Magnetic fields

• What are the four types of magnetic material

  . Iron

  . Steel (alloy of iron)

  . Cobalt

  . Nickel
• All four magnetic materials can be made into a permenant or induced magnet
• What is a magnetic field

  . A region around a magnet where a force acts on another magnetic field or on a magnetic material
• If we place a magnetic material into a magnetic field, it will ex[erience a force of attraction towards the magnet
• The direction of a magnetic field can be found using a compass
• How to use a compass to plot a magnetic field

  . Place compass near North Pole of bar magnet

  . Draw cross at north pole of compass

  . Move compass so the South Pole of the compass is on the cross and draw another cross on the North Pole of the magnet

  . Continue this until we have plotted a complete magnetic field line

  . Connect all crosses with a line and show direction with an arrow

  . Repeat starting at different points
• Where the lines are closer together in a magnetic field plot is where the field is strongest
• How do we know that the earth has its own magnetic field

  If we hold a compass away from any bar magnets, the needle always points in the north - south direction
• The earths magnetic field is due to the earths core