You and Your Students!
Vicki Cobb, Education World Science Editor
Find the most powerful magnet in your room.
Physical Science, Magnetism
Setting the Scene (Background)
A force is defined as anything that can move matter. One of the most important ideas in physics is that a force can be exerted across a distance without actually touching the object being moved. There are three sources for these forces:
The area through which the force operates is called its field of force.
This activity (activity 17) and the next two weeks' Show-Biz Science entries (activities 18 and 19) will explore the strength of magnet fields, static electricity fields, and gravity.
Students will be able to complete the paper clip activity on their own or in small groups. If you teach young students, the activity in which you use steel wool fragments to reveal a magnetic field might be done as a demonstration; older students will want to do that one on their own.
In this activity, students will create a paper-clip chain: Let one end of a paper clip stick to a magnet. Touch another paper clip to the free end of the first one. Keep going, adding paper clips to the paper-clip chain. How long a chain can you make? Make paper-clip chains for magnets of different sizes. You will be able to make longer chains for some magnets than for others. The magnet with the longest chain has the strongest force field.
Does a magnet's field pass through paper? Put a paper clip on top of a piece of paper with the magnet underneath. Can you move the clip around by moving the magnet? What other materials can the field pass through? Try a plastic container cover, a paper plate, a china dish, or a tabletop.
Make your magnetic field visible. For this activity, students will need extra-fine steel wool, scissors, paper, and a magnet. Put the paper over the magnet. Snip tiny pieces of steel wool evenly over the paper. Watch as they move to show the magnetic field around the magnet underneath. (The lines of force go from one end of a magnet to another.) Have students draw the way the steel wool fragments line up on the paper.
Behind the Scenes
The magnetic field on a permanent magnet is fairly small. The stronger the magnet is, the larger the field of force.
For more information and activities for teaching about fields of force, check out Sources of Forces: Science Fun with Force Fields by Vicki Cobb, illustrated by Steve Haefele (The Millbrook Press, 2002).
Article By Vicki Cobb
Copyright © 2005 Education World