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Direction of Magnetism


Quinn

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A tool that provides direction by the use of magnetism is based on the basis of physics. This tool, the compass, has been used for many centuries and helped guide history through various explorations. Today, this tool is not used as much as it had been in the past but if you are ever lost it is a great instrument to help you find your way.

Magnetism is one of the first bits of science students learn about in school and just about the first thing we discover is that like poles repel opposite poles attract. If you hold two bar magnets so their north poles are almost touching, they will push away from one another; if you turn one of the magnets around so one magnet's north pole is near the other magnet's south pole, the magnets will pull toward one another. That's all there is to a compass: the red pointer in a compass - the magnetized needle - is a magnet and it's being attracted by Earth's own magnetism called the geomagnetic field. Earth behaves like a giant bar magnet with one pole up in the Arctic and another pole down in Antarctica. Now if the needle in your compass is pointing north, that means it is being attracted to the Earth's north pole. Since unlike poles attract, the compass is being attracted to must be a magnetic south pole. Furthermore, the thing we call Earth's magnetic north pole is actually the south pole of the magnet inside Earth. Originally this concept was a little challenging to grasp but then I realized all I need to remember is that opposites attract. Earth's magnetic field is actually quite weak compared to forces like gravity and friction. For a compass to be able to show up the relatively small effects of Earth's magnetism, the effects of these other forces must be minimized. That is why compass needles are lightweight and mounted on frictionless bearings.

Compasses provide direction to our destination which in the end can be more useful than most other instruments we use in our daily lives.

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