Magnetism. Magnet and magnetic field

Magnetism is a fundamental property of certain materials that allows them to attract or repel other objects. It is a phenomenon related to the interaction of moving electric charges and is closely linked to electromagnetism, an important branch of physics.

Magnets are objects that exhibit magnetic properties. They have two poles, the north pole and the south pole, which have different characteristics and attract each other. When a magnet is brought close to a ferromagnetic material, such as iron or nickel, these materials can temporarily become magnetic and be attracted to the magnet.

The basis of magnetism lies in electrons, negatively charged subatomic particles that orbit around the nucleus of an atom. Moving electrons generate a magnetic field around them. In an atom, electrons pair up and their magnetic fields cancel each other out. However, in certain materials, such as magnets, the electrons do not pair up and their magnetic fields do not cancel, resulting in a net magnetization.

Magnetism is also related to electricity. Electric current in a wire generates a magnetic field around the wire. This principle is used in the construction of electromagnets, where a coil of wire wound around a magnetic core becomes magnetic when current passes through it. Electromagnets are widely used in technological applications, such as electric motors, generators, transformers and data storage devices, such as hard disks.

In addition, magnetism has applications in navigation. Compasses use a magnetic needle that is aligned with the earth’s magnetic field, which allows the north-south direction to be determined.

The study of magnetism is supported by the laws of electromagnetism, formulated by James Clerk Maxwell in the 19th century. These laws describe the interactions between electric and magnetic fields, and have laid the foundation for the development of modern technologies such as electricity, wireless communications and electronics.