Build a Compass

You will need

  • Fridge magnet
  • Small bowl
  • Water
  • Needle
  • Piece of cork

What to do

  1. Rub the fridge magnet along the needle several times. You always need to move the magnet in the same direction along the needle. This is done to magnetize the needle and turn it into a temporary magnet.
  2. Gently push the needle through the middle of the cork. Be very careful not to sting yourself.
  3. Fill the bowl with water.
  4. Place needle and cork in the water.
  5. If left alone the needle will align in a North-South direction in the water. Just like a compass needle would.
  6. If you wish you can use the fridge magnet to manipulate the needle and move it in the water.


Rubbing the fridge magnet along the needle magnetizes it and turns it into a temporary magnet. Temporary magnets only remain magnetic for a short amount of time. Permanent magnets like the fridge magnet are always magnetic.

When inserted into the cork and floating in water the needle acts like a compass. Earth has a magnetic field where the poles are located at the North and the South pole. Therefore, the needle will move to align in a North-South direction when floating in water.

You can watch this experiment as a video here:


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