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Magnetism is the pressure exerted by magnets when they entice or repel every other. Magnetism is brought about by the movement of electrical charges.Every substance is made up of tiny units called atoms. Each atom has electrons, corpuscle that carry electric charges. Spinning prefer tops, the electron circle the nucleus, or core, of one atom. Their motion generates an electric current and causes every electron come act favor a microscope magnet.
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In most substances, same numbers of electron spin in opposite directions, i m sorry cancels the end their magnetism. That is why materials such as fabric or file are said to it is in weakly magnetic. In building materials such as iron, cobalt, and nickel, many of the electron spin in the very same direction. This renders the atoms in this substances strong magnetic—but they space not yet magnets.To come to be magnetized, an additional strongly magnetic problem must go into the magnetic field of an present magnet. The magnetic ar is the area roughly a magnet that has actually magnetic force. All magnets have north and south poles. The contrary poles are attracted to each other, while the exact same poles repel every other. When you obstacle a piece of iron follow me a magnet, the north-seeking poles the the atom in the iron line up in the same direction. The pressure generated by the aligned atom creates a magnetic field. The item of stole has become a magnet.Some substances have the right to be magnetized by an electrical current. When power runs with a coil of wire, it produces a magnetic field. The field around the coil will certainly disappear, however, as soon as the electric existing is turned off. Geomagnetic Poles
The earth is a magnet. Scientists do not fully understand why, but they think the motion of molten metal in the Earth’s external core generates electric currents. The currents create a magnetic field with invisible currently of pressure 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 often move, due to activity far beneath the Earth’s surface. The shifting areas of the geomagnetic poles are taped in rocks that type when molten material referred to as magma wells up with the Earth’s crust and also pours out as lava. Together lava cools and becomes solid rock, strong magnetic particles in ~ the rock become magnetized by the Earth’s magnetic field. The particles heat up follow me the lines of pressure in the Earth’s field. In this way, rocks lock in a document of the position of the Earth’s geomagnetic poles at that time.
Strangely, the magnetic documents of rocks created at the very same time seem to suggest to different locations because that the poles. Follow to the theory of plate tectonics, the rocky bowl that comprise the Earth’s hard shell room constantly moving. Thus, the plates on i m sorry the rocks solidified have actually moved due to the fact that the rocks taped the place of the geomagnetic poles. This magnetic records also show the the geomagnetic poles have reversed—changed into the opposite kind of pole—hundreds that times due to the fact that the planet formed.Earth’s magnetic ar does not move quickly or turning back often. Therefore, it can be a useful tool because that helping world find their way around. For thousands of years, civilization have used magnetic compasses come navigate using Earth’s magnetic field. The magnetic needle that a compass lines up v Earth’s magnetic poles. The north finish of a magnet points toward the magnetic phibìc pole. Earth’s magnetic ar dominates a region called the magnetosphere, which wraps approximately the planet and its atmosphere. Solar wind, fee particles from the sun, presses the magnetosphere against the earth on the side facing the sun and stretches it right into a teardrop form on the zero side. The magnetosphere protects the earth from most of the particles, yet some leak with it and become trapped. As soon as particles from the solar wind hit atom of gas in the top atmosphere roughly the geomagnetic poles, they develop light displays called auroras. This auroras show up over locations like Alaska, Canada and also Scandinavia, whereby they room sometimes referred to as “Northern Lights.” The “Southern Lights” deserve to be checked out in Antarctica and new Zealand.
The iron in the sand is magnetic, strong attracted come the magnet top top an atomic level.
Photograph by MaryLou Naccarato, MyShot
Historic DirectionsThe ancient Greeks and Chinese knew around naturally magnetic stones called "lodestones." these chunks the iron-rich mineral may have been magnetized through lightning. The Chinese discovered that they can make a needle magnetic by stroking it against a lodestone, and that the needle would allude north-south.
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Animal MagnetismSome animals, such as pigeons, bees, and salmon, can detect the Earth"s magnetic field and also use it to navigate. Scientists aren"t sure exactly how they do this, however these creatures seem to have actually magnetic material in their bodies that acts like a compass.