How do magnets work? A simple explanation
How do magnets work? It almost seems like magic so in this article, we will try to give you the simple explanation. And if you want to know more on magnetism, feel free to read some of the other FAQ articles, we link to.
We will concentrate on permanent magnets (not electro magnets) in this article. The most common known permanent magnet types are ferrite and neodymium. They work a lot alike regarding magnetism but have some differences - we will get to this at the bottom of the article. So first, we will explain simple magnetism.
What is a magnetic field?
A magnetic field is the force between to magnets or a magnet and a magnetic counterpart (e.g. metal). To make it simple, it is the space in which a magnet works. The further space you create between 2 magnets (or a magnet and a magnetic counterpart), the weaker the magnetic field will be (and thus the magnetic force).
The magnetic field is an invisible force that arises from the movement of electric charges. The magnetic field has two poles: the north (N) and south (S) pole, just like a regular magnet. When a magnetic material (like metal) is brought near a magnet, it can get magnetized and exhibit the magnetic force. This is because the magnetic field of the magnet causes the magnetic material to align with the north and south poles of the magnet (also known as magnetic monopolarity as the magnetic field is only an attracting force). Two permanent magnets, on the other hand, will always react either attracting or repelling towards each other as they keep their poles at all times. The most easy way to explain this is that N against N and S against S creates a repulsive magnetic field, but N against S will attract each other.
Magnetic fields play an important role in many areas of modern technology, such as storing information on computer hard drives and generating electricity in power plants. But also for controling robots when you need them to react through attraction and repulsion.
Why do magnets have two poles?
Two poles, north and south, are present in magnets due to the arrangement of atomic dipoles in the magnet. Atomic dipoles result from the movement of electrons in an atom, which generates a slight magnetic field. When atomic dipoles are aligned in the same direction within a magnet, a greater magnetic field is produced, particularly at the poles. Two magnets' south pole will repel one another, while the north pole will be attracted to it. A magnet's magnetic field can be represented by magnetic field lines that extend from its north pole to its south pole. The magnetic force between two magnets is influenced by their magnetic field's strength and the distance between them. Knowing how magnet poles attract and repel is imprtant for many applications like running motor, power generation, and compasses.
As mentioned before, permanent magnets have two poles: north and south. And if you break a magnet, it will still have 1 north and 1 south pole, due to the alignment of the magnet's atomic dipoles. An atomic dipole is caused by the spinning and orbiting of an atom's electrons, which creates a small magnetic field. In a magnet, the atomic dipoles all point in the same direction, creating a larger magnetic field that is stronger at the poles. If you have a magnet with axial magnetism, the poles are at the ends of the magnet. And if you have a magnet with diametrical magnetism, the poles are on the sides (makes most sence with disc magnets, rod magnets, oblong magnets and cone magnets - not with cube magnets and sphere magnets).
The magnetic field around a magnet can easily be visualized with a flux sheet. But you can also make fun experiments to test the magnetic field. The most common way in physics classes is to place ring magnets with axial magnetism on a pole where you can make a larger magnetic field using repelling poles.
The magnetic force between two magnets is proportional to the strength of their magnetic fields and the distance between them. Understanding the attraction and repulsion between the poles of a magnet is crucial to many applications (not only compasses).
What causes magnetism & How is magnetic force created?
Magnetism is the "property" of certain materials to attract or repel each other. A magnetic force is created by the movement of electric charges in the atoms of magnets. When aligned, these charges create a magnetic field around the magnet. Permanent magnets have a magnetic field that is always present. Most articles state that the magnetic field does not weaken over time but this is not 100% true. If you buy a brand new magnet, it gradually loses its magnetism AFTER 80 years (read more below in the section "Do magnets ever stop working" below).
A more tecnical explanation is that magnetism is caused by the presence of charged particles, such as electrons, within the atoms that make up the material. These electrically charged particles create a magnetic field around the atom, and this magnetic field can be enhanced or reinforced if the atoms are arranged in a particular way, for example in a magnetic material. This alignment of atoms is called magnetization.
There are two main theories that explain how magnetism works: the quantum mechanical theory and the classical electromagnetism theory. Both theories describe different aspects of magnetism and are essential for understanding the properties of a magnet. In essence, a magnet is a giant magnet made up of many smaller magnets, or atoms, all aligned in the same direction. If you want to know more, please visit our FAQ site, as we promised that this article would be "the simple explanation to magnetism".
Where can you find permanent magnets?
We have already given examples throughout the article to explain the various magnetic terms, but if you haven't read all sections above, here is a dedicated section to where you can find permanent magnets.
Permanent magnets can be found in many everyday objects such as refrigerator magnets and speakers. They are also used in larger applications such as motors and generators. The strength of a magnet is measured in Gauss or Tesla. They are made with ferro or neodymium material which can only be found very few places on earth (this is also why you might have come across the term "rare earth magnets").
In summary, permanent magnets are a fundamental part of modern technology, and while there are different types of magnets, each has strengths and limitations that make them suitable for specific applications as mentioned above.
Do magnets ever stop working?
If you buy a brand new magnet, it gradually loses its magnetism AFTER 80 years, if you do handle it with care and do not expose it to extreme conditions such as too much heat or cold (different tolerance for different magnet types). So most people will not experience the loss of magnetism in a magnet. And as if 80 years is not impressive enough, it is only after 100 years that you can really feel the loss of magnetism (after 80 years, you can only measure it with a Gauss meter the first couple of years).
What are the biggest differences between ferrite and neodymium magnets?
Ferrite magnets are made of iron oxide and barium or strontium carbonate. They are brittle and have a lower magnetic field strength compared to neodymium magnets. However, they are more resistant to corrosion and are less expensive. They are commonly used in motors, speakers, hotel hairdryers and as refrigerator magnets - but also for ovens and saunas where it is important that the magnets withstand high temperatures.
Neodymium magnets (also known as the strongest magnets on earth) are made of a combination of neodymium, iron, and boron. They are incredibly strong and have a much higher magnetic field strength compared to ferrite magnets. They are also more expensive and are more prone to corrosion because of the high power in the magnetic field (not only between two neodymium magnets but also towards a magnetic counterpart like metal). They are commonly used in high-performance motors, hard drives and headphones - but also for magnetic locks.