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Magnetism is the force exerted by magnets once they tempt or repel every other. Magnetism is brought about by the activity of electric charges.Every substance is made up of tiny units dubbed atoms. Every atom has actually electrons, corpuscle that lug electric charges. Spinning favor tops, the electrons circle the nucleus, or core, of one atom. Their motion generates an electrical current and causes each electron come act favor a microscope magnet.
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In most substances, equal numbers of electron spin in the contrary directions, which cancels the end their magnetism. The is why products such as towel or record are stated to it is in weakly magnetic. In substances such as iron, cobalt, and nickel, many of the electron spin in the same direction. This provides the atom in this substances strongly magnetic—but they space not however magnets.To come to be magnetized, one more strongly magnetic problem must get in the magnetic ar of an present magnet. The magnetic ar is the area about a magnet that has actually magnetic force. All magnets have actually north and also south poles. Opposite poles space attracted to each other, while the same poles repel each other. As soon as you obstacle a piece of iron follow me a magnet, the north-seeking poles of the atoms in the iron line up in the very same direction. The force generated by the aligned atoms creates a magnetic field. The item of iron has end up being a magnet.Some substances have the right to be magnetized by an electrical current. When electricity runs v a coil that wire, that produces a magnetic field. The field roughly the coil will certainly disappear, however, as soon as the electric existing is turned off. Geomagnetic Poles
The planet is a magnet. Scientists perform not totally understand why, but they think the motion of molten steel in the Earth’s external core generates electric currents. The currents create a magnetic field with invisible lines of pressure flowing in between the Earth’s magnetic poles. The geomagnetic poles space not the same as the North and also South Poles. Earth’s magnetic poles frequently move, early to task far in ~ the Earth’s surface. The shifting areas of the geomagnetic poles are taped in rocks that kind when molten material dubbed magma wells up v the Earth’s crust and also pours out together lava. As lava cools and becomes solid rock, strong magnetic particles within the rock come to be magnetized through the Earth’s magnetic field. The particles line up along the currently of force in the Earth’s field. In this way, rocks lock in a record of the place of the Earth’s geomagnetic poles at the time.
Strangely, the magnetic documents of rocks developed at the very same time seem to point to various locations because that the poles. Follow to the concept of key tectonics, the rocky plates that make up the Earth’s tough shell space constantly moving. Thus, the bowl on which the rocks solidified have actually moved due to the fact that the rocks videotaped the place of the geomagnetic poles. These magnetic records additionally show that the geomagnetic poles have actually reversed—changed right into the opposite sort of pole—hundreds the times because the earth formed.Earth’s magnetic field does not move quickly or reverse often. Therefore, it have the right to be a advantageous tool for helping civilization find their method around. For hundreds of years, human being have offered magnetic compasses come navigate making use of Earth’s magnetic field. The magnetic needle of a compass present up with Earth’s magnetic poles. The north end of a magnet points toward the magnetic north pole. Earth’s magnetic field dominates a an ar called the magnetosphere, which wraps roughly the planet and also its atmosphere. Solar wind, fee particles from the sun, presses the magnetosphere versus the planet on the side encountering the sun and stretches it into a teardrop form on the zero side. The magnetosphere protects the planet from many of the particles, however some leak v it and also become trapped. As soon as particles from the solar wind hit atoms of gas in the top atmosphere around the geomagnetic poles, they create light displays called auroras. These auroras show up over places like Alaska, Canada and also Scandinavia, wherein they are sometimes called “Northern Lights.” The “Southern Lights” deserve to be checked out in Antarctica and brand-new Zealand.
The steel in the sand is magnetic, strongly attracted come the magnet on an atomic level.
Photograph by MaryLou Naccarato, MyShot
Historic DirectionsThe ancient Greeks and also Chinese knew around naturally magnetic stones referred to as "lodestones." these chunks of iron-rich mineral may have actually been magnetized by lightning. The Chinese uncovered that they can make a needle magnetic through stroking it against a lodestone, and also that the needle would point north-south.
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Animal MagnetismSome animals, such as pigeons, bees, and also salmon, deserve to detect the Earth"s magnetic field and also use it to navigate. Scientists aren"t sure just how they do this, but these creatures seem to have magnetic product in their bodies the acts prefer a compass.