Magnets: Powerful Servants of Man

Published 10:36 pm Monday, April 9, 2007

By By Seth Rabon
Did you know you could be using a magnet right now and not even know it? For a 7th grade homeschool project I decided to do research on the magnet. I hope you will enjoy what you are about to read.
Magnetism- what would life be like without it? It brings us electricity, warms our homes, lights our roadways and cooks our food. How could we enjoy the radio, television programs, or talk on the cell phone if it was not for the magnet. I learned a long time ago that the Chinese called it "the stone that licks up iron." Sailors gave it the name lodestone that means, "The stone that leads." Columbus also used it when he crossed the Atlantic Ocean. We call it the magnet, which came from the ore magnetite, which was plentiful in Magnesia, a district in Asia Minor. Loadstone, or magnet, back then was as precious as gold, even kings were fascinated by it. Today it is easy to obtain a magnet. Man-made magnets of great strength are easy to buy for a small price. But what is magnetism? How does it affect us? What is the source of this mysterious power? Let's take a closer look at the magnet.
Some of us have heard about the magnetic field, here is an experiment! Lay a piece of paper over a magnet and sprinkle some iron filings onto the paper. Tap the paper a few times; this will cause the fillings to form a strange pattern. The metal fillings seem to loop out of one end of the magnet and into the other that is just a small part of the magnetic field. The areas on each end of the magnet where all these converge are called poles. Every magnet has two poles that cannot be separated from each other. For example, if we were to cut our bar magnet into two parts, we would not have two half magnets, we would have two complete magnets, each having two poles just like the original magnet.
Let's observe another very interesting property of the magnet. Tie a sting around the middle of the magnet and suspend it into the air. Notice that one end of the magnet will swing around until it points to the north. Take it away and notice it will always swing back to the north. The pole of the magnet that points north is the north seeking pole. That is the property of magnetism that is the basis for the compass. The earth itself has a magnetic field just as the bar magnet has. This field extends far into space and converges at each end of the earth's poles. So a magnet's north-seeking pole will always be attracted by the North Pole of "magnetic earth" while being repelled by the South Pole.
Probably the most familiar characteristic of magnetism is the ability to attract metals. Not all metals are drawn to a magnet however. Brass, aluminum, gold and silver are not attracted. Whereas iron, nickel, cobalt, chromium and other metals are attracted, though in varying degrees.
Interestingly, the attractive power is the same on both sides of the poles. An iron nail, for example, will be attracted just as strongly by either end of a bar magnet. What is the source of this power? Just what causes magnetism? And why are not all metals magnetic?
The source of its power is the atom. It contains a tightly packed nucleus made up of protons and neutrons with varying numbers of electrons circling around it; much like the planets in our solar system orbit the sun. This movement of electrons actually results in a minute magnetic force within the atom. When electrons are paired so that they face different directions, they cancel out each other, so the net magnetic field is zero. Metals like brass, aluminum, gold and silver are non-magnetic.
However, when all electrons in the atom are facing the same direction, they can attract like nickel, iron, cobalt and other irons. Here is a simple illustration- imagine two kids trying to pull the wagon, one pulls from one side and the other pulls from the exact opposite side. What happens? The wagon does not move! Then the two kids realize that it is not working so they switch positions. They both pull from the same side and it moves! That is how magnetism works!
As mentioned earlier, the earth itself is one large magnet. Some have thought that it was caused by the naturally magnetic cores within the earth, but in more recent times it has been learned that the very high interior temperature of the earth rules out that possibility. Today, the most commonly accepted explanation is that our globe's magnetic field results from the electric currents in the earth's core, which is in some way related to the revolution of the earth on its axis. There is evidence also that other planets are magnetic. Jupiter, in particular, has a field much stronger than the earth's. Also, the sun itself has an extremely powerful magnetic field. Even the Milky Way, the galaxy that contains our sun and some billions of stars, gives evidence of having a magnetic field.
One of the main reasons that the earth has this magnetic field is for our protection. The sun sprays into space streams of electrically charged particles, which are called solar wind. This wind would be devastating to the atmosphere; however the earth's magnetic field bends their paths into spirals around the lines of magnetic force and funnels them into the atmosphere to the North and South Polar regions. This protects us from the most damaging cosmic waves by diverting them to these polar latitudes. It is evident that the magnetism of our planet plays a key role in protecting life.
There are many things yet to be learned about magnetism, and the more scientists learn about this power, the more uses they find for it. For instance, industry and business: magnets in electric motors help run almost any machine that makes something move or rotate. Theses devices include cranes, cutters, fax machines, machine tools and printing presses. Magnets in computers store information on magnetic discs. Powerful electromagnets attached to cranes move scrap iron and steel and separate metals for recycling. Generators in power plants rely on magnets similar to those in electric motors that produce electricity. Devices called transformers change the high voltage electricity carried by the wires to the lower voltage needed in homes and businesses.
In transportation, all electrified transportation systems depend on magnets in electric motors. These include trains, subways, trolleys, monorails, cable cars, escalators and moving sidewalks. Electric motors operate windshield wipers, electric windows, doors, door locks and other devices in cars, buses and airplanes. Electromagnets also produce radio waves in radar systems, an important navigational aides for ships and airplanes. Also, scientists and engineers have developed trains that use electromagnets to levitate (float) above a track without touching it. These trains eliminate the friction of wheels on the track and thus can move at much higher speeds than ordinary trains do.
Furthermore, magnets are very useful in science and medicine. For example, electromagnets in electron microscopes focus a beam of electrons on a sample to be studied. Powerful magnets, called bending magnets, help control beams of atomic particles that have been boosted to high speed in devices called particle accelerators. In nuclear energy research, physicists make the nuclei of the atoms fuse (unite) in extremely hot gases called plasmas. Plasmas are so hot that they would melt walls of any container made of ordinary materials. Physicists hold the plasmas away from the container walls in a strong magnetic field that functions as a "magnetic bottle."
Also, there is a technique known as an MRI where the patient lies inside a large cylindrical magnet. The MRI uses magnetic fields and radio waves to produce images of the head, spine, internal organs and other parts. Other diagnostic devices help physicists to observe magnetic fields generated by the brain, heart and other internal organs.
In conclusion, I have enjoyed learning how magnets work, and how the earth has a magnetic field that protects life. Also, magnetism is beneficial for transportation, electricity, appliances in our homes, communication, science and medicine. Truly, magnets are a powerful servant of man!

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