Electromagnets
There is one special type of magnet that is a little different than all other maenets. This
special magnet is called an electromagnet. Electromagnets are created by wrapping a wire
around a magnet and sending a current through the wire. You already knew that magnets attract
(pull) or repel (push) other magnets and magnetic objects. But did you know that magnets con also
exert their force on other materials in a way that makes these materials magnetic? When a current
of electrical energy is sent through the wrapped wire, it creates a magnetic field at the center of
the magnet. You are probably more familiar with electromagnets than you think!
Many kitchen appliances, such as blenders and vacuums, are electromagnets. These
household electronics need a lot of power to do what they do
they need an electromagnet!
Several things can be done to electromagnets to make them strong enough to power these types
of electronics. Remember that an electromagnet is created by wrapping a wire around a magnet.
The strength of an electromagnet increases as more coils of wire are wrapped around its magnetic
core. The wire cant just be any wire, though, It has to be an insulated conductive wire. This means
that the wire itself is made of a metal that conducts electricity, but the outside of the wire is
wrapped in an insulator (usually plastic). The metal wire allows electricity to pass through it, hut the
plastic wrapping on the outside keeps the electricity inside the wire. Increasing the thickness of the
conductive wire can also increase the strength of the electromagnet.
Changing the wire is one just way to change an electromagnets strength. Another way to
change the strength is to change the other part of the electromagnet: the magnetic core. Some
magnets are naturally stronger than others, so using a stronger magnet for the magnetic core of the
electromagnet will increase its strength. Iron, which is stronger than nickel and some other common
metals, is an example of a strong magnet. Using a stronger magnet in the core of the
electromagnet increases the strength of the electromagnet without increasing its size. Of course,
increasing the size of the magnet at the core will also make the electromagnet stronger.
Electromagnets need a power source to push the electric current through its wires. The
power source is usually either a battery or a generator. Using stronger batteries pushes stronger
currents through faster, which creates a stronger electromagnet. Adding more catteries to the
electromagnet increases the strength of the magnet, too. Batteries are usually used in
electromagnets to power smaller, handheld items. Electromagnets that are used to power larger
things, like blenders and vacuums, use generators as the power source.
The main differences between a magnet and an electromagnet are that magnets are
natural and are permanently magnetic, while electromagnets are man-made and their magnetic
field can be controlled. Magnets never lose their magnetism. Despite being man-made,
electromagnets are very useful because the strength of their magnetic field can be adjusted based
on the amount of energy currents that are sent through the wire. The more energy currents that are
sent through the wire, the stronger the electromagnets magnetic field. Unlike regular magnets, the
magnetic field of on electromagnet con be turned on and off with a switch. If the current is turned
off, the electromagnets magnetic field disappears. See how many things you can find in your
kitch.en at home thai are powered by electromagnets!
FAST FACT: Door bells and computer hard drives ore both powered by electromagnets.
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