Brief Description:

Students build an electromagnet

Grades: 4, 5, 6, 7, 8

Time: 30 mins

Keywords: electromagnetism, magnetism, electricity, magnetic fields, circuits

Necessary Background:

  • Students should understand the basics of circuits and magnetism.
  • Recommended prior activities include Introduction to Magnetism and Act out Electricity/Snap Circuits/Squishy Circuits

Lesson Objectives

  • Students will understand how electricity and magnetism are related
  • Students will build an electromagnet

Materials

  • Nails with an iron core
  • 9V or D batteries
  • Stripped electrical wire (2-3 ft per group)
  • Electrical tape
  • Paper clips (to test magnetism)

Procedure

    1. Review how a circuit works
    2. Review how magnetism works
    3. Discuss similarities between electricity and magnetism.
      1. Opposites attract, likes repel. A magnet has two opposite poles, referred to as north and south. Opposite magnetic poles attract each other, and similar magnetic poles repel each other. Electrical charges (denoted with + and -) behave in the same way.
      2. Both are potential energies.
      3. Electricity and magnetism influence and create each other. Electricity and magnetism are two manifestations of the same fundamental property called electromagnetism. Static electric charges are the source of electric fields while moving charges are the source of magnetic fields. Changing electric fields can alter magnetic fields and vice versa.
    4. This means that by running an electrical current through a metal object, we can create a magnetic field around that object, thus turning it into a magnet. This is called an electromagnet. How are electromagnets different from regular magnets?
      1. An electromagnet can be turned off, but a permanent magnet is always on
    5. In order to make electromagnets, students must wrap the wire around the nail, and then attach the wires to the battery.

 

  • Note: This can create a short circuit and the battery can get fairly warm. If a group’s electromagnet starts to get hot, have them detatch the wires from the battery and let it sit for a few minutes before attempting to build again. Students can use this time to recoil the wire around the nail.

 

  1. Allow students to build and see how many paper clips they can pick up with their electromagnet. What happens when you wrap the wire around the nail more times? Does the magnetic field get stronger or weaker? Test this by seeing how many paper clips the electromagnet can pick up.
    1. The more coils added into the wire, the stronger the magnetic field. Every coil of wire increases the magnetic flux density (strength) of the magnet because each coil adds the magnetic force associated with whatever length of wire was wrapped around the nail.

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