Try This at Home: Beakman's Motor
Illustrated Concepts
Electricity is the movement of tiny negatively-charged particles called electrons. Electricity and magnetism are interrelated. Electricity can induce magnetism and magnetism can induce electricity. Electricity has a wide range of uses, including turning motors and powering lights.
What You Need
- ~ 1 meter (1 yard) insulated wire
- 2 paper clips, uncoated metal
- 1 D cell battery
- 1 large rubber band
- 1 ceramic magnet, preferably rectangular
- Scissors or wire strippers (or sandpaper if wire is enamel-insulated)
What To Do
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Make sure you have an adult with you to supervise this experiment.
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Starting 5-10 cm (2-4 inches) from the end, wrap the wire around the battery about 7 times. Directly opposite from the starting point, leave an unwound tail of wire about the same length as the other.
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Slide the coil of wire off the battery. Wrap the tails around the coil a few times to hold it together.
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Strip the insulation completely off one tail. On the opposite tail, carefully strip the insulation off just the top half of the tail. If you are using enamel-insulated wire, sand the insulation off with sandpaper. Alternatively, you may choose to strip the insulation completely off both sides, and then put several layers of waterproof marker (e.g. a Sharpie) over half the wire on one tail in order to re-insulate it.
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Wrap the rubber band around the battery lengthwise twice. Straighten the larger loop on the two paper clips. Insert one paper clip under the rubber band at each pole of the battery so that the loops stick out in the same direction. Make sure the paper clips have good contact with the battery poles.
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Stick the magnet to the battery between the two paper clips.
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Put the tails of the wire coil in the paper clip loops so that it hangs freely. Gently nudge the wire coil in one direction to get it spinning. It should continue to rotate on its own. If it doesn't spin, check the connection between the paper clips and the battery. Use caution; the battery may get hot.
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Now you have made a motor that runs on electricity. How do we use electric motors in our daily lives?
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Clean up.
What's Happening
When the un-insulated sides of the wire make contact with the paper clips, a direct electric current flows from the battery through the paper clips and through the wire coil. The electric current flowing through the wire coil creates a magnetic field. This field causes one side of the coil to become a north pole and the opposite side to become a south pole. The permanent magnet attracts the opposite pole of the coil and repels its like pole, causing it to flip over. However, when the insulated side of the wire contacts the paper clip, the current can't flow through the coil and it is no longer magnetized. Thus, the attractive force to the magnet no longer exists, and inertia keeps the coil rotating in the same direction until the un-insulated side makes contact again, restarting the magnetic attraction.
Fun Fact
Sharks have special organs that detect electrical charges in the water to help them find their prey!