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Chapter 16 – Magnets
SPI 0807.12.1 - Recognize that electricity can be produced using a
magnet and wire coil.
SPI 0807.12.2 - Describe the basic principles of an electromagnet.
SPI 0807.12.3 - Distinguish among the Earth’s magnetic field, a
magnet, and the fields that surround a magnet and an
electromagnet.
Section 1: Properties
 _________ __________ are points on a magnet that have
____________ magnetic qualities.
 The pole of a magnet that points to the north is called the
magnet’s ____________ _______. The opposite end of the
magnet, called the _________ ________, points to the
south.
 When you bring two magnets close together, the magnets
each exert a magnetic __________ on the other. These
magnetic forces result from spinning electric charges in the
magnets. The force can either ____ the magnets apart of
____ them together.
 If you hold the _______ poles of two magnets close
together, the magnetic force will ______ the magnets part.
The same is true if you hold the south poles close together.
 If you hold the ________ pole of one magnet close to the
________ pole of another magnet, the magnetic force will
______ the magnets together.
 A ___________ _________ exists in the region around a
magnet in which magnetic forces can act.
Why are some materials magnetic and some not?
 In materials such as iron, nickel, and cobalt, groups of
atoms are in tiny areas called ____________. The north
and south poles of the atoms in a domain line up and make
a _________ magnetic field.
 If the domains in an object are ______________ arranged,
the magnetic fields of the individual domains ___________
each other out, and the object has ____ magnetic
properties.
 If most of the domains in the object are __________, the
magnetic fields of the individual domains ____________ to
make the __________ object magnetic.
 Losing Alignment - When domains move, the magnet is
_______________________, or loses its magnetic properties.
 Making Magnets - You can make a magnet from
demagnetized material if you _____ ____ its domains with
another magnet.
 When you ___ a magnet in half, you end up with __ magnets.
Name four kinds of magnets:
 Some magnets, called __________________________, are
made of iron, nickel, cobalt, or mixtures of those metals.
 Another kind of magnet is the ________________________.
This is a magnet made by an electric current.
 _________________ magnets are made from materials that
are easy to magnetize. But they tend to lose their
magnetization easily.
 _______________ magnets are difficult to magnetize, but tend
to keep their magnetic properties longer.
Name 2 examples of the effect of Earth’s magnetic field.
 The Earth behaves as if it has a ________ magnet running
through its center.
 The point of a ___________ needle is attracted to the south
pole of a magnet. Opposite poles of magnets attract each
other.
 A compass needle points north because the ____________
________ of Earth that is closest to the geographic North Pole
is a magnetic south pole.
 Scientists think that the Earth’s magnetic field is made by the
movement of electric charges in the Earth’s ________.
 Earth’s magnetic field plays a part in making __________. An
aurora is formed when _____________ particles from the sun
hit oxygen and nitrogen atoms in the air.
Section 2:
 _______________________—the interaction between
electricity and magnetism.
Solenoids and electromagnets.
 A _____________ is a coil of wire that produces a
magnetic field when carrying an electric current.
 An electromagnet is made up of a solenoid
______________ around an iron core.
 Electromagnets are very useful because they can be turned
_____ and _______ as needed. The solenoid has a field
only when there is _________ current in it.
Section 3:
 Michael Faraday conducted an experiment trying to get the
magnetic field of the electromagnet to make an electric
current in a ____________ wire.
 Faraday realized that electric current in the
_______________ wire was made only when the magnetic
field was __________. The process by which an electric
current is made by changing a magnetic field is called
electromagnetic _________________.
 The electric current produced by the generator changes
direction each time the coil makes a ______ turn. Because
the electric current changes direction, it is an
__________________ current.
 The energy that generators convert into electrical energy
comes from different sources such as ___________ fuels
and _______________energy.
 A ______________ increases or decreases the voltage of
alternating current.
 The number of ___________ in the primary and secondary
coils of a transformer determines whether it increases or
decreases the voltage.
 The electric current that brings electrical energy to your home
is usually transformed _____________ times.