Download Electromagnet

Electromagnetism
Unit Standards
5.P.5A.1 Use mathematical and computational thinking to describe and predict
the motion of an object (including position, direction, and speed).
5.P.5A.2 Develop and use models to explain how the amount or type of force
(contact and non-contact) affects the motion of an object.
5.P.5A.3 Plan and conduct controlled scientific investigations to test the effects
of balanced and unbalanced forces on the rate and direction of motion
of objects.
5.P.5A.4 Analyze and interpret data to describe how a change of force, a change
of mass, or friction affects the motion of an object.
5.P.5A.5 Design and test possible devices or solutions that reduce the effects of
friction on the motion of an object.
What are electromagnets?
• Electromagnet- an
electric circuit that
produces a magnetic
field.
• The moving electrons in
electricity generate
magnetic fields. When
the current stops the
magnetic field
disappears.
What are electromagnets?
• The simplest electromagnet is a straight wire.
• The magnetic field circles around the wire when
current is flowing.
• When you wrap a wire into a loop, you increase
the strength of the magnetic field.
What are electromagnets?
• Many loops together can make a coil.
• The magnetism from each loop adds up to make the coil a
stronger electromagnet.
• The shape of its magnetic field is like a bar magnet’s.
What are electromagnets?
• Placing a rod of iron in a coil will magnetize
the iron. This adds to the strength of the
electromagnet’s magnetic field. Increasing the
current also strengthens the field.
What are electromagnets?
• An iron rod in an electromagnet’s coil is pulled
toward the center of the coil. If you try to pull
it out, it will spring back. This action is used in
a number of devices, such as doorbells.
What are electromagnets?
• A voice coil
operates audio
speakers. The
voice coil sits in
a permanent
magnetic field.
Current changes
in the coil alter
its magnetic
field.
What are electromagnets?
• This causes the
force of the
permanent magnet
to move it back and
forth.
• The coil is
connected to a cone
of paper or metal.
• The coil’s vibrations
make the cone
move back and
forth, creating
sound waves in the
air.
What are electromagnets?
• If several voice coils were placed in a circle,
changes in electric current would cause them to
rotate back and forth.
• Something very similar happens in electric
motors.
What are electromagnets?
• An axle is attached to many coils which are
between two permanent magnets.
• Forces between the permanent magnets and
the coils acting as electromagnets cause the
coils to rotate.
What are electromagnets?
• Electric motors are used in many devices, from
ceiling fans to cars.