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Magnets If your refrigerator is like mine, it is covered by notes and pictures and drawings. But, how do all of these things stick to the front of my refrigerator?

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Presentation on theme: "Magnets If your refrigerator is like mine, it is covered by notes and pictures and drawings. But, how do all of these things stick to the front of my refrigerator?"— Presentation transcript:

1 Magnets If your refrigerator is like mine, it is covered by notes and pictures and drawings. But, how do all of these things stick to the front of my refrigerator? I bet you guessed! Magnets! Let’s investigate! Magnets are so neat, but where did they come from? Well, magnets were discovered thousands of years ago by the ancient Chinese. These ancient people found a special kind of rock in their fields. This rock could pull small pieces of iron towards it and the iron would stick to the sides of the rock like magic. Well, it seemed like magic to the ancient Chinese, but we know that what they really discovered was a special rock called a lodestone. This kind of rock acts just like our refrigerator magnets. Today many magnets are man- made by scientists. Magnets have been around for a really long time, but what are they and how do they work? A magnet is an object that is able to pull other objects towards it. If the object is pulled too close, it will stick to the magnet. This pulling is called attraction. Magnets are attracted to other magnets and some metals like iron.

2 Just like the Earth, every magnet has two ends called poles. One end of a magnet is called the north pole and the other end is called the south pole. If you put two magnets beside each other on your desk, the north pole of one magnet will try to stick to the south pole of the other magnet. They are attracted to each other. But, if you try to stick the south pole of one magnet to the south pole of the other magnet, they will push away from each other. The same thing will happen if you try to stick the north pole of one magnet to the north pole of the other magnet. If magnets push away from each other, we say they repel. Did you know that magnets are all around you? In addition to the magnets on your refrigerator, the following objects also contain magnets; chalkboard letters, paperclip holders, cabinet door latches, toys that run on batteries, and compasses.

3 Do you know what a compass is? Soon after the ancient Chinese found the magnetic lodestone rocks in their fields, they discovered that if they rubbed a metal needle against a lodestone, the needle would turn into a magnet. They then discovered that if they tied a string around the middle of the needle magnet and let it hang down from their hand, one end of the needle always pointed north and the other end always pointed south. They had invented the compass! People soon began to use compasses to travel from place to place. By using compasses, people could figure out in what direction they were headed. Christopher Columbus used a magnetic compass to cross the huge Atlantic Ocean and discover America. Wow! Aren’t you glad that the Chinese invented the compass? Christopher Columbus might not have discovered America without it!


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