Lesson Plan #:AELP-EAR002
Author: Alfons N. Bouchier; Los Alamos High School, Los Alamos, NM Date: May 1994
Grade Level(s): 8, 9, 10, 11, 12
- Science/Earth Science
OVERVIEW: The magnetic field around a permanent magnet, like the gravitational field around a massive object, is not only invisible, but hard for students to comprehend. With no concrete experience to draw from, they tend to ignore this basic concept, or at best, memorize facts about it.
This activity shows how to map a magnetic field, and to find how a bar magnet’s field combines with the Earth’s magnetic field to form a complex resultant field.
OBJECTIVES: Students will be able to:
Weak to moderate strength bar magnets correctly labeled, very small compasses (sold as ‘flux path compasses’ ), butcher paper.
ACTIVITIES AND PROCEDURES:
- tape a large square of butcher paper down to their table, large enough that a compass can lose a bar magnet’s effect. Lay a bar magnet on the paper and trace around it. Label N and S.
- lay a small compass on the paper, touching the bar magnet anywhere. Place a dot outside the compass case, in line with the end of the needle away from the magnet. Move the compass in the direction the needle points until it is just beyond the dot you just made. Place a second dot where the needle points now. Continue to move the compass and make dots until you reach another point on the bar magnet or the edge of the paper. Connect the dots with a smooth curve. Repeat for other lines, spread out more or less evenly over the area.
- determine and label a direction for each line. The N-seeking tip of a compass will point to the N pole of the Earth or the S end of a bar magnet. Place arrowheads on each line.
- find and label areas where each of the two fields dominate so much that they appear to be the only factor. Find and label an area where the two fields cancel, and explain their evidence for this canceling.
TYING IT ALL TOGETHER:
These lesson plans are the result of the work of the teachers who have attended the Columbia Education Center’s Summer Workshop. CEC is a consortium of teacher from 14 western states dedicated to improving the quality of education in the rural, western, United States, and particularly the quality of math and science Education. CEC uses Big Sky Telegraph as the hub of their telecommunications network that allows the participating teachers to stay in contact with their trainers and peers that they have met at the Workshops.