Magnetism

If you are like me you have played with magnets. Maybe you pulled them off of the refrigerator at home. Anyway, you quickly saw that each magnet has two poles. If you want to see how magnets behave when you bring their poles together watch this video (click here)!

Things you can try on your own:

1. Get two magnets and see if you can get them to attract and repel each other.

2. The video showed what happens when two South poles are put near each other. Check what happens when two North poles are put together.

3. Magnets come in many shapes including flat, round, horseshoe shaped, and many others. Find magnets that have different shapes and find their poles. (Hint: you can find where the poles of a magnet are by bringing it near another magnet.)

4. See how close you can get two South poles. What does this tell you about the strength of the magnetic force? (If you donÕt know what the magnetic force is keep reading and answer this question later.)

What is a force? Is it just some weird science fiction idea?

No, a force is just a push or a pull. If you are feeling a push or a pull you are feeling a force!

The magnetic force is the pushing or pulling of magnets on each other.

What are magnets good for?

If you are asking yourself this question you should take a look around. Magnets are everywhere. They stick to your fridge and keep the door closed so the food stays fresh. In some stores they hold up signs. If you could see inside most machines you would find magnets. Your TV has magnets and so does your computer. Even the blender in your kitchen has magnets in it. Lets take a look at some used for magnets.

A compass needle has a magnet in it. One of the first uses of magnets was to find which way is North. You can do this at night if you can find the North Star but in the daytime you can not see the stars. The solution to this problem was the compass. In ancient times people discovered that certain rocks stuck to metal. They had discovered magnets.

Magnets were interesting. People started putting them in different places to see how they behave. They noticed that if you hang a magnet by a string away from any metal the magnet always points in the same direction. From that point on compasses were standard equipment for travelers. They are still used by hikers today.

You may be asking yourself how does a magnet know which way is North? The answer to that question may surprise you. The Earth acts like a giant magnet!

If you look at the picture above you might think I made a mistake. Why is the South pole of the magnet at the North pole of the Earth?

The answer is that for the North pole of a magnet to point North there has to be a South magnetic pole at the geographic North pole. People used to call the North end of a magnet the North seeking pole and the South, the South seeking pole. That made sense because the North seeking pole of the magnet points to geographic North.

Things to try:

1. Get a compass and walk around with it. See if the needle always points in the same direction.

2. Put the compass on a wood or plastic table. Bring a piece of metal near the compass. Move the metal around the compass. Does the metal affect the compass?

3. Put the compass on a wood or plastic table. Bring a magnet near the compass. Move the magnet around the compass. Does the magnet affect the compass?

4. Put the compass on a wood or plastic table. Bring a piece of plastic near the compass. Move the plastic around the compass. Does the plastic affect the compass?

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