Science Experiment – Magnets

By AG Education | December 20, 2017

Measure the length of a magnetic field

About this experiment

All magnets have a magnetic field – the area around a magnet where its magnetic force affects other objects. Depending on the strength of the magnet, this force may cover large or small distances. In this experiment you will test the magnetic field of different magnets.


  • Plastic or wooden ruler
  • Paperclip
  • Two or more different magnets
  • Notebook
  • Pencil


  1. Place the ruler on a flat surface like a table. Place the paperclip alongside the end of the ruler so that one end of the paperclip is in line with the ruler’s zero mark.
  2. Place one magnet at the other end of the ruler. Hold the ruler in place with one hand and slowly slide the magnet toward the paperclip with your other hand.
  3. Once the paperclip moves and becomes attached to the magnet, stop moving the magnet.
  4. Look at which point the magnet was on the ruler when the paperclip attached. This tells you how far apart the paperclip and magnet were when the magnet became strong enough to attract the paperclip.
  5. Record the distance in your notebook. You might want to try a few times with the same magnet to make sure your measurement is correct.
  6. Repeat steps 1–4 with each of the different magnets.
    Which of your magnets was the strongest? Which one was weakest?

By measuring how far the magnet was from the paperclip when they become attached, you discovered the length of the magnetic field. Stronger magnets can attract magnetic materials from a farther distance than weaker magnets can.