A magnet is an object or device that pulls certain metals toward itself. The power of attraction of a magnet usually works on iron, cobalt, nickel, some types of alloys, and some types of steel. In addition, a magnet can also exert either attractive force or repulsive force on another magnet.
There are different kinds of magnets. They also have variable magnetic strengths. A magnet’s strength is usually expressed as its mass divided by the product of its electrical charge and time. The tesla (T) is the standard unit for measuring the magnetic field strength. One tesla is 1 kg per coulomb second. A related unit is the gauss, which is equivalent to 0.0001 tesla.
You can measure the magnet’s field strength using several devices made for the purpose. The most commonly used ones are magnetometers, gaussmeters, and pull-testers. Magnetometers can take measurements in gauss units and other random units. Gaussmeters exclusively measure magnetic strength in terms of gauss units. Pull-testers can quantify the magnet’s pull power in terms of force units such as kilograms or pounds.
Here are some tips to keep in mind if you want to measure how strong a magnet is.
- Have some idea of the magnetic field strength of magnets that are commonly found in nature and in industries. For instance, the Earth itself is a very big magnet. The strength of its magnetic field is about 0.5 gauss. On the other hand, the magnet that you can find in a refrigerator has a stronger power than the Earth itself; a refrigerator magnet usually has about a hundred gauss. Permanent magnets, such as those made of neodymium, are also usually very potent. A small piece of such magnets can have a magnetic strength of about a couple thousand gauss, while an electromagnetic can pack as much as 15,000 gauss.
- Use a cantilever beam magnetometer to measure magnetic strength. Such a device comes in three types. With a capacitive magnetometer, you can measure the force of the magnet’s moment in a field. Capacitive magnetometers can accurately measure strength with an accuracy of up to 10-10 J/T (joules per tesla) within a magnetic field measuring 1/10 T per centimeter. For very small samples, you can measure the magnet’s moment using a piezoresistive magnetometer. This device measures changes that happen to the electrical resistance when your specimen is bent. A third type of magnetometer is the vibrating sample magnetometer, which can measure bigger samples with diameters up to 6 mm and at an accuracy of 10-6 J/T. This device can work up to a maximum magnetic field of 33 T.
- For measuring magnetism on surfaces such as liquids, thin films, and gases, you can use a probing device called the magneto-optical Kerr effect probing device. This instrument can operate on samples emitting magnetic fields up to 20 T and up to a maximum of about 2 cm in diameter.
The strength of the magnet you are examining will have an effect on its
intended use, so it is important that you know how to measure the
magnetic strength appropriately. Since there are various instruments
that you can use, you also need to know which one will be the best to
use according to the magnet type, strength, and the kind of magnetic
field being analyzed.