A magnetic field is a directional force attracting ferromagnetic materials such as iron. This may be a natural characteristic of the host material. However, it is possible to induce it in a suitable object using an electric current. This post explains how to build an electric magnet using simple materials. However, we do need to delve into the science behind it first.
Basics to Know Before Building an Electric Magnet
An electric current passing through a wire wound into a coil creates a magnetic field when the power is on. This force concentrates in the center of the winding, but vanishes if we turn the electricity off.
Electrical engineers often make these wire turns around ferromagnetic materials such as iron, and iron alloys. This concentrates the magnetic flux through the surface, and makes the force more powerful. In this experiment, we build an electric magnet to illustrate this principle.
You will need the following materials if you would like to give this a try:
- A new, fully charged nine-volt battery for a radio or similar
- A responsible adult to watch over you for safety’s sake
- A short length of insulated copper wire with both ends bare
- A large iron nail, plus small paper clips or other metallic objects
Procedure to Make a Ferromagnetic Magnet
PHASE ONE
Wrap the wire a couple of turns around the nail tightly as you can. Touch the bare ends to the battery terminals. Is the magnet strong enough to pick up a paper clip? Be careful. The battery can get warm!
PHASE TWO
Wrap the wire tightly, but this time with more turns. What happens now, can you pick up more paperclips? Is the battery hotter this time? Experiment with different-size nails, and nails of different iron alloys. What changes?
EXPLAINER
The battery supplies the electrons for the experiment. When we connect the two ends of the wire to the terminals, a current flows through it. The electrons create a magnetic field in the heart of the coil. Thus turns the nail into a magnet strong enough to pick up a few paperclips.
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