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Opposites Attract

In this investigation, students investigate polarity of magnets and explore what happens when two magnets are moved towards each other. 

Every magnet has a north and a south pole. Two like poles will repel each other but opposites attract. If we line them up so that norths face norths then they will push away hard enough to overcome the force we place on them (or the force of gravity!)

The force between magnets depends on the separation distance and the flux density (magnetic strength) of the magnets used.

Objectives

  • Explain which parts of a magnet are attractive.

  • Explain the difference between attraction and repulsion.

Materials

  • Per Demo or Group:
    2 horseshoe magnets or bar magnets, the bigger the better.

    Teacher Tip: ideal magnets for this demonstration are oversized horseshoe magnets, available at Boreal, but any strong, safe magnets will work.

Key Questions

  • Why can’t the magnets be pushed together when they are facing a certain direction?
  • Why do they attract when the two opposite poles are facing?

What To Do

  1. Hand two volunteers one magnet each, with the north poles facing each other.
  2. Ask students to predict what will happen when the two students bring the magnets close together. Try it!
  3. Have one student flip over the magnet and then try it again.

Extensions

  • Donut or disc shaped magnets have north on one face and south on the other. Try threading them on a pencil or dowel to make them repel each other in defiance of gravity.
  • Make a pencil levitate using this set up!

Other Resources

Toys From Trash | Levitating Pencil