Magnetism is a property of matter, like density or luster are properties of matter. Magnetism depends upon the type of material being used. Materials like iron, cobalt, and nickel are great for magnetism.
Basically, for a material to be magnetic, the electrons in the metal just need to line up and face the same direction. This is called a magnetic domain. If they do this and hold their position, then they create a force of magnetic attraction. There is an area around a magnet where the force exists, and that is called the magnetic field.
There are two ends of a magnet. If you think of the electrons as people, it makes some sense. If all the people line up facing one direction, then all the fronts are facing one way and all the backs are facing the other way. In a magnet, these differences are called magnetic poles. Poles of like charge repel, whereas poles of opposite charge attract. This is because the electrons want to face the same direction, so if you make two parts face each other, they push away.
You can create a temporary magnet, called an electromagnet, by using electricity and magnetism together. If you put a conductor inside a coiled wire, when you put current through the wire, the conductor will temporarily become a magnet. It’s really easy to do. The electrons going through the coil of wire have an effect on the conductor in the middle and that makes the electrons face the same direction. When you stop the electricity, then the electrons go back to their regular places and the magnet stops being a magnet.
Some devices, like a maglev train, work on electromagnets. For a maglev train, there are massive electromagnets that keep the train hovering in the air. This gets rid of friction that usually exists between the wheels and the rails. Maglev trains can go super fast! They are expensive to build and maintain, though, so it will be a while before they’re everywhere.
To create an electromagnet, you need to have electricity, which is the flow of electrons through a conductor. You can create a flow of electricity using alternating current or direct current. Direct current was invented first, and it’s the kind of energy that a battery creates. The energy comes out one side and always goes through the circuit and into the other end of the battery. This is fine for small amounts of energy, but something more complicated is needed for bigger things.
Alternating current was invented later and if you think about the name, it’s pretty simple. The current alternates. It’s that easy. The electricity goes in one way for a bit, then it changes direction and comes back. This allows more energy to go through a circuit. It’s like brushing your teeth; you clean off more if you brush back and forth than if you just brush forward.
Electricity can be used to move things. But moving things can also be used to create electricity. A motor in a car, for instance, uses energy from a battery to make mechanical energy, which eventually lets a car move. On the other hand, you can turn a hand crank using mechanical energy in order to generate electricity. Generate? Yes! It’s called a generator when you use mechanical energy to make electrical energy.
There are also devises called transformers that use coiled wires to increase the voltage in a circuit. It’s like making a fort in the snow and then you want it bigger so you add more snow. A transformer changes the amount of voltage. Power lines carry a very high current through the neighborhood, but if that energy reached your house, your house might be in danger! A transformer reduces the current reaching your house so you’re safe.
Finally, we know that insulators stop electricity (like a red traffic light), resistors slow down electricity (like a yellow light) and conductors let electricity flow freely (like a green light). But all materials have some resistance, except for a superconductor, which is a special type of conductor that has practically no resistance! You can get a lot of electricity through with one.
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