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Magnetism is the pressure exerted by magnets when they lure or repel every other. Magnetism is brought about by the activity of electrical charges.Every problem is made up of small units dubbed atoms. Each atom has electrons, particles that bring electric charges. Spinning favor tops, the electron circle the nucleus, or core, of one atom. Their activity generates an electric current and causes every electron to act like a microscope magnet.
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In many substances, equal numbers of electron spin in the contrary directions, which cancels out their magnetism. That is why products such as fabric or document are said to be weakly magnetic. In building materials such together iron, cobalt, and also nickel, most of the electron spin in the very same direction. This makes the atom in these substances strongly magnetic—but they space not yet magnets.To come to be magnetized, an additional strongly magnetic substance must get in the magnetic ar of an existing magnet. The magnetic ar is the area approximately a magnet that has magnetic force. Every magnets have north and south poles. The contrary poles space attracted to every other, if the very same poles repel every other. When you rub a piece of iron along a magnet, the north-seeking poles the the atoms in the iron line up in the exact same direction. The force generated by the aligned atoms creates a magnetic field. The piece of stole has come to be a magnet.Some substances have the right to be magnetized through an electrical current. When electrical power runs through a coil of wire, it produces a magnetic field. The field about the coil will certainly disappear, however, as soon as the electric current is turned off. Geomagnetic Poles
The earth is a magnet. Scientists execute not completely understand why, yet they think the motion of molten steel in the Earth’s outer core generates electric currents. The currents produce a magnetic ar with invisible lines of force flowing between the Earth’s magnetic poles. The geomagnetic poles space not the exact same as the North and South Poles. Earth’s magnetic poles regularly move, due to activity far beneath the Earth’s surface. The shifting areas of the geomagnetic poles are recorded in rocks that type when molten material called magma wells up through the Earth’s crust and also pours out together lava. Together lava cools and also becomes hard rock, strongly magnetic particles within the rock end up being magnetized through the Earth’s magnetic field. The particles line up along the currently of pressure in the Earth’s field. In this way, rocks lock in a document of the place of the Earth’s geomagnetic poles at that time.
Strangely, the magnetic records of rocks created at the very same time it seems ~ to allude to various locations for the poles. According to the concept of bowl tectonics, the rocky plates that make up the Earth’s hard shell room constantly moving. Thus, the bowl on i m sorry the rocks solidified have actually moved since the rocks taped the place of the geomagnetic poles. These magnetic records also show that the geomagnetic poles have actually reversed—changed right into the opposite kind of pole—hundreds the times because the earth formed.Earth’s magnetic field does not move quickly or turning back often. Therefore, it have the right to be a valuable tool for helping people find their method around. For thousands of years, human being have used magnetic compasses come navigate using Earth’s magnetic field. The magnetic needle of a compass currently up through Earth’s magnetic poles. The north finish of a magnet points towards the magnetic north pole. Earth’s magnetic ar dominates a an ar called the magnetosphere, i m sorry wraps approximately the planet and its atmosphere. Solar wind, fee particles from the sun, presses the magnetosphere against the planet on the side facing the sun and stretches it into a teardrop shape on the zero side. The magnetosphere protects the planet from most of the particles, but some leak v it and also become trapped. As soon as particles native the solar wind hit atoms of gas in the top atmosphere approximately the geomagnetic poles, they create light display screens called auroras. This auroras appear over areas like Alaska, Canada and Scandinavia, whereby they room sometimes dubbed “Northern Lights.” The “Southern Lights” deserve to be viewed in Antarctica and brand-new Zealand.
The stole in the sand is magnetic, strong attracted come the magnet on an atom level.
Photograph through MaryLou Naccarato, MyShot
Historic DirectionsThe old Greeks and also Chinese knew around naturally magnetic stones called "lodestones." these chunks the iron-rich minerals may have been magnetized through lightning. The Chinese uncovered that they could make a needle magnetic by stroking it against a lodestone, and that the needle would suggest north-south.
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Animal MagnetismSome animals, such together pigeons, bees, and salmon, have the right to detect the Earth"s magnetic field and use it to navigate. Scientists aren"t sure exactly how they do this, however these creatures it seems ~ to have magnetic product in your bodies the acts prefer a compass.