magnets (GCSE physics)

• which poles attract?

  opposite (N-S, S-N)
• which poles repel?

  like poles (N-N, S-S)
• name 4 magnetic materials

  iron, steel, nickel and cobalt
• what is a permanent magnet?

  they cause a force on other magnets or magnetic materials (e.g. horseshoe magnets)
• what is an induced magnet?

  they only become a magnet when placed in a magnetic field. The magnetism is lost when the magnet is removed from the magnetic field.
• which way do the lines go when drawing a magnetic field?

  north to south
• what is a magnetic field?

  a region where magnetic materials expeience a force
• describe a uniformed magnetic field

  a uniformed magnetic field has the same strength and direction at all points and equal spacing between the lines to show they have equal strength.
• describe on of the practicals to show magnetic field

  First, place a bar magnet under a piece of plain paper

  Then, sprinkle some iron filings on top and tap the paper. Observe the magnetic field lines.
• describe another practical to show the magnetic field lines

  First, place a plotting compass near a magnet on a piece of paper.

  Then, mark the direction the compass is pointing to

  Move the compass to differe positions in the magnetic field, mark the direction each time. Join the points to show the magnetic field.