Magnet Basics

by Janet Forsythe

Are you wondering “What is gauss?” or “What is bi-polar?”  If so, I will try to answer a few of your questions.

For starters, what is a magnet anyway? A magnet is basically any material that exerts a magnetic field. Magnets fall into two basic types: permanent magnets and electromagnets. Electromagnets generate magnetic fields using electric currents. Permanent magnets, on the other hand, are materials that generate magnetic fields on their own and never lose their strength. Most magnetic therapy products use permanent magnets.

Magnetic flux density is a measure of the strength of the magnetic field produced by a magnet. The tesla (symbol: T) is the most widely used unit of magnetic flux density.  One tesla is equal to 10,000 gauss. Gauss (symbol: G) is a more convenient unit to use when talking about the kinds of magnets that the average person is used to. To give you an idea of what a gauss is, your typical refrigerator magnet exerts a magnetic field of about 10 gauss. Thus, a magnet of one tesla would be a very strong magnet. Magnetic therapy products tend to use magnets that range from a few hundred gauss to over ten thousand gauss. The magnetic flux density of a magnet is largely a function of what the magnet is made of.

Practically speaking, a great number of materials can be made into magnets. Typical permanent magnets include ceramic magnets, plastic magnets, hematite magnets, and neodymium magnets. The last of these, neodymium magnets (also known as rare earth magnets), exert extremely powerful magnetic fields – so strong, in fact, that a neodymium magnet the size of a penny can sometimes lift hundreds of pounds with the force of its magnetic field!

The size of a magnet also plays a significant role in determining the magnet’s therapeutic strength. The same neodymium magnet that can lift hundreds of pounds with its magnetic field may in fact not even be able to penetrate more than a few inches into the human body due to its small size. It is the combination of magnetic flux density and magnet size that determines the therapeutic strength of a particular magnet.

Finally, there is polarity. Perhaps one of the least understood aspects of magnetic therapy is the role that polarity plays in generating therapeutic effects. All magnets have north and south poles, with the magnet’s north pole pointing to Earth’s North Pole and the magnet’s south pole pointing to Earth’s South Pole. Polarity is the term used to describe the alignment of particles within the magnet.  There are two types of magnets: bipolar magnets and unipolar magnets. Bipolar magnets are those that have both north and south polarity on the same side of the magnet, while unipolar magnets have the north pole on one side and the south pole on the other. One difference between bipolar and unipolar magnets is that unipolar magnets tend to have greater penetration than bipolar ones due to the fact that the polarity is uniform on each side. Any other differences between the two types of magnets are still up for investigation.