We explain what magnetism is and what is the history of this phenomenon. In addition, its relationship with electricity and its applications.
What is magnetism?
When we talk about magnetism or magnetic energy, we refer to one of the two components of electromagnetic radiation (together with electricity , obviously), which manifests itself through forces of attraction or repulsion between certain types of materials and a field of magnetic energy (magnetic field).
While all substances are affected by magnetism , not all do the same. Some materials, such as certain metals (especially iron, nickel, cobalt and their alloys) are particularly prone to it and therefore constitute magnets. Some of them may be of natural origin and others of artificial origin, for example, as a consequence of the action of electricity on certain materials (electromagnets).
Most magnets are magnetic dipoles: substances with a positive pole and a negative pole, due to the flow of electrons in the coupling of their molecules . Each of these poles exerts a force on the matter that is in its area of action, according to a law that establishes that similar poles repel each other, while opposites attract.
These dipoles can occur on a macroscopic scale (for example, on planet Earth: there is a North pole and a South pole, each exerting a magnetic influence that allows the operation of the compasses) or microscopic (for example, in the orientation of certain organic molecules due to the electric charge of their atoms). And these magnetism forces play an important role among the elemental forces of nature .
There are, in broad strokes, diamagnetic (weakly magnetic), paramagnetic (moderately magnetic) or ferromagnetic (highly magnetic) materials.
History of magnetism
The human being knows the magnetism from early times. Its effects were described in Greek antiquity by Thales of Miletus (625-545 BC) and other similar philosophers, who noticed that certain stones from the city of Magnesia del Meandro (Asia Minor) attracted iron. From there comes the name magnetism .
Somehow the human being managed to understand the Earth’s magnetism early, using it in the manufacture of compasses towards the twelfth century , before the emergence as such of the sciences that would later be devoted to the study of this phenomenon.
The first properly formal treatise on magnetism was written in the 13th century by the Frenchman Peter Peregrinus de Maricourt, a prelude to those of future scientific studies by William Gilbert (1600) and especially Hans Christian Orsted (1820), who discovered that magnetism did not It was limited only to magnets, but had a close link with the electric current .
This opened the door for André-Marie Ampère, Carl Friedrich Gauss, Michael Faraday and others to open the field of electromagnetism, and then James Clerk Maxwell determined it through his famous set of equations.
Electricity and magnetism
The relationship between magnetism and electric current is closely linked, and together they make up electromagnetism , one of the elemental forces of the universe . The manipulation of magnetic fields, for example, through the acceleration of magnets, a usable electric current can be generated, as in fact occurs in some types of generators.
And at the same time, by circulating an electric current through certain types of metals, they can be converted into electromagnets and make them attract certain metals or ferromagnetic materials.
This relationship is based on the atomic nature of the materials, in which the electrons (-) of the furthest orbit of the nucleus of the atom (+) can be torn off or transferred from one molecule to another, thus generating an electric flow (current ), and polarizing the assembly, that is, tilting the electric charge to one side (negative pole) and leaving another with less charge (positive pole).
Magnetism has been used by mankind for a long time. As we said before, the invention of the compass and its use for orientation (marking the fixed direction of the North of the planet) dates back hundreds of years, and was key in the development of navigation and in the exploration of the world.
On the other hand, large magnets are used in the electricity generation industry , in medicine (for example, magnetic resonance examinations), in engineering (motor development, conduction and storage of electric charges, etc.) and especially in electronics .
The computer , for example, depends heavily on the use of magnetism for recording information, combined with the power and knowledge of semiconductors.