Magnetic Fields

• What is a magnetic field?

  Region around a magnet where force acts
• How can you plot the magnetic field pattern of a magnet?

  Using a compass to draw field lines
• What are the two types of magnets mentioned?

  Permanent and induced magnets
• What is a permanent magnet?

  Always has a magnetic field
• What is an induced magnet?

  Becomes a magnet in a magnetic field
• What are the four types of magnetic materials?

  Iron, steel, cobalt, nickel
• What happens when a magnetic material is placed in a magnetic field?

  It experiences a force of attraction
• How does the strength of a magnetic field change with distance?

  It decreases as distance from the magnet increases
• Where is the magnetic field strongest in a magnet?

  At the poles of the magnet
• How can the direction of a magnetic field be found?

  Using a magnetic compass
• What does a compass needle indicate when held away from magnets?

  It points in the north-south direction
• What causes the Earth's magnetic field?

  The Earth's core is magnetic
• What is the process to plot the magnetic field using a compass?

  1. Place compass near North Pole of magnet
  2. Draw a cross at the North Pole of the compass
  3. Move compass so South Pole is on the cross
  4. Draw another cross at the North Pole of the compass
  5. Repeat until complete magnetic field line is plotted
  6. Connect dots with a line and indicate direction
• What are the characteristics of permanent and induced magnets?

  • Permanent magnets:
  • Always have a magnetic field
  • Induced magnets:
  • Become magnets in a magnetic field
• What are the properties of magnetic materials?

  • Types of magnetic materials:
  • Iron
  • Steel (an alloy of iron)
  • Cobalt
  • Nickel
  • Can be made into permanent or induced magnets
• What is the relationship between distance and magnetic field strength?

  • Magnetic field strength:
  • Strongest at the poles
  • Decreases with distance from the magnet
• How does a compass work in relation to magnetic fields?

  • Contains a small bar magnet
  • Indicates direction of magnetic field
  • Points north-south when away from other magnets