| Energy
and Change:
|
|
| Facts about magnets |
- Magnets attract materials made from iron, nickel
and cobalt and their alloys such as steel.
- Magnets can push (repel) and pull (attract) at
a distance without actually touching the magnetic object they are acting
on.
- The magnetic force is strongest the nearer the
magnet is to the magnetic object and gets weaker the further the magnet
is moved away.
- The magnetic pushes or pulls a magnetic object
on the other side of non magnetic material such as paper, thin cardboard,
cling wrap, aluminium, glass, wood and some fabrics.
- A free moving magnet can act as a compass.
- A compass is a magnet
- Natural magnetic material such as lodestone and
magnetite, contain large amounts of iron. A story from the Arabian Nights
mentions magnetic rocks. Ancient Chinese and Romans suspended a piece
of magnetite rock by a thread and it lined up in a north-south direction,
which helped them to navigate.
- A magnet is more powerful at the ends than in
the middle.
- One end of a magnet is called the north-seeking
pole and the other end is called the south-seeking pole.
- When two magnets are held together:-
- Like poles repel N
N or S S
(push apart).
- Unlike poles attract N
S (pull together).
- Magnets can lose their magnetic effect if they
are heated or treated roughly, for example; dropped.
- Bar magnets can become demagnetised if stored
incorrectly. They should be stored with a sleeper, often made of wood,
in between the two bar magnets.
- Magnets should not be placed near cassette tapes,
computers, computer discs, plastic or paper magnetic strip cards, television
screens, watches or pace makers.
- Objects such as paper clips and iron nails can
be made magnetic by stroking them with a magnet.
- Magnets have many uses in our lives; catches for
cupboards, fridge magnets, cassettes, bank cards and computer discs
are some common examples.
Links:
Magnets
and magnetism
Magnetic
fields
Magnetic
force and moving charge
The
Earth and magnetism
Making
magnets
|
