Requirement 3 of 11

Electromagnet

Make a simple electromagnet and use it to demonstrate magnetic attraction and repulsion.

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Checklist

Build a simple electromagnet

Use a battery, insulated wire, and an iron core such as a nail to make an electromagnet, then test what it attracts and how changing direction changes the magnetic poles.

Materials

  • One battery such as a D-cell or AA battery pack.
  • Insulated copper wire with the ends stripped.
  • An iron nail or other iron core.
  • A few small metal objects such as paper clips.
  • Optional: a compass or a second magnet to help show pole direction.

Safety

  • Do not leave the wire connected to the battery for long periods because the wire and battery can get hot.
  • Ask an adult for help if you are stripping wire or using any tools.
  • Disconnect the battery when you are finished testing.

How to build it

  • Wrap the insulated wire around the nail many times in the same direction, leaving enough wire free at both ends to connect to the battery.
  • Make sure the wraps are neat and close together, but do not let the bare wire ends touch each other directly.
  • Touch one wire end to one battery terminal and the other wire end to the other terminal.
  • While the circuit is connected, bring the nail close to paper clips or other small steel objects to show attraction.

How to show attraction and repulsion

  • Use the electromagnet to attract paper clips, staples, or other small magnetic metal objects.
  • Use a compass to show that the electromagnet has poles just like a permanent magnet.
  • Reverse the battery connections and notice that the poles switch directions.
  • If you have a second magnet or another electromagnet, compare matching and opposite poles to talk through repulsion and attraction.

What to observe

  • Wrapping more coils can strengthen the magnet.
  • Electric current creates the magnetic field.
  • Using an iron core such as a nail makes the electromagnet stronger than wire alone.
  • Reversing the current changes which end acts like the north or south pole.

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