Weird Science: Needle Compass - Hawaii News Now - KGMB and KHNL

Weird Science: Needle Compass

HONOLULU (HawaiiNewsNow)- Dr.V and Taizo Braden are back at the Honolulu Theater for Youth. Let's see how a compass works and how you can make one.

 Things you will need:

  • Glass bowl
  • Water
  • Sewing needle
  • Magnet
  • Tissue paper

The Experiment:

Fill your glass bowl with water. Run the magnet over the needle, always running it along the needle in the same direction and not back and forth. This will magnetize the needle and align the magnetic parts of the needle in one direction. Lay a small piece of tissue paper on the water and carefully float the needle on the tissue paper. Your tissue paper will slowly sink down into the water, leaving your needle floating on the surface of the water. The needle floats using the surface tension of the water to hold it up. Watch what the needle does. (Make sure you put the magnet down far away from your bowl of water.) If you have a compass, you can check your needle compass to see if it is correct.

How does it work?

The earth produces a magnetic field. It has a dense iron core that gives off a magnetic field. So your magnetized needle, which can rotate freely on the surface of the water, will align itself up with the earth's magnetic field. Try bringing your magnet close to the needle and see how it behaves. Then when you move it way, does the needle reorient itself again?

Before we had GPS (Global Positioning System), people would use compasses to navigate. The Polynesians would navigate using the stars as well as the ocean. You can learn much more at the Honolulu Theater for Youth's upcoming production, "Navigator." Combining hula, chant, history and hard science, this production explores ancient and modern stories of navigation. Questions of identity, geography and history collide when two young women, one modern and one ancient, find themselves wrestling with the starts and sea to discover their place in the world.

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