 Hi, I'm Ashley from the North Carolina School of Science and Mathematics. Today, we're going to learn about magnets and do some experiments to understand how and why they work. We'll learn about one of the most familiar tools involving magnetism, a compass. And finally, we'll build a simple electromagnet. You should come away with a better understanding of magnetism and the way we use electromagnetics in our everyday lives. We'll start by looking at these two simple bar magnets. What do you notice about them? First, you'll probably notice they're made of metal. Now look at the ends. Do you see the markings? Take these two bar magnets and bring the two ends marked with the letter N close together. Do you notice something? The two ends marked with the letter N tend to repel or push each other away. Try the same thing with the ends marked with the letter S. So, we now know that the ends of a magnet marked with the same letter repel each other. Now turn the magnets so that the letter N and the letter S point towards each other. They move together. Opposite ends of the magnet attract each other. Those N and S markings define the north and south poles of the magnet. The poles are where the magnetic field lines converge or come together. Just like our Earth, which has a north and a south pole, each and every magnet has at least two opposite poles. Did you know that if you were able to take your magnet and break it into two, new poles would appear on the cut ends? The new smaller magnets you made would have north and south poles just like the original magnet that you cut in half. You can't have a magnet with just one pole. Let's go back to the attraction of different poles. Did you notice if the magnetic force changed as you move the opposite poles nearer and further apart? As the opposite poles get closer, the pole forces get stronger until the two magnets are drawn together. Magnetic forces can be quite strong and can even act through other solid materials. Not every item has magnetic properties. Most magnets contain a mineral called iron, which gives the item its magnetic properties. Not all magnets are shaped like a bar magnet. Others are cylindrical. Some are disc shaped and some shaped like a horseshoe. We saw where the poles were in the bar magnet, but where would they be on this horseshoe magnet? First, let's start with the familiar bar magnet we've worked with. We'll pull the bar magnet behind a sheet of paper and add some iron filings on the surface of the paper. Do you think you'll be able to identify the poles of the magnets? The poles are where the field lines converge or come together. Doing the same experiment with other types of magnets show us where their magnetic poles are located. Does a disc magnet remind you of something you've probably seen before? It reminds us of the magnetic poles of our own Earth. We're not talking about geographic north and south poles. The Earth rotates once each day around an axis, and at the end of the axis are those geographic poles. The magnetic north and south poles are slightly different than the geographic poles, but we can use a compass to point toward the northern magnetic pole, giving us a general northerly direction. Those magnetic poles are very strong and can aid us in finding directions of travel. Take a look at a magnetic compass. The needle pointer is made out of a magnet that rotates and act like a pointer. Making sure any other magnets are not close by, move the compass around to get the needle to rotate freely. Rotate one way, then another. The needle will return to the same northerly direction. Turning the compass to correspond to the direction in which the needle points shows us the direction of the northern magnetic pole of the Earth. If you don't have a magnetic compass, you can make one with a magnet and some string. All you have to do is hang the magnet on a string. The magnet will eventually align itself with the magnetic poles of the Earth just like the compass we saw. So far, everything we've been talking about has to do with natural magnetism. The bar magnet was made of a kind of iron that is ferromagnetic or naturally magnetic. Some materials, like those making up this nail, aren't naturally magnetic, but the nail can become temporarily magnetic. Try this experiment. Rub the nail along the length of the magnet and try picking up the paperclip. The magnetic properties we've given the nail with the magnet will weaken after a while, but it shows that some materials can take on magnetic properties with a little help. There's another way to make the nail magnetic. We'll do it by sending electrical current through a wire. First, let's begin with an observation. Try to pick up the paperclips with the wire wrapped nail. What happens? Next, take a wire wrapped nail and using the alligator clips, attach a battery pack. Now, we'll try picking up the paperclips. What do you think might happen if the electrical current stops? Do you think the nail would hold onto its magnetic properties? Let's disconnect the battery and see. As before, the nail kept some of the magnetic properties after it was wrapped with the wire and an electrical current was run through it. This makes what is known as an electromagnet. Electromagnets can be very powerful and can have lots of uses. Now, let's put what we learned to use. We're going to make a motor. If you want to make one too, you'll need a D-sized battery, two large paperclips bent like this, a button magnet, and a coil of wire like this one. We place the magnet on the battery and the paperclips in this position. The coil is placed in the paperclip supports. With a bit of finesse, the coil will start rotating, making a simple electric motor. Electrical energy and magnetic energy work together. The magnet pushes on the current and the wire to make it rotate. The energy of this rotation can be harnessed to do work for us. You can harness the power of electric motors like this to make all sorts of things work, like blenders, canopiders, and vacuum cleaners, anything that rotates and uses electricity. They're bigger and more powerful than the one we made today. Today, we learned about natural magnets. We learned about the natural magnetic properties of the Earth and about magnetic poles and how a compass works. We also learned about electromagnets, how they work, and how to make them. I hope you have a better understanding of magnetism and go on to learn more about the many ways magnets can work for us in our everyday lives. Thanks for watching!