Background Information

A magnetic filed surrounds any magnet. This filed is made up of lines of force that are arranged in a definite pattern. Where the lines of force are closest together, the magnetic force is the strongest. It is possible to trace the pattern of the magnetic lines of force by using a small compass. The compass needle will align itself along the magnetic lines of force.

Materials (per pair)

2 bar magnets butcher paper

small compass pencil

tape

Procedure

1. Place one bar magnet in the center of a large sheet of butcher paper. Trace the position of the magnet. Tape the magnet in place so that it will not shift in position.

2. Place the compass beside one pole of the magnet. Make a pencil dot on the paper at the outward end of the compass needle (the end pointing away from the magnet). Move the compass farther out, crossing over the dot. Move it until the opposite end of the needle is at the dot, as shown in Figure A.

3. Now place another mark at the outward end as in Figure B.

4. Continue to move the compass until it goes off the paper or returns to the magnet. The turning of the needle to new positions will direct your placement of dots. Connect the dots with a smooth line.

5. Repeat this process but start at another point at the end of the magnet. Draw at least five lines of force at each end of the magnet.

6. Repeat this procedure on the other side of your butcher paper but use two magnets near each other and make sure to draw in 5 line of force for each of the four ends.

Questions

1. What do the lines you traced represent?

2. What general description of lines of force can you conclude from the tracings?

3. How can these lines help you understand what part of the magnet attracts objects the most?

4. What happened to the magnetic field when the two magnets were near each other?

Write-up

Standard lab report required per pair.