Magnetism

• Permanent magnets


  Magnets that produce their own magnetic field
• Induced magnets


  Magnetic materials that turn into a magnet when they're put into a magnetic field
• Permanent and induced magnets


  The force between them is always attractive
• When the magnetic field is taken away, induced magnets quickly lose most or all of their magnetism
• How a moving charge creates a magnetic field

  1. Current flows through a wire

  2. Magnetic field is created around the wire

  3. Field is made up of concentric circles perpendicular to the wire

  4. Changing the direction of the current changes the direction of the magnetic field

  5. The strength of the magnetic field changes with the current and distance from the wire
• Right-hand thumb rule


  Using your right hand, point your thumb in the direction of current and curl your fingers. The direction of your fingers is the direction of the field.