A magnet is an ore that has the property of attracting pieces of iron. This ore was given the name of magnetite, as it is found in a region called Magnesia, located in present-day Turkey.
Magnets have two poles that are called the north pole and the south pole, if we have two magnets close together, we observe that poles with the same name if repel and that poles with different names attract, that is: north pole repels north pole, south pole repels south pole, and north pole and south pole each other attract. See below:
Representation of the interaction between magnetic poles
A given magnet creates in the space around it a magnetic field that we can represent by the lines of magnetic induction, these lines of induction cross from one pole to the other of the magnet. For this reason, even if a magnet is split in half, separating the poles: north and south, it will always reorganize itself so as to form two poles. In other words, we can say that there is no magnetic monopole. If we take small compasses and put them on the magnetic induction lines, the compass needle will always point to it. direction of the magnetic induction vector B, and the north of the needle in the same direction as B, that is, B will be pointing to the south pole of the magnet. Thus, we can say that at each point around the magnet, vector B moves away from the north pole and towards the south pole. In the region of the poles, we see that the magnetic induction lines are closer to each other, so we consider that near the poles the magnetic field is more intense.
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Mind Map: Electromagnetism
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It is possible to visualize magnetic induction lines by scattering iron filings around a magnet. The lines formed by the filings represent the lines of magnetic induction.
Look at the figure below:
Representation of induction lines using iron filings
Earth's magnetic field
Our planet behaves like a gigantic magnet. As such, it creates a magnetic field around it. When we look at a compass, we see that the north pole of the compass needle is oriented toward geographic north. As poles of different names attract, we conclude that the north pole of the compass needle is being attracted by the south pole of the Earth. So the magnetic south pole coincides with the geographic north pole and the magnetic north pole coincides with the geographic south pole.
The Earth's magnetic poles have a small inclination in relation to its axis of rotation, this inclination is approximately 11°. Scientists believe this magnetic property is due to the circular motion of electrical currents in the planet's cast iron core. Research shows that the positions of the magnetic poles change over the years, even inverting their polarity, the north and south poles changing their position.
By Paulo Soares da Silva
Graduated in Physics
Mind Map by Rafael Helerbrock
Graduated in Physics
Would you like to reference this text in a school or academic work? Look:
SILVA, Paulo Soares da. "Magnetism"; Brazil School. Available in: https://brasilescola.uol.com.br/fisica/magnetismo.htm. Accessed on June 27, 2021.
