Electromagnetism basics

• How can you make an electromagnet?

  1.Tightly coil the insulated copper wire around the nail

  -the more turns you make, the stronger the magnetic field

  2.Using crocodile clips and cables, connect the copper wire to the power source(current)

  3.To test the electromagnet, bring the nail near paper clips and observe how many paper clips it picked up
• How does an electromagnet work?

  -When electric current flows through the wire, it creates a magnetic field around the wire.

  -The field magnetises the core, turning it into a powerful magnet, only while the current flows.(Temporary Magnet)
• How to get a stronger electromagnet?

  -coil the wire around the iron nail more so the field lines are denser

  -increase the current
• The more coiled the wire is, the more denser the field lines, which leads to a stronger electromagnet
• Similarities between permanent magnets and electromagnets

  -both create magnetic fields

  -both have north and south poles
• Differences between permanent magnets and electromagnets

  -Electromagnets can be turned on or off

  -Electromagnets can be made stronger or weaker, permanent magnets always have the same strength
• When a current goes through a conductor(like a wire), it creates a magnetic field around it. This is called an electromagnet.
• When a current goes through a wire, the magnetic field lines go around it in a circular motion(360 degrees)
• What is the right hand grip rule?

  -with your RIGHT HAND, do a thumbs up

  -point your thumb to the direction of electron flow(up/down)

  -the way your fingers curl is the direction of the magnetic field lines(clockwise/anticlockwise)
• How does an electric door lock work?

  1. Most of the time, the spring causes the iron bolt to lock the door
  2. When the current flows through the circuit, the electromagnet makes a magnetic field
  3. The electromagnet attracts the iron bolt, unloading the door.
  4. When the current stops, the spring causes the iron bolt to lock the door again
• How does a doorbell work?

  1. When the current flows through the circuit, the electromagnet makes a magnetic field
  2. The electromagnet attracts the springy arm
  3. The arm hits the gong(completes the circuit), which makes a sound
  4. The electromagnet is turned off and the springy metal arm moves back.