Magnets are fascinating!
In comic books magnetism is turned into an awesome power to possess. (See Magneto on the right...)
We love magnets and gadgets that use them.
Magnetism is linked with the idea of mystical powers - putting things under the 'fluence - moving things by an invisible force - making things float. It is amazing!
Click here to find out about floating frogs (because of the use of magnetism!)
We use magnets for so many things, even 'health aiding' jewelery.
The Magnet - 'naming things' (the scientific terms you need to know)
The end of a magnet that attracts iron objects to it is called the 'pole'. The poles are the places where the magnetic forces are the strongest.
A magnet has two poles - the NORTH pole and the SOUTH pole. If freely suspended it will orientate itself so that the end called the North Pole points north. This is why it is called the North Pole - it seeks out the north.
If you put a magnet near a compass the arrow will point towards the magnet's South Pole. This is because:-
LIKE poles REPEL
OPPOSITE poles ATTRACT
There are three 'magnetic elements': iron, nickel and cobalt. Only these and their alloys (mixtures of metals containing them) will become magnetised if placed in a magnetic field and therefore attracted to a magnet... all other metals will not.
The domain theory
The Domain Theory aims to explain
why metals get magnetised. You need to think of the magnetic elements having little molecular
magnets inside them. These are randomly orientated in an unmagnetized
piece of metal but point in a particular direction in a
Soft magnetic materials (e.g. iron) have domains that easily move into line when the metal is placed in a magnetic field but as soon as the field is removed the domains take on a random pattern again. It returns to being unmagnetized straight away. very little energy is required to magnetise a soft magnetic material. These materials make 'induced magnets'. Induced magnetism always forms so as to cause a force of attraction to the permamnet magnet that is placed near to it..
Hard magnetic materials (e.g. steel) have domains that do not easily move into line when the metal is placed in a magnetic field, a strong field is needed for some time, but then, when the field is removed the domains retain the magnetic pattern. They are used to make 'permanent magnets'. The metal stays magnetic for a long time. A lot of energy is required to magnetise a hard magnetic material. That energy is changed into heat within the material during the magnetism process.
Click here to go to an index page on 'things related to the magnetic'
Click here for a page on 'the compass'
Click here for a page on using plotting compasses and the field line patterns produced.
Click here for making and destroying magnets.
Click here to see the magnetism related topics split into keystages and links to suitable questions set for those levels of understanding.
The questions have worked solutions and hints on good examination technique.
Click here to try the magnetism wordmaze
Click here to read about the link between magnetism and levitation
Now let's take a look at Electromagnetism....