Physics

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Video

Materials

• 1 large iron nail
• A 1.5 V battery (size doesn't matter)
• 1 electric wire, about 75 cm (30 in) long
• 1 cutting pliers
• Small metal objects (such as paper clips or staples)
• Tape

Explanation

There is a close connection between electrical and magnetic phenomena. When a current is led through a wire wound like a coil, the coil will act as a magnet. One end of the coil becomes the north pole and the other becomes the south pole - just like on a regular magnet. By placing iron, or some other so-called ferromagnetic material, in the center of the coil, the magnet gets stronger.

This device is an electromagnet, i.e. a magnet that only works thanks to an electric current.

Be aware that the wire can become quite hot and that the battery discharges fairly quickly. Therefore, when using the electromagnet, break the circuit by disconnecting the wire from either the positive or negative terminal of the battery.

Experiment

You can turn this demonstration into an experiment. This will make it a better science project. To do that, try answering one of the following questions. The answer to the question will be your hypothesis. Then test the hypothesis by doing the experiment.

• What happens if you wrap the wire more times around the nail?
• What happens if you use a thicker wire?
• What happens if you use a thicker nail (or some other iron object that is thicker)?
• What happens if you if you use a longer nail (or some other iron object that is longer)?
• What happens if you use another battery?
• What happens if you use multiple batteries? (Connect batteries in series by placing them in a row, positive terminal to negative terminal. Place one end of the wire against the free end of the outermost battery on one side, and the other end of the wire against the free end of the outermost battery on the other side. Pay attention to if the wire gets too hot - it may then start to burn.)

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