Transcript Magnetism - Miss Toole`s Science Class

Drill: 10/26/10
►What
is an electromagnet? Why is
it a useful tool?
Magnetism
Magnets
magnet is any material that attracts iron
or materials that contain iron.
►A
► Magnetic
Force- the force of attraction or
repulsion generated by moving or spinning
electric charges (in the magnet)
Magnetic Field
► The
region around a magnet in which
magnetic forces can act
Magnetic Poles
► One
of two points, such as the end of the
magnet, that have opposing magnetic
qualities.
► Opposites
► North
Attract and Like Poles Repel.
and South
Magnetic Earth
► If
you were to hang a magnet on a string, the
north pole of the magnet would point north.
► This is because the Earth has one big
magnetic field, where geographic north actually
is the Magnetic south pole of the Earth and vise
versa.
Atoms and Domains
► Everything
is made of atoms, in a magnet
groups of atoms are in tiny areas called
domains.
► The
north and south poles of magnets line
up and make a magnetic field.
► This
means that even if you cut a magnet
into pieces, each piece will have a north and
south pole.
Magnetizing
► When
a magnet’s domain move because of
another strong magnetic field, dropping or
temperature it can become de-magnetized.
► Objects
made of cobalt, iron or nickel can
be magnetized by lining up its domains.
Kinds of Magnets
► Ferromagnets-
cobalt.
► Temporary
made of iron, nickel or
Magnets- magnetized objects
► Electromagnets-
made by an electric
current around an iron core.
Electromagnetism
► The
interaction between electricity and
magnetism.
► Solenoid-
a coil of wire that produces a
magnetic field when carrying a current.
► Electromagnets
are made from a solenoid
around an iron core.