Transcript Chapter 6 Lesson 3

Chapter 6
Lesson 3
Magnetism
Magnetism
• Magnetism is the ability of an object to push
or pull on another object that has the
magnetic property.
• Magnets have two poles: north (N) and south
(S).
• Like poles repel one another; different poles
attract.
• If you cut a magnet in half, each half will form
a new magnet with two poles.
Magnetic Field
• Magnetic fields
form around a
magnet.
• The forces
around our
planet create a
Magnetic Field.
Magnetic Field
• If the poles of atoms line up in the same
direction, a permanent magnet is formed.
• The forces from the aligned poles of the atoms
add up and give a magnet its strength.
• The strength aligns into fields or waves.
Magnetic Field
Electromagnet
• Electromagnet is an electric circuit that
produces a magnetic field. The moving
electrons in electricity generate magnetic
fields.
• The simplest electromagnet is a straight wire.
The magnetic field circles around the wire
when electric current is flowing.
• The magnetism from each loop adds up to
make the coil of an electromagnet.
Electromagnet
Electromagnet
• A voice coil operates audio speakers. The
voice coil sits in a permanent magnetic field.
• Current changes in the coil and alters it’s
magnetic field. This causes the forces to the
permanent magnet to move it back and forth.
• The coil’s vibrations make the cone move back
and forth, creating sound waves in the air.
How can magnets produce electricity?
• A generator is a
device that creates
electric current by
spinning an
electric coil
between the poles
of a magnet.
How can magnets produce electricity?
Electric Generator
Magnetic Levitation
• Magnetic levitation is the lifting of an object
by means of magnetic forces.
• Scientists and engineers have designed trains
that use magnetic levitation to travel on a
track.
• By aligning the right type of poles in the track
and in the train, electromagnets push the
train a few centimeters above the track.
Magnetic Levitation
• By switching the
poles back and
forth the
magnetism is able
to move the train
forward.
Magnetic Levitation