3-D demonstration of concept of a field

3-0 DEMONSTRATION OF CONCEPT OF A FIELD Submitted by: Elbert C. Weaver, Southern Connecticut State College, New Haven, Conn. ;\tailing address: RD 4 , 1 7 Beach Ave., Madison, Conn. 06443 Tested by: Willard D. Houston, Ravenna High School, Ravenna, Ohio PREPARATION

Alnico or other very strong magnet(s), inm filings in a sprinkler container, a sheet of stiff paper, and Krylon clear spray varnish should be assembled for the drmonstrntll~n.

After the varnish has dried, carefully lift the paper off the magnets. The filings project from the paper as from a bewiskered chin, sometimes 2 cm or more above the paper. With patience it ma? be possible to build a chain of filings in space from one pole t,oanother.

DEMONSTRATION

REMARKS

Place a sheet of stiff paper over a magnet or array of magnets. Sprinklc iron filings gently onto the paper, and tap the paper lightly. When the force of magnetism on the filings permits no higher build-up of the filings, spray t,he filings wit,h varnish. A higher build-up may he attninrd by alternately sprirrliling and spraying.

Text-book diagrams show cross sections of fields. By this demonst,ration, various fields are shown to have three dimensions. Patt,erns of magnetic fields (N-N, N S , X I S) may be hung up in the classroom for display. Not,e: A set of magnetic balls can he used for interesting effect,s (available from H. Fishlove & CII.,Chicago, Ill. 60610).