|An aluminum ring is launched off of an electromagnet. With the iron bar in the electromagnet, it goes even higher.
An electromagnet is just a coil of wires with a current running through it. Electrons are like tiny magnets and when they move (as in a current), they create a magnetic field. The iron core increases the magnetic field of the electromagnet. The ring feels a greater magnetic force, which pushes it higher. The colder the ring it, the less resistance there is and the more current can flow through it. More current means a bigger magnetic field and the ring goes even higher!
When you add an additional iron bar into the electromagnet, it increases its strength. (This is why we used a nail in the previous electromagnet experiment.) A stronger magnet makes the ring jump much higher! If you add a second ring, you might expect it not to go as high because there is twice as much mass. But, there is also twice as much ring to turn into a magnet that will be repelled and it launches just as high.
We can make the ring jump much higher by using liquid nitrogen to make it very cold. When things are very cold, electricity can flow more easily. Since the electricity can flow through the ring better, the ring becomes a stronger magnet and jumps a lot higher.
If the ring gets cut, it won’t jump. We said some of the electricity in the wire gets into the ring to make it into a magnet. But, electricity has to flow in a complete circle to make a magnet. Since there is a cut, the electricity can’t get all the way around. The cut keeps the ring from turning into a magnet.