Laboratory - Magnetic Relaxation
Build An Electromagnet
An electromagnet is a device that uses an electric current to generate a magnetic field. It is generally made by coiling electrical wire around a core of iron or steel. Nickel and cobalt may also be used.
Tools & Materials
- Small 1.5 volt battery
- 1 meter (about 3 feet) of 22 gauge insulated wire
- An unfolded paper clip
- Wire strippers
- About a dozen staples
What to do:
- Unfold one paper clip.
- Put tape around one end so you can distinguish which end of the paper clip is which. This is not necessary for objects that have a definite "top" and "bottom" like a nail.
- Remove two or three centimeters (about an inch) of the insulation at each end of the wire.
- Wrap the paper clip snugly with the wire. Start about 15 cm (6 inches) from one end of the wire. Make small concentric loops starting at the taped end of the paper clip. Continue until you have reached the bottom tip of the paper clip.
- Connect the one end of the wire closest to the tape side of the paper clip to the positive terminal of the battery.
- Connect the other end of the wire to the negative terminal of the battery for about 10 seconds. Warning: If the wire gets hot to the touch at any point, immediately disconnect the wire from the battery!
The paper clip is considered to be an electromagnet as long as there is current running through the wire. To see if it is magnetized, you can try to pick up some staples with it. When you disconnect the battery, what happens?
Other objects made of iron, steel, nickel or cobalt may be used to make an electromagnet, but we found that the paper clip works especially well for the relaxation experiment to follow.