Magnetism

• Unlike poles attract and like poles repel
• Permanent magnets are made of?

  Iron

  Nickel

  Cobalt

  Steel (contains Iron)
• Permanent magnets are made of permanent magnetic material and produce their own magnetic field all the time
• Induced magnets can only produce a magnetic field when in another external objects magnetic field, when the magnet is taken away it loses its magnetism
• All magnets produce a magnetic field around them. The stronger the magnet, the stronger the magnetic field.
• We can show a magnetic field by drawing:

  The magnetic field lines ALWAYS go from north to south

  A) pole

  B) pole

  C) magnetic field lines

  
• The magnetic field is strongest at the poles of the magnet
• Uniform Magnetic Fields

  When magnetic field lines are the same distance apart and same strength everywhere between the poles, we say that the magnetic field is uniform

  A) N

  B) S

  
• Compasses


  inside a compass is a tiny bat magnet called a needle
• a compasses needle always lines up and is parallel to the magnetic field it is in

  A) the needle of a compass points south of the magnet

  
• a compasses needle always lines up and are parallel to the magnetic field it is in

  
• When not near a magnet, compasses always point in the direction towards the earth's north pole(parallel)because the earth generates its own magnetic field

  (showing the earth's core must be magnetic)
• if you put a magnetic material into a permanent magnet's(bar magnet) field it always attracts
• permanent magnets produce their own magnetic field all the time
• induced magnets (temporary magnets) only produce a magnetic field when in a permanent magnets magnetic field
• if a magnetic material is placed in a permanent magnetic field it becomes an induced magnet
• when removing an induced magnet from a permanent magnetic field the induced magnet will stop producing a magnetic field
• when a current flows through a long straight conductor (wire) a magnetic field is created around it.

  A) current

  B) magnetic field

  
• Right-hand thumb rule


  The direction of the thumb is the direction of the current

  The direction of the curled finger is the direction of the magnetic field

  
• motor effect

  A current-carrying conductor creates a magnetic field, this field can interact with another magnetic field, causing a force that pushes the wire at right angles.

  A) wire carrying current

  B) direction of force

  C) direction of magnetic field

  D) all at 90 degrees

  
• Fleming's Left Hand Rule

  the rule indicates the direction of the current, magnetic field and force to each other(all 90 degrees to each other)

  
• Fleming's Left Hand Rule

  the rule indicates the direction of the current, magnetic field and force to each other(all 90 degrees to each other)

  A) thumb- direction of force

  B) forefinger- magnets magnetic field

  C) middle finger- direction of current in wire

  
• Solenoids 


  a solenoid is a coil of wire which can carry an electric current creating a magnetic field( consists of a wire coiled into a spiral shape)
• Solenoids

  If i place a rod of iron into a solenoid a magnetic field is generated on the rod

  The coils of wire turn the rod into a induced magnet(iron is a magnetic material)

  Solenoids current is strong and uniform

  A) magnetic field lines

  B) solenoid