Download Magnet facts

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What is a magnet made of, and how does it work?
Magnets that you see every day, like the kind people use on refrigerators, are
usually made of iron. Not all iron is magnetic, though. The difference between
magnetized and non-magnetized iron is in their magnetic domains. These are
regions of atoms that all have the same magnetic polarity (North-South alignment).
You can think of them as mini-magnets. In an unmagnetized piece of iron, the
magnetic domains are all jumbled up and pointing in different directions. That makes
their magnetic fields cancel each other out. But in magnetized iron, the magnetic
domains are all lined up in the same direction, so their fields amplify each other.
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If the earth is magnetic, how come magnets don’t go flying toward the
poles?
Earth’s magnetic field is strong enough to cause a floating magnetized needle to
point north—it’s not nearly strong enough to cause all magnets to go flying through
the air toward the poles!
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Why don't all metals stick to magnets?
Even though all metals are affected by being in the presence of a magnetic field,
some of them respond more dramatically and stick to the magnet. Metals like iron,
nickel, and cobalt become temporarily magnetic. In an unmagnetized piece of iron,
the magnetic domains are all jumbled up and pointing in different directions. That
makes their magnetic fields cancel each other out. But in magnetized iron, the
magnetic domains are all lined up in the same direction, so their fields amplify each
other.
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What are the effects of a magnetic force?
The magnetic force attracts metals like iron, nickel, and cobalt to magnets. If the
magnetic force is strong enough, those metals are pulled toward the magnet. All
metals have arrangements of atoms inside them called magnetic domains. Usually,
the poles of these magnetic domains are jumbled up, but when a metal is acted
upon by a magnetic force, the poles line up and the metal becomes magnetic.
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I took a magnet and put it against the metal face of our dishwasher and
the magnet stuck. Then I turned over the magnet and it stuck to the metal
on that side too! Why didn’t the magnet repel on one of the sides?
The reason that both sides of the magnet are attracted to the metal is that metal has
magnetic properties, but is not a magnet. So when you put the north pole of a
magnet near the metal, the magnetic domains near the magnet line up to make that
part of the dishwasher into a south pole. When you place the south pole of a magnet
near the metal, the part of the metal near the magnet becomes a north pole. In
magnets, opposites attract. That's why the metal on your dishwasher is attracted to
either side of a magnet!
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What is geomagnetism?
Geomagnetism is the branch of science that involves magnetism of the earth. The
magnetism that pulls compass needles toward the magnetic north pole is caused by
currents of energy that flow beneath the surface of the earth, through the earth’s
liquid outer core. Imagine that the earth is like a hard piece of candy with multiple
layers. At different levels beneath the surface, different types of rock can be found.
The magnetized core and the magnetized layers closer to the surface all contribute
to the magnetic field or the 'main field' on the earth's surface.
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What is an electromagnet and how can I make my own?
An electromagnet is a magnet that requires an electric force to work. The
electromagnet was invented by William Sturgeon, a British electrician, in 1825. It’s
easy to make a simple electromagnet. All you need is a nail, some insulated wire,
iron filings or paper clips and a D battery. Ask an adult to help you wrap the
insulated wire around the nail, leaving enough at the top and the bottom to connect
to a D battery. Hold one wire on the positive pole of the battery and one on the
bottom, at the same time. This creates a circuit that electricity can run through. Now
try picking up the iron filings or paper clips! The electric current running through the
wire created a magnetic field that, while small because it was only from a D battery,
was enough to pick up the paper clips or iron filings. To make the electromagnet
stronger, you would wrap the wire more times around the nail. Using a different core
will also make it stronger. The last thing is that you can increase the current that
flows through the wire to make it even stronger!
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What’s the difference between a magnet and an electromagnet?
Well, there are three main differences between magnets and electromagnets. First
of all, electromagnets can be turned off. Because the magnetic field is created by an
electric current running through a wire, the magnetic field will disappear if the current
stops. Secondly, electromagnets can have their poles switched if the current
switches directions. Finally, an electromagnet can produce a stronger magnetic field
if the metal wire around it is coiled.
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How are magnets made?
Magnets can be made in a laboratory, but they also naturally exist on our planet.
Magnetite and lodestone are two naturally-occurring magnets. Steel, iron, nickel,
and cobalt can all be magnetized in a laboratory.
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What are the magnetic poles?
Earth’s two magnetic poles—northern and southern—are locations near the
geographic poles where the earth’s magnetic field points directly downward. The
needle of a compass always points toward the North Magnetic Pole.