Magnets are very useful tools that we use every day without even realising. Did you know that magnets are present inside the computers we use or TVs we watch? Yes, that’s right! Many appliances we use contain magnets ranging in size, from barely visible specks to gigantic ones.
As you already know, magnets are objects which can attract or repel other magnetic materials or metals like iron and steel. But why does this happen?
Here you will learn more about the fundamental laws of magnetism and the magnetic properties of matter.
Law of magnetism
The most fundamental law of magnetism is that like poles attract and unlike poles repel one another. The strongest attractive forces in a magnetic object are at the two ends, called the north pole and south pole.
Many invisible lines of magnetic force surround the north and south pole of a magnet. Magnetic field lines are a visual tool that is used to represent the magnetic field, an invisible field around an object that exerts a magnetic force. These magnetic lines form a circuit as it travels from the north to south and back to the north. The magnetic force around the north and south poles are equally strong, while at the middle portion between the poles it is weaker.
Thus, under the law of magnetism, when you place two south poles of magnets together, the magnets will repel each other due to the strength of the magnetic force. Conversely, putting one north pole and one south pole in a shared magnetic field will cause both magnets to stick together
The different types of magnets
There are 3 different types of magnets: Temporary, permanent, and electromagnets. They are categorised based on their magnetism.
Temporary magnets become magnetised in the presence of a magnetic field. Some other materials that can function as a temporary magnet are paper clips and nails.
Permanent magnets do not lose their magnetism easily. It is a piece of material that retains its magnetism even when not subjected to any external magnetic fields. Some examples include alnicos and ferrites.
Electromagnets are created by placing a metal core inside a coil of wire that carries electrical current. The energised core forms a magnetic field. When the current is turned off, the magnetic field disappears. Appliances such as TVs and computers use electromagnets.
All matter exhibits magnetic properties when placed in an external magnetic field.
How can you make a temporary magnet?
All objects have many tiny particles called atoms. Each atom has electrons that carry electrical charges. The movement of electrons generate an electric current which gives rise to a magnetic field.
To induce magnetism on an object, a highly magnetic material like iron or steel must enter the magnetic field of an existing magnet. For example, when you stroke a piece of iron along a magnet, the north-seeking poles of the atom arrange themselves in the same direction. A magnetic field is created by the force, generated by the aligned atoms. Therefore, this piece of iron will become a magnet.
Summary
The laws of magnetism affect our daily lives deeply. Many of the appliances we use or activities we do consists of magnets. Learning about the fundamental laws of magnetism can help you see the world in a different light.
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