A Simple Introduction to Magnetism
Magnet toys are surprisingly simple to play but they’re quite fascinating. Children are amazed at how easily they can snap 2 magnets together and they stick like glue. There’s no wonder why these toys are such a hit and playing with magnets is probably the first experience of science for most children.
What is magnetism?
Magnetism is defined as a force attractive and repulsive physical phenomena between objects made of certain materials like nickel, steel and iron. It is produced by the motion of electric charge and the surrounding region around a moving charge consists of both a magnetic field and electric field.
Magnetism was discovered and known in the ancient world. In ancient Greece, people use a natural magnet from the mineral magnetite known as lodestone. Aristotle attributed the first scientific discussion of magnetism to the philosopher Thales of Miletus. The ancient Indian medical text Sushruta Samhita describes using magnets for surgical purposes.
In ancient China, the Chinese use a magnetic instrument in their practice of carefully arranging a room or Feng Shui. They have also written about magnetism in the 4th and 2nd BC and described using a magnetic needle compass to improve navigation accuracy in the 11 century and continued improvements to the lodestone compass was made in the century that followed.
It was not until the 13th century when magnetic compasses were first used for navigation in the West which prompted Frenchman Petrus Perigrinus to conduct the first study of magnetism. In the 15th century, English physician William Gilbert proposed that the Earth is a giant magnet. Hans Christian Ørsted discovered magnetic fields around live wires in 1819 and James Clerk Maxwell published his theory of electromagnetism in 1873 which was incorporated into Albert Einstein's theory of special relativity in 1905.
Facts About Magnets
- Magnets have 2 poles; the north pole and south pole. If you cut a magnet bar in half, you create 2 magnets, each having 1 north pole and 1 south pole.
- The two poles of a magnet attract the opposite poles while repelling like poles. The north pole repels the north pole of other magnets while attracting to the south poles. The south pole repels the south pole of other magnets while attracting to the north poles.
- The Earth is like a giant magnet with a north pole and a south pole.
- Magnetization is the process of converting an unmagnetized piece of magnetic material into a magnet by running a magnet over it.
- Magnets are usually made from iron or steel. Other materials like steel-iron, nickel, cobalt, copper and aluminium are also made into powerful magnets.
- Some organisms can detect and use magnetic fields for many purposes such as navigation. For instance, it has long been believed that birds use the Earth’s magnetic field to find their way home and guide them on long distance flights.
- Magnetometer is an instrument used to measure magnetism in objects and ancient rocks.
- Modern trains use magnets to lift them off the ground to reduce friction.