Magnetism

In general, magnetism is understood to be an invisible physical force that acts on matter. In the field of physics, the term summarizes all sub-areas that study magnets and magnetic fields. Accordingly, research on magnetism examines the properties of magnets (such as attraction or repulsion) and the phenomena associated with them. The tesla is used in physics as a unit of measurement for magnetism.

A Brief History of Magnetism

Natural magnets consist of iron, oxygen and iron hydroxide and are formed naturally by volcanism.
Magnetism has been used for profit at least since the invention of the compass - around 1100 AD.
However, the first systematic attempts to determine magnetic force were not carried out before 1269. Pierre de Maricourt studied when magnetic poles attract or repel each other and wrote down his findings. These experiments formed the foundation upon which the magnetism research of later years was built.

First Introduction to Magnetism: The Basics

Much about magnetism is already taught in elementary school. A magnet basically has two poles: The north pole (usually shown in red) and the south pole (usually shown in blue). Outside the magnet, the field lines always run from the north pole to the south pole, in three dimensions. An object must be within this field for the magnet to affect it. Different branches of physics study different types of magnetism, including:

  • Magnetite (manifestation of magnetism in nature
  • Permanent magnets (e.g. rod magnets)
  • Temporary magnets
  • Electromagnets

Iron oxide, samarium, cobalt, and neodymium are commonly used to create permanent magnets. Electromagnets are mainly made up of copper coils.
Nowadays it is possible to artificially produce strong electromagnets. Overheating problems that can arise from magnetism and electricity can be avoided with the help of superconductors.

What are the different types of magnetism?

In order to describe the magnetic properties of individual matter, a distinction is made between three categories:

  • Diamagnetism: The substance has no magnetic effect and is even easily repelled.
  • Paramagnetism: The substance is only weakly attracted.
  • Ferromagnetism: The substance is subjected to a strong magnetic attraction.

Magnets only act on certain, magnetizable raw materials - more precisely on ferromagnetic materials such as:

  • Iron
  • Steel
  • Nickel
  • Cobalt

If an unmagnetized ferromagnet is exposed to an external field and then turns off, the ferromagnet will retain a positive or negative magnetization. In such cases, the magnetism causes a so-called hysteresis (change of effect after change of cause). The negative or positive magnetization that remains during this process is also called remanent magnetism in physics.

Applications of magnetism in everyday life

Nowadays magnetism is omnipresent not only in physics. In everyday life we find magnets in all sorts of places, including:

  • Motor vehicles
  • Hard drives
  • Power converter
  • Construction site equipment

Strong magnetic fields enable the exploration of matter at the atomic level. For example, doctors use magnetic resonance imaging (MRI for short) to examine internal organs and tissue structures. Furthermore, magnetic forces can be converted into electrical forces - and vice versa.
While the position of electrons affects the magnetic property of a material, the movement of electrons, in turn, creates electricity. Therefore, magnetism also plays an important role in the field of electrical engineering. For example, engineers have used magnetic levitation to build high-speed trains such as the Trans rapid Maglev.

As a research area of physics, magnetism also provides explanations for how planets move in space. In principle, our earth is a huge magnet: It has a north and south pole and is surrounded by a natural earth's magnetic field. The earth's magnetic field explains why the needle on a compass always points north.


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