Breaking Magnets

Contributed by Sabrina Brickner

Introduction

• How do magnets work?
• What happens when you break a magnet in half? Do you get a magnetic monopole (a magnet which is only north or only south and not both)?

Materials

• A few magnets (bar shape is ideal)
• A thin piece of paper

Procedure

1. Take two magnets and put them together.
2. Flip one of the magnets around and try to put them together again. What happens?
3. Place one magnet down, then the piece of paper on top of it, then the other magnet on top of the paper (basically sandwiching the paper with the magnets). What happens now? Does the paper affect what the magnets were doing before? What does this tell us about how magnets work? (Compare to how glue and velcro work)
4. Take 2 magnets and stick them together. Now take another magnet and stick it to those. Now take another one and stick it to those again. What’s happening as we put these magnets together?

Physics Concepts and Questions

How do magnets work?

Magnets always have a North (N) pole and a South (S) pole. If we try to attach a N to a S they attract and stick together. However, if we try to attach a N to another N, or a S to another S, they repel.

How are the magnets still able to attract even when there’s a piece of paper between them?

At first glance, magnets appear to be sticky, kind of like glue, so we might think that they connect because of something on their surface. But this is not the case. As we see in our experiment, they are still able to attract even through a piece of paper. This tells us that magnets still work at a distance and that they don’t need to be in contact to still feel that magnetic push/pull. 

What happens when you break a magnet?

If we break a magnet into 2 pieces, each piece becomes its own magnet and still has a N and a S pole. We can see this ourselves in step 4 because when we put 2 magnets together, they act as one big magnet. And when we have 3 or 4 magnets together they still act just like a big magnet with a N and a S pole. Doing this in reverse, if we take our big magnet (made up of 4 magnets) and take one away, we are basically breaking our magnet into 2 pieces (the 3 magnet piece and the 1 magnet piece). And we can see that these pieces still act like normal magnets with a N and a S side each.

Conclusions and Further Investigations

• In step 3 what happens if you use a thick piece of cardboard instead of the paper? How far away can you put the magnets before they don’t appear to attract anymore? (They still attract, it’s just too weak compared to their weight to be noticeable!)
• If you add more magnets like we did in step 4, do you get a stronger magnet?