How to Make a Compass With Styrofoam

In the 13th century, a crusader named Peter Peregrinus devised a basic compass by floating a circularly shaped lodestone on water. Despite having invented one of the best tools for navigation, sailors didn't use his invention for over 300 years. Early explorers, using the same idea, carried around lodestone to magnetize needles for use as a compass. It wasn't until later that inventors made a liquid-filled, enclosed compass. Using Styrofoam, you can recreate Peregrinus' early compass.

Things You'll Need

  • Scissors
  • Styrofoam
  • Pie plate
  • Water
  • Strong magnet
  • Needle
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Instructions

    • 1

      Cut a piece of Styrofoam into a thin circle with a 1.5 inch diameter. It should be thin enough to float in water like a leaf in a calm pond.

    • 2

      Fill a pie plate with water.

    • 3

      Rub the end of a needle with a strong magnet. Only rub in one direction and rub it 60 times. Afterward, check to see the rubbing magnetized the needle by placing it near something made from steel. If not, rub it until magnetized.

    • 4

      Float the Styrofoam in the center of the pie plate.

    • 5

      Set the needle on the Styrofoam's center.

    • 6

      Watch as the needle aligns with Earth's magnetic north-south field.