Magnetism

Magnetism: A Homemade Electromagnet


Equipment

  • iron nail
  • a long wire, enough to completely wrap the nail with
  • a battery and battery clip
  • a resistor (See Notes and Safety below)
  • several small paper clips, magnets, a compass or whatever magnetic materials you have on-hand

Description

The wire is wrapped around the nail as many times as possible. Then one end of the wire is attached to one lead of the battery clip while the other end of the wire is attached to the resistor which is then attached to the other end of the battery clip. Once the battery is put in the clip, the nail will act as a magnet, with one end a north pole and the other a south pole.

Any wire emits a magnetic field, even long straight wires or a coil of wire without the nail. You should find that the magnet is strongest with the nail in place. The reason is that, in the presence of the magnetic field of the wire, the iron magnetizes.

Notes and Safety

  • You could try this experiment without the resistor. If you do this, beware! The wire will tend to get quite hot and could potentially burn.

Possible Background Demonstration

  • Try the same experiment without the nail.

Follow-ups

  • Do this with a compass to show that the Earth has a magnetic field and that a compass just points in the direction of that field.
  • Faraday's law: Lighting a lamp