The History of Magnetism

Compass made with home materials
A compass made with materials found around the home.

… and how to make a compass using material that is found in most homes.

Materials

  • Magnet (a refrigerator magnet will work!)
  • Twist-Tie (like you might use to close a bread bag)
  • Straight sewing pin
  • Piece of heavy cardboard

Background

Human knowledge of magnetism began with magnetic stones. Prehistoric people observed that certain stones were attracted to each other and that iron was attracted to them. They discovered that if one of these stones is suspended so that it can turn freely, it always turns to a certain position. By noting the position of the stone the stone could be used to determine which direction is north without observing the North Star. In English such a stone came to be called a lodestone. In ancient Greece, a particularly good type of lodestone was called magnetite because it was found in an area of Greece called Magnesia. The word magnet came from magnetite. We now know that magnetite is an iron ore that has become naturally magnetized.

Ancient people made compasses in several ways including magnetizing iron needles. There are also several ways to make a compass at home. A compass requires something fairly light that is either a very small magnet or something light that can be magnetized using a permanent magnet. Most homes have refrigerator magnets, cupboards with magnetic latches or a screwdriver that has a magnet in it. A cupboard-door magnet can be used without removing it from the door.

Make your own compass!

Step 1:

Magnetize the twist-tie by stroking it with one end of a magnet from the center toward one end several times as shown below.

Step 2:

A 4-inch square piece of heavy cardboard is required for the base. A straight sewing pin is required for the compass needle to pivot on. Draw a circle on the cardboard and mark it with the points of the compass as shown. Insert a straight pin from the back side of the cardboard.

Carefully measure the twist-tie and mark the center. Bend a flat-bottom “U” shape in the center as shown. The “U” must be deep enough so that the twist-tie can be balanced on the pin and turn freely without touching the cardboard. When you have successfully balanced the twist tie it should point north.