Tools & Materials

• Paper clip electromagnet from Building an Electromagnet
• Small 1.5 Volt Battery
• Magnetic compass
• Sheet of A4 or letter size (8 1/2" x 11") paper
• Metric ruler with millimeters
• Pencil
• Timer that can measure in 20 minute increments. A clock or watch will do if you remember to keep an eye on it.
• Unfolded paper clip with a piece of tape marking one end
• A chart like the one below to record your results
• Permanent magnet such as a refrigerator magnet or a bar magnet

Before you get started, you might want to make sure your compass needle is freely rotating. To do this, hold the permanent magnet several inches directly above the north end of the compass. Slowly move the permanent magnet in a circle above the compass. The needle of the compass should freely move around in a circle without getting stuck. Once you have tested the compass, remove the permanent magnet from the experiment area.

What to do:

1. Place the compass on a flat surface.
2. Wait until the compass needle stops moving around. The compass in now pointing towards magnetic north.
3. Turn the base of the compass slowly (the needle shouldn't move) so that the north marking on the compass is directly beneath the north arm of the compass needle.
4. Gently pick up the compass and place the piece of paper under it.
5. Set the compass down at the bottom edge of the paper so that the needle points toward the top of the paper.
6. Draw a line across the paper 1 to 2 cm above the compass, parallel with the bottom edge of the paper. See the diagram at the right.
7. Tape the paper into position. Do not move the compass from this point on. You may even want to tape the compass down.
8. Make a tick mark on the line indicating where the compass needle is pointing. Label this point N for north.
9. Connect the paper clip electromagnet to the battery for 10 seconds. The time could be a bit more or less, but has to be the same for each paper clip you magnetize. Warning: If the wire gets hot to the touch at any point, immediately disconnect the wire from the battery!
10. Slide the paper clip out of its wire covering. Do not uncoil the wire as you will be sliding other paper clips into the coil to magnetize them.
11. Hold the paper clip on the westernmost edge of the paper so that it is pointing straight up out of the paper.
12. Slowly move the paper clip toward the east along the line you drew on the paper. As the paper clip gets closer to the compass, you will notice that the compass needle should move towards the paper clip—it begins pointing towards the west. If the needle is repelled to the east, flip the paper clip over and try again.
13. Make a tick-mark on the line indicating the position of the paper clip when the compass needle is pointing to NNW—halfway between N and NW . Label this point 0 for 0 minutes, the starting time of the experiment.
14. Set the timer for 20 minutes and start it.
15. Measure the distance between the 0 point and the N point to the closest millimeter. Record this distance in the data table under the column Distance From North Marking.
16. Place the paper clip in an isolated location away from any magnets until needed for the next data point.
17. Make sure the compass needle has realigned with magnetic north. You may need to tap the compass several times to make this happen.
18. Repeat steps 11 through 17 every 20 minutes for the next 100 minutes. Label each mark with the elapsed time since the 0 data point.

After you've tried this, take a look at our results.