Download Magnets

Bell Work 2/18/16
Bell Work 2/18/16
White Board Word Splash
How are magnets related to your everyday life?
What is the relationship between magnets and electronics
(devices).
Describe things that are attracted to magnets? What would
happen if you dipped a bar magnet into a box of paper
clips?
Predict ways magnets could change the way we travel from
place to place.
Cool Stuff
Cling Climb
Maglev Train 2000mph
Video
HYPERLOOP
Student Objectives
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
TOC: Magnets
Video
Magnetic Poles are points on a magnet
that have opposite magnetic qualities.
The pole of a magnet that points to the
north is called the magnet’s north pole.
The opposite end of the magnet, called the
south pole, points to the south.
When you bring two magnets close together,
the magnets each exert a magnetic force on
the other. These magnetic forces result from
spinning electric charges in the magnets.
The force can either push the magnets apart
of pull them together.
If you hold the north poles of two
magnets close together, the
magnetic force will push the
magnets part. The same is true if
you hold the south poles close
together.
If you hold the north pole of one
magnet close to the south pole of
another magnet, the magnetic
force will pull the magnets
together.
A magnetic field 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
domains. The north and south poles of the
atoms in a domain line up and make a strong
magnetic field.
If the domains in an object are randomly
arranged, the magnetic fields of the
individual domains cancel each other out,
and the object has no magnetic properties.
If most of the domains in the object are aligned, the
magnetic fields of the individual domains combine to
make the whole object magnetic.
Losing Alignment - When domains move, the magnet
is demagnetized, or loses its magnetic properties.
Making Magnets - You can make a magnet from
demagnetized material if you line up its domains
with another magnet.
When you cut a magnet in half, you end up with two
magnets.
Name four kinds of magnets
Some magnets, called ferromagnets, are
made of iron, nickel, cobalt, or mixtures of
those metals.
Another kind of magnet is the electromagnet.
This is a magnet made by an electric current.
Temporary magnets are made from materials
that are easy to magnetize. But they tend to
lose their magnetization easily.
Permanent magnets are difficult to
magnetize, but tend to keep their magnetic
properties longer.
Name two examples of the effect of Earth’s
magnetic field.
The Earth behaves as if it has a bar magnet
running through its center.
The point of a compass needle is attracted to
the south pole of a magnet. Opposite poles
of magnets attract each other.
A compass needle points north because the
magnetic pole 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 core.
Earth’s magnetic field plays a part in making
auroras. An aurora is formed when charged
particles from the sun hit oxygen and
nitrogen atoms in the air.
Facts About Electricity
Electric currents produce a magnetic field
The direction of the field depends on the direction of
the current
It is a force caused by electric charge
The two positive charges repel each other, as do the
negatives
Travels at the speed of light (186,000 mph)
Section 2:
Electromagnetism—the interaction between
electricity and magnetism.
Solenoids and electromagnets.
A solenoid is a coil of wire that produces a magnetic
field when carrying an electric current.
An electromagnet is made up of a solenoid wrapped
around an iron core.
Electromagnets are very useful because they can be
turned on and off as needed. The solenoid has a
field only when there is electric current in it.
Group Activity:
Move Around The Room
Independent Work:
• Complete Venn Diagram on Magnetism and
Electricity
Exit Ticket
Exit Ticket
Section 3:
Michael Faraday conducted an experiment trying to
get the magnetic field of the electromagnet to make
an electric current in a second wire.
Faraday realized that electric current in the second
wire was made only when the magnetic field was
changing. The process by which an electric current
is made by changing a magnetic field is called
electromagnetic induction.
The electric current produced by the generator
changes direction each time the coil makes a half
turn. Because the electric current changes direction,
it is an alternating current.
The energy that generators convert into
electrical energy comes from different
sources such as fossil fuels and nuclear
energy.
A transformer increases or decreases the
voltage of alternating current.
The number of loops 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
three times.