2. What is magnetism?
Magnetism is the force of repulsion and
attraction between two different substances
caused by the motion of charged particles.
3. The Law of Magnetic
Attraction
O Force (push or pull) of
a magnet is the
strongest at it ends,
which are called poles.
O North-seeking- points
to earth’s north pole
O South-seeking-points
to earth’s south pole.
O When the two unlike
poles attract and two
like poles repel- law of
magnetic attraction.
4. Magnetic Field
O Space around the magnetic also acts like a
magnet which is a force referred to as a
magnetic field.
O The direction of the magnetic field is the direction
in which the north pole of a compass needle
points when it is placed in the magnetic field.
O Magnetic fields can be represented by magnetic
field lines which are imaginary lines that indicate
the direction and strength of the magnetic field.
O Magnetic field lines form closed loops and never
cross.
5. Is this a misconception?
O A magnetic field is a pattern of lines that
surround a magnet- Why or Why Not?
6. Force of Magnetism
O Magnetism is the result of the spinning
movement of the electrons in the atom.
O Atoms of nonmagnetic materials- half of
electrons spin in one direction, half in the
opposite direction- cancels the magnetic
effects.
O Atoms of magnetic materials- more electrons
spin in one direction than the other- making
the atom a tiny electromagnet.- atoms group
together (domains) line up in north and south
seeking poles.
O When opposite poles of a magnet are brought
together, the lines of force join up and
magnets pull together.
7. Magnets
O Natural magnet (ex. Lodestone) has many poles.
O Ferromagnetic substances-spontaneous magnetism
exists in the substance even in the absence of a
magnetic field.
O Examples-iron, steel, cobalt, nickel, and a few rare
elements dysprodium and gadolinium can be made
into magnets
O Magnets are attracted to metals that contain ferrous,
mainly iron and steel.
O Artificial magnets can be made from ferromagnetic
substances. Sometimes aluminum when mixed with
nickel and cobalt.
Lodeston
e
9. Permanent Magnets
O Permanent magnets are often
made from steel- iron-carbon
alloy.
O Electrons align themselves
and spin in the same direction
while orbiting their nucleus.
This produces a small
magnetic field. As more
electrons align themselves, the
magnetic field becomes
stronger. In the case of
permanent magnets, electrons
tend to stay aligned, unless
heated temperature and then
cooled.
Misconceptio
n or Reality?
Permanent
magnetics can
be made by
placing them
in a strong
magnetic field
10. Magnets losing their
magnetism
O Dropping or striking
them
O 2. heating them
O 3. placing the north
seeking poles side by
side or on top of each
other. The molecules
will be thrown out of
alignment.
11. Keep magnets strong
O Piece of soft iron across the
poles of a U shape magnet
O Attach magnets to a metal
surface
O Store them in pairs with
opposite ends attracting
separated by nonmagnetic
divider (wood, plastic)
O Disk or ring magnets pairs
with opposite poles together
13. Maglev
O Maglev (magnetic levitation) vehicles are
trains that are lifted, propelled, and guided by
fast-moving magnetic fields. Speeds 248 mph
or more.
O Use linear electric motors built into the
guideway to generate a magnetic field that
attracts the vehicle, allowing the train to move
