Magnets and Electromagnets

Magnetic Fields
1. All magnets have a magnetic field
  1. It exerts an attractive force to magnetic materials.
    1. Iron
    2. Steel
    3. Nickel
    4. Cobalt
2. They have no effect on any materials including metal (apart from the ones mentioned here)
3. There are 2 sides to a magnet - north and south
  1. Like sides repel
  2. Different sides attract
4. Diagrams
  1. Lines are close together whenre the field/ force is strong
  2. The lines of force go from North to South
  3. Lines are far apart where the force is weak
Uses of electromagnets
1. Junk yards
  1. To pick up cars and other heavy metal objects
2. Door bells
3. Electric doors
4. Telephones
5. Loudspeakers
How does electromagnetism work?
1. When a current runs through a coil of wire a magnetic field is produced
  1. This magnetic field is similar to one of a bar magnet
  2. This magnetic field may be strengthened by an iron nail.
    1. Although the magnet will be strong It will lose its magnetism very quickly
Breaking/Changing an electromagnet
1. Breaking Magnet
  1. If you break a magnet you will have two magnets, each with their own north and south poles
    1. They will be weaker
2. You can change a magnetic material into a magnet if it is next to a magnet for too long
  1. This is called induced magnetism
Making an electromagnet stronger
1. wrapping the coil around an iron core
2. adding more turns to the coil
3. increasing the current flowing through the coil.
An electromagnet can be switched off just by flipping a switch, unlike a normal magnet
The magnetic field of an electromagnet can be reversed by turning the battery around

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Magnets and Electromagnets

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