Build a Compass
A compass is a navigation tool that shows direction (north, south, east, or west). They have been used for many years by people trying to find their way. In this activity, you will get to make a compass and explore why they need magnets to work.
Activity Type:
Hands on activity, experiment
Suggested Age:
6 to 9 years old
What you need:
Sewing needle
Small bar magnet
Piece of cork or Styrofoam disk
Bowl of water
Nail polish
Tape
What you do:
Paint one end of the needle with a dab of nail polish.
Run the south pole of a magnet over the needle from the unmarked end to the marked end about 50 times. Be sure to lift the magnet each time and always move in the same direction. This action magnetizes the needle.
Put the needle on the Styrofoam disk or small piece of cork. Add a small piece of tape to secure it. Or stick the needle through the Styrofoam.
Float the Styrofoam disk in a bowl of water.
Watch what is happening to your compass. The needle should come to point towards the nearest magnetic pole — north or south as the case may be.
Test this by using a compass. Don’t have a compass? Use the app on your mobile device.
Explanation:
The earth produces a magnetic field. This field, although weak, is sufficient to align iron and other paramagnetic compounds that are within the sewing needle. By floating the needle on the cork, it floats freely, and can orient itself within the Earth’s magnetic field, to point toward the north or south poles of the planet.
History:
During the medieval period, most people navigated using the sky, by the stars, moon, and sun. The introduction of the compass was based on this simple floating compass. As improvements were made in navigation such as Portolan charts, people were better able to navigate, even when the sky was cloudy. This allowed for more travel, especially sea travel, during all seasons.
Taking it further:
Why did the magnet have that effect on the pin? Think about early forms of navigation such as this compass. Do you think it would be difficult to find your way?
Do you have a GPS? Go for a walk using the GPS to navigate your walk. What are the benefit of GPS technology compared to a compass?