Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!
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Answers:
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1. If you moved that magnet back and forth along a wire-wrapped nail fast enough you could power a light bulb. (However, by fast enough, I mean like 1000 times a second or more!)
2. A magnet that you can turn on and off using electricity. An example is a nail wrapped in a coil of wire, powered by a battery pack.
3. The coil is magnetized (becomes an electromagnet) and is momentarily attracted to the permanent magnet and starts to align itself with it, but as it does, it breaks the connection and the coil becomes just a piece of unmagnetized wire, which continues to rotate from the previous pull (when it was magnetic). As it does, the coil energizes again, now repelling itself and pushing itself away as it tries to align itself with the magnet again, and as it does, the electricity goes off again, allowing the coil to rotate freely (and not get stuck in one position). And on it goes.
4. It’s a switch that connects (turns on) when a magnet is close by. The two small steel plates hit each other and allow electricity to flow.
5. Magnetism can create electricity and electricity can create magnetism. Sound is vibrations. To make a speaker, we need to somehow make something vibrate. The radio provides the electricity that gets pumped through the wires. The radio very quickly pumps electricity in one direction and then switches to pump it in the other direction. This movement of electrons back and forth creates a magnetic field in the coil of wire. Since the electricity keeps reversing, the magnetic field keeps reversing. Basically, the poles on the electromagnet formed by the coil go from north to south and back again. Since the poles keep reversing, the permanent magnet you have taped to the cup keeps getting attracted, then repelled, attracted, then repelled. This causes vibrations. The speaker cone (or cup, as in the speaker we’re going to make) that’s strapped to the coil and magnet acts as a sound cone. The magnet causes the sound cone to vibrate and since it’s relatively large, it causes air to vibrate. This is the sound that you hear.
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