# Magnetism

This month's topics are magnets and magnetic fields. Kids will bounce magnets to help them understand where magnetism comes from and how magnetic fields interact with each other.

## Key Concepts

 The magnetic field comes from a north pole and goes to a south pole. Opposite poles will attract one another. Like poles will repel one another. Iron and a few other types of atoms will turn to align themselves with the magnetic field. The Earth has a huge magnetic field. The magnetic field probably comes from the moving electrons in the currents of the Earth's molten core.

The Earth has a north and a south magnetic pole which is different from the geographic north and south pole. Compasses turn with the force of the magnetic field.

## Experiment & Video

Did you know that you can transfer energy through a magnetic field? It's simple to do! We're going to have a look at magnetic fields in this simple experiment.

Materials:

• three magnets, all the same size
• optional: aluminum (not steel) cookie sheet

## What's Going On?

What causes magnetism? Believe it or not, electrons! Those wacky little fellows that we learned about last time are the key to magnetism. More accurately, a majority of electrons moving in a similar direction creates a magnetic field.

Electrons move on their own. They move around the nucleus and they spin. It's the electron spin that tends to be responsible for the magnetic field in those "permanent" magnets.

Electrons can have a "left" or "right" spin. If an atom has more electrons spinning in one direction than in the other, that atom has a magnetic field. If an object is filled with atoms that have an abundance of electrons spinning in the same direction, and if those atoms are lined up in the same direction, that object will have a magnetic force.

 The reason some things are magnetic and other things aren't is due to the balance of the spinning electrons. Most atoms have a fairly even number of left and right spinning atoms. If there's four spinning left, there's four spinning right. If there's nine spinning right, there's eight spinning left. Since they are fairly balanced, there's no net direction that the electrons are moving in. With no over all direction of movement there's no magnetic force.

However, there are a few atoms, iron being the most famous, that are not in balance. Iron has four more electrons that spin in one direction than in the other. This excess of same spinning electrons creates a net directional movement and thus, a magnetic force! Nickel and Cobalt are other fairly common magnetic metals.

1. What happens when you break a magnet in half? Can you separate the poles?

2. Why does your refrigerator magnet stick to the fridge door?

3. Does your magnet stick to aluminum (like a soda can)?

4. Name the biggest magnet you can think of.

5. Where is the magnetic south pole?

6. What happens when you try to stack the magnets north-to-north?

7. How many magnets can you get to bounce and interact with each other?

8. Does the shape of the magnets matter? Size? Strength?

9. What if you stick two magnets together and try this experiment again?

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