A magnet is one of the more common magnetic substances in our lives, we've all seen and played with iron absorbing stones, and we've experimented with them in physics class. Magnet is a natural thing, not human, this stone can easily suck up some iron containing material, it feels like magic, and the early mariners found its role, the magnet as a simple compass, used to identify the direction of the sea. In fact, its scientific name is called magnet, its atomic structure is relatively special, the two ends of the magnet is called magnetic, first of all, it itself is magnetic, and the magnet can produce a magnetic field, able to attract ferromagnetic substances. What is a ferromagnetic substance? Iron, for example, when not encountering a magnetic field, the internal ordering of the atoms is relatively chaotic, and the magnetic properties cancel each other out.
When it encounters iron, the internal atoms are neatly arranged under the action of the magnet and are attracted to the magnet. So, can a magnet attract all substances? The answer is no. Copper, for example, because it is an antimagnetic substance, will produce a repulsion when in an environment with a magnetic field.
Aluminum will not be attracted by magnets, it is a paramagnetic substance, almost no magnetic field, although in the encounter with the magnet, will produce a certain magnetic field, but this magnetic field is very weak, less than one ten thousandth of iron, so it will not be attracted by magnets. This can also well explain why you can't use aluminum pots and pans on induction cooktops.
So, magnets can attract ferromagnetic substances like iron, but not paramagnetic and antimagnetic substances like aluminum and copper.
In fact, magnets are utilized quite frequently in life. For example, it has been utilized as a compass, including magnetic therapy, which also utilizes this principle, and has also been applied to magnetic levitation trains. So, the magnet in the traditional industry, medicine, military have played its role. It is very big, and contains the existence of many substances, and each of them will be needed by human beings later.
