Any object with a magnetic field is known as a magnet. A magnet naturally attracts ferromagnetic materials such as iron and cobalt. Refrigerator magnets and compass are the two most visible uses of magnets in our day to day life. However, they are also used in microphones, speakers, headphones, ATM and debit cards, electric guitars, computer hard disks, TVs, monitors, and other objects that we use regularly. For children, a magnet is perhaps the closest they ever come across what seems like magic in real life. Magnets are not only useful, they are also interesting. The following are five of the more interesting facts about magnets:
1.Permanent magnets have been used and studied since ancient times. The ancient Greeks, Indians and Chinese knew about the magnetic properties of the naturally occurring mineral we know as lodestone. Lodestone is magnetised iron ore, and acts as a permanent magnet. Thales (624 BC – c. 546 BC), who lived centuries before Aristotle and was called by the latter as the “first true philosopher”, studied the magnetic properties of lodestone. The ancient Chinese knew about the magnetic properties of naturally occurring permanent magnets as early as 3rd century B.C. They were also the first to use a magnetized compass.
2.The name magnet is derived from Magnesia, which is a region in Greece. Magnesia was the primary source of lodestone for ancient Greeks, so the ancient Greeks started calling their lodestone as magnet, which means “stone from Magnesia”. The word was borrowed by modern European languages such as English and German, with the result that most modern European languages use the same word for magnet – magnet.
3.Permanent magnets can be easily demagnetized by heating them above a temperature known as its Curie temperature. A Curie temperature for a ferromagnetic material is the temperature above which it loses its magnetic field. For Iron, the Curie temperature is 770 degree Celsius.
4.The Earth itself has a permanent magnetic field, and is the largest permanent magnet we know. Earth’s magnetic field is caused by electric currents in the molten iron present in Earth’s outer core. The outer core is a liquid layer 2,266 km thick and starts 2,890 km below the surface of the Earth. When a compass points towards north, it does so because its magnetic head is attracted by Earth’s magnetic north pole.
5.The most widespread type of magnet used in the present day is the electromagnet. In an electromagnet, the magnetic field is produced by the flow of electric current in it. Electromagnets are an important part of electrical devices such as hard disks, motors, generators, and MRI machines.
Magnets are one of the most interesting objects we come across in our daily lives. Though they have perplexed humans from the ancient times, our current understanding of the phenomenon of magnetism has rewarded us with countless useful devices that enrich our lives.
The earth’s crust consists of ultra rare metals that offer select advantage in harnessing magnetic power. All the generators harness resistance against a force to create energy generally in the form of a coiled wire. Permanent magnets enable select new motors to create force. This is a new kind of magnetism in which rare earth metals like neodymium is used for creating magnetic force. Permanent magnets motors can power various machines from simple lawnmowers requiring low-horsepower to the industrial-sized power facilities.
The permanent magnets are so called due to their position within a motor system. Current is turned in to mechanical energy by an electrical motor but electrical force has to be continuously strengthened to facilitate the power movement. This kind of resistance is provided by the magnets in exactly the same way they pull metal: when the charge of electricity is compressed into a flow, the magnetic force challenges this flow to produce the force which results in pushing the gears in a motor. These motors use flow and compression to create mechanical energy just like a steam engine which utilizes the power of compressed hot water to create mechanical energy.
What are the benefits of using permanent magnets motors over conventional wire resistors? Both direct as well as alternating current is required by wires for creating mechanical energy. But only a basic charge of alternating current is required by magnets for creating energy. This minimizes the need for additional outlets and energy concerns. Similarly, the need for slip rings is reduced; as a result of this, magnets create less strain on machines which keeps the complete assembly in fixed formation. Due to less waste of energy and less strain, the monitoring and maintenance need for the motors is reduced to a great extent.
Thus the use of a magnetized motor offers various advantages. But there are drawbacks as well. There is consistency of flux in other metals due to the presence of magnet which implies that the air gaps also have a flux when they are vibrating stably with the metals. This can result in breaks and corrosion. The mechanical output is greatly reduced due to higher air gap flux. But the biggest drawback is the cost of the rare earth metals used for replacing magnets. The cost of select rare earth magnets is ten times higher than the cost of iron or lead electromagnet.
Since permanent magnets motors generate power, they are an ideal solution for many power supply and engineering problems. They generate more mechanical force compared to their electrical wire counterpart. Moreover, there is very little maintenance associated with permanent magnets motors than other motors. But its high cost makes it unsuitable to many power suppliers. Moreover, the complications of power control within a magnet make the power supply strong as well as difficult to maintain.
Any metal that has a magnetic field is a magnet. The magnetic field is the area around the magnet that is 'magnetized'. Every single magnet has two poles. Identical poles will resist each other while opposite poles will attract each other. A magnet will attach to any metal that contains iron. However, some magnets are stronger and longer lasting than others. There are two general categories of magnets: temporary magnets and permanent magnets.
Temporary magnets only work when they are located close enough to a magnetic field. These magnets lose their magnetism once this magnetic field is no longer around. A nail, for instance, is a good example of a temporary magnet. Temporary magnets are used inside phones. Some temporary magnets are in fact electro magnets. These magnets are used together with an electrical current. This current causes the temporary magnet to retain its magnetism.
Once the electronic current is gone, the electromagnet will lose its magnetism. A magnet of this nature can be switched on and off by adjusting the source of power. Electromagnets are very useful. These magnets are used in cars, MRI machines and in certain types of industrial equipment. In some cases, electromagnets are more useful then permanent magnets, as one can control how much magnetism electromagnets have by simply adjusting the source of power. Because one can adjust how much magnetism electromagnets have at any given time, these magnets are a lot more versatile than permanent magnets or temporary magnets.
Permanent magnets are ones that do not lose their magnetism. However, permanent magnets may not appear large or imposing. A refrigerator magnet, for instance, is a good example of a permanent magnet. However, some permanent magnets are extremely powerful. Neodymium rare earth magnets are some of the most powerful magnets on earth. They naturally cost more but can also do a lot more. Neodymium magnets are commonly used in cars, computers, credit cards and speakers. A person can also purchase these magnets on their own, but extreme caution should be used when storing them. They can wipe the data of a disc, cell phone or credit card if placed too close by. Neodymium magnets can also cause bodily injury if mishandled. Even a small neodymium magnet can be quite potent and should never be left in the reach of a small child.
Magnets are extremely useful. Without magnets, mankind would not be able to use many modern inventions that are taken for granted today. While there are different types of magnets, no one type is necessarily better than the other. Each type of magnet is useful in its own right. A person who wants to learn more about magnetism will find that experimenting with different types of magnet can be a lot of fun.
