We took our first step into the strange world of magnetism when we played with magnetizing a nail. We learned that magnets do what they do because of the behavior of electrons. When a bunch of those crazy little guys get going in the same direction they create a magnetic field. So what’s a magnetic field, you ask? That’s what this experiment is all about.


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As the North and South sides of a magnet get closer together, the pull of the magnetic force is stronger. This is typical of fields. The closer you get, the stronger the pull of the force gets. The farther you get, the weaker the pull of the force gets.


Materials:


  • shallow dish or bathtub
  • water
  • foam blocks (or milk jug lids)
  • stack of 6-10 magnets
  • hot glue gun


Download Student Worksheet & Exercises


When you build the little boats, remember that you kept the poles all the same (all north pointed up, for example). The floating magnets repel each other because they have the same pole oriented up. But notice that when you bring the larger magnet close, they are all attracted to it and also make geometric patterns! When you bring the larger magnet in closer, the size of your pattern changes, doesn’t it? Most patterns have at least one (sometimes two) stable patterns, each of which is a local minimum energy pattern. The patterns that the little boats make are very similar to the crystal structures in solids.


Notice how the magnet boats repel each other when they get too close, yet the hold each other in a pattern. Atoms do the same thing – they repel each other when you try to squish them together, yet hold together to form molecules.


Exercises


  1. What shape do three magnets give? Why is this different from the shape that four magnets make?
  2. Why do the magnets flip over when you first place them in the water?
  3. How many magnets make a hexagon?
  4. How is this experiment like the compass experiments we’ve done so far?
  5. Why do the boats repel each other, yet still hold in a pattern?

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Comments

5 Responses to “Magnet Boats”

  1. If the magnets are not strong enough, then you won’t notice the repulsive forces between them. Take the magnets in your hands and see if you can feel the attraction/repulsion while you have one magnet in each hand. If you don’t feel anything, try another set.

  2. rachel_davis says:

    It doesn’t work very well, and I only have 3 big magnets.

  3. Sure, give it a try and let me know what happens!

  4. rachel_davis says:

    Can my magnets have plastic on the outside?

  5. Jennifer Reynolds says:

    How do atoms work?