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Magnetism is the force exerted by magnets as soon as they entice or repel each other. Magnetism is resulted in by the movement of electric charges.Every substance is comprised of tiny units dubbed atoms. Each atom has actually electrons, pwrite-ups that lug electric charges. Spinning like tops, the electrons circle the nucleus, or core, of an atom. Their activity geneprices an electrical current and causes each electron to act choose a microscopic magnet.
You are watching: 1. explain what it means when we say a substance is magnetic.
In most substances, equal numbers of electrons spin in oppowebsite directions, which cancels out their magnetism. That is why materials such as cloth or paper are sassist to be weakly magnetic. In substances such as iron, cobalt, and nickel, most of the electrons spin in the same direction. This renders the atoms in these substances strongly magnetic—yet they are not yet magnets.To become magnetized, one more strongly magnetic substance need to enter the magnetic area of an existing magnet. The magnetic field is the location about a magnet that has magnetic pressure. All magnets have actually north and also southern poles. Opposite poles are attracted to each various other, while the very same poles repel each other. When you rub a piece of iron alengthy a magnet, the north-seeking poles of the atoms in the iron line up in the same direction. The pressure produced by the aligned atoms creates a magnetic area. The piece of iron has actually end up being a magnet.Some substances deserve to be magnetized by an electric present. When power runs with a coil of wire, it produces a magnetic area. The area roughly the coil will disappear, yet, as soon as the electric present is turned off. Geomagnetic Poles
The Planet is a magnet. Scientists do not completely understand why, but they think the movement of molten steel in the Earth’s outer core generates electrical currents. The currental fees produce a magnetic area through invisible lines of force flowing in between the Earth’s magnetic poles. The geomagnetic poles are not the very same as the North and South Poles. Earth’s magnetic poles frequently move, as a result of activity far beneath the Earth’s surchallenge. The shifting places of the geomagnetic poles are videotaped in rocks that form when molten product referred to as magma wells up through the Earth’s crust and pours out as lava. As lava cools and becomes solid rock, strongly magnetic particles within the rock come to be magnetized by the Earth’s magnetic field. The particles line up along the lines of pressure in the Earth’s field. In this method, rocks lock in a record of the place of the Earth’s geomagnetic poles at that time.
Strangely, the magnetic documents of rocks created at the same time seem to allude to various locations for the poles. According to the theory of plate tectonics, the rocky plates that comprise the Earth’s difficult shell are constantly moving. Therefore, the plates on which the rocks solidified have actually relocated considering that the rocks tape-recorded the place of the geomagnetic poles. These magnetic documents also display that the geomagnetic poles have reversed—adjusted right into the opposite kind of pole—numerous times given that the Planet created.Earth’s magnetic field does not relocate quickly or reverse regularly. Therefore, it can be a helpful tool for helping world find their way about. For hundreds of years, people have used magnetic compasses to navigate making use of Earth’s magnetic field. The magnetic needle of a compass lines up through Earth’s magnetic poles. The north finish of a magnet points toward the magnetic north pole. Earth’s magnetic area dominates a region referred to as the magnetosphere, which wraps around the world and its setting. Solar wind, charged particles from the sunlight, presses the magnetospbelow against the Earth on the side facing the sun and stretches it right into a teardrop form on the shadow side. The magnetospbelow protects the Planet from the majority of of the particles, yet some leak with it and also end up being trapped. When pshort articles from the solar wind hit atoms of gas in the upper setting around the geomagnetic poles, they create light display screens called auroras. These auroras show up over places favor Alaska, Canada and also Scandinausing, wbelow they are periodically called “Northern Lights.” The “Southern Lights” can be checked out in Antarctica and New Zealand.
The iron in the sand is magnetic, strongly attracted to the magnet on an atomic level.
Picture by MaryLou Naccarato, MyShot
Historic DirectionsThe primitive Greeks and also Chinese knew around normally magnetic stones dubbed "lodestones." These chunks of iron-affluent minerals might have been magnetized by lightning. The Chinese found that they might make a needle magnetic by stroking it against a lodestone, and also that the needle would certainly allude north-southern.
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Animal MagnetismSome animals, such as pigeons, bees, and also salmon, can detect the Earth"s magnetic field and usage it to navigate. Scientists aren"t certain just how they perform this, yet these creatures seem to have actually magnetic material in their bodies that acts prefer a compass.