shoelace or tissue or plastic comb toward it? No. Those things are not made of iron. But a paper clip is made of steel, a metal that has iron in it. Magnets attract things made of iron. But magnets do not attract copper or aluminium. Bring a magnet close to some aluminium foil and you'll see. Will the magnet attract pennies? Pennies and 2p coins were made of copper until 1992. New coins are mostly steel with a thin copper coating. Which coins will the magnet attract? Try it out!

Here's an experiment you can do with two bar magnets. Put the two bar magnets on a table. Bring an end of one of the magnets toward an end of the other. What happens? Do they pull together or push apart? Now turn just one of the magnets around, and bring the ends together. What happens now? If your magnets pulled together the first time, then this time they will push apart. If your magnets pushed apart the first time, then this time they will pull together.

Why? In What Your Year 3 Child Needs to Know, we look at a bar magnet and its magnetic field. Even though you can't see the forces coming from that magnet, a picture in the book shows them with little lines. The lines show what's called the magnetic field, which is present in the space around the magnet and where the magnetic force can be felt. If you put a paper clip inside the magnetic field, the magnet will attract the clip.

The magnetic force is strongest at the two ends of the bar magnet. We call those two ends where the magnetic force is strongest the magnetic poles. Even though the poles of a magnet may look the same, they are different. We need names for these two poles so we can tell them apart. We call one pole 'north' and the other 'south'. Why are the poles called north and south? For the answer, try this. Take a bar magnet and tie a string around its middle so it balances when you hold it by the string. Tape the other end of the string to something, such as a table, so that the magnet can hang and move freely. Watch what it does when you let it go. The bar magnet will turn around until it settles in one direction. Notice something in the room that one pole (one end of the magnet) is pointing to, for example, a nearby lamp or picture. Put a little sticker on the end pointing to the lamp or whatever you've chosen. Then gently twirl the magnet. When it stops again, what happens? The pole with the sticker is pointing in exactly the same direction, isn't it?

If you kept doing this experiment with every bar magnet you could find, every one of them would point to the same direction. That's because your magnets are finding the forces of magnetic attraction that exist in nature. They are being pulled by great fields of magnetic attraction that surround the earth.

That's right, the earth is like a great big magnet! The magnetic fields surrounding the earth are strongest very near the North Pole and the South Pole. So, one end of your magnet is pointing north and the other is pointing south. And that's why the poles of your magnet are called north and south.

This activity is adapted from pages 308 - 310 of What Your Year 3 Child Needs to Know, which can be purchased here. Click below to see related activities.

science owl