Magents

• Magnets Produce Magnetic Fields
• Magnets


  • Have two poles - north and south
• Magnetic field


  A region where other magnetic materials experience a force
• Showing a magnetic field

  Draw magnetic field lines
• Magnetic field lines


  Show the direction a force would act on a north pole at that point in the field
• Density of magnetic field lines

  The stronger the magnetic field
• Distance from a magnet

  The weaker the magnetic field
• The magnetic field is strongest at the poles of a magnet
• The magnetic forces are also strongest at the poles of a magnet
• Attractive and repulsive magnetic forces

  Between two magnets
• Two like poles (same) will repel each other
• Two unlike poles will attract each other
• Uniform magnetic field


  • Magnetic field is the same strength everywhere between the poles
• Drawing a uniform magnetic field

  Draw at least three field lines, parallel to each other and all the same distance apart
• Compass needle


  A tiny bar magnet that aligns with the magnetic field it is in
• Using a compass to plot magnetic field lines

  1. Place the compass around the magnet and mark the direction of the needle

  2. Move the compass and repeat, joining the marks to draw the field lines

  3. Make sure to draw arrows from north to south on the field lines
• Compasses point towards the Earth's North Pole because the Earth generates its own magnetic field
• The Earth's North Pole is actually a magnetic south pole
• This shows the Earth's core must be magnetic
• The strength of a magnetic field decreases with distance from the source.