(EEM) Magnetism Lesson

Magnetism

You have probably used a magnet before to place a note on the refrigerator or to navigate with a compass while walking in the woods. Magnets seem simple at first, but they have properties that make them different from other materials. Magnets exhibit a magnetic field that can act upon other substances. Ferrous (ferrum=iron) materials, using iron as a base, may include a lot of different metallic elements. Some examples are chromium, nickel, molybdenum, vanadium, manganese. Those allow ferrous materials to respond to a magnetic field while other substances are unaffected. This has to do with the arrangement of electrons in the material.

If a magnet can cause the electrons in a material to orient in one direction, then a material is considered to be magnetic, and attraction occurs between the material and the magnet. There are two classes of magnets, permanent magnets, and temporary magnets.

A permanent magnet will retain its magnetic properties for a long period of time and can either occur naturally or created by man. Permanent magnets are made from materials that retain a certain crystalline structure that causes atoms to align in certain ways. This alignment gives the magnet its properties and allows for attractive forces to form between it and ferrous materials.

Temporary magnets can be created by man, by running an electric current through a coiled wire. These temporary magnets are called electromagnets and can be controlled very easily by using a switch to cut an electric current on and off. These are useful in separating metals in a recycling facility, in generators and in electric motors. Magnets are also used to generate electricity by moving the magnets near a coil of wire. This is how turbines generate the electricity that we use in our homes every day.

Every magnet, both permanent and temporary, has two poles that show similar characteristics. These poles are known as north and south, based on the largest magnet of all, the Earth. As the North Pole and the South Pole of the Earth have similar but opposite magnetic properties, so do other magnets. The opposite poles of two magnets attract each other, but their similar poles repel one other. If you place two magnets side by side, they will orient themselves where the opposite poles are side by side. This is due to the attractive and repulsive forces produced by the opposite poles of a magnet. Even if a magnet is broken, new poles arise at the broken ends so that each new piece has a pair of north and south poles.

There are many uses for magnets in our everyday lives. Magnets are in the speakers of our stereos, televisions and cell phones. They are used in scrap yards to separate ferrous metals from nonferrous metals. Magnets are also found in computers where they are responsible for storing data on hard drives and other forms of data storage. We use simple magnets to fasten materials together that need to be easily separated. I am sure you have used one of these type magnets to attach something to the refrigerator or a metal cabinet. Magnets are also used in ignition systems for cars and other vehicles where they act as a switch that controls current flow.

Without magnets our lives would be very different. In fact, we would probably not be here at all. The Earth is one large magnet and the magnetic field that it produces protects us from harmful rays generated by our sun. They are deflected as they approach Earth by its magnetic field and move into outer space instead of entering the atmosphere and killing all forms of life on the planet. As you can see, magnets are everywhere, and these are just a few applications that we use every day.    

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