IOWA 4-9 SCIENCE PROJECT

TEACHER GUIDE for: Magnets 7-Seeing the Magnetic Field Marlene Gaston
MAGNETS.490 Grades 4-9

CONCEPT OBJECTIVE: The students will investigate and observe the lines of force in magnetic fields with a compass and with iron filings.

PROCESS OBJECTIVE: To develop a student's observing, exploring, recording, predicting and inferring skills.

MATERIALS (for each student):
1 copy of Student Activity Worksheet 7 A
1 copy of Student Activity Worksheet 7 B
1 cardboard or styrofoam tray
1 small bar magnet
1 compass
(for each small group of 2-4 students):
Small container of iron filings
(for the whole class):
A collection of a wide variety of different sizes, shapes and kinds of magnets. (Ask students to bring magnets from home also to make a larger collection.)

TEACHER BACKGROUND: A source of iron filings is Delta Education, P.O. Box 3000, Nashua, NH 03061-3000 (1-800-442-5444).

EXPLORATION:
1. Distribute 1 small bar magnet, 1 compass and 1 copy of Student Activity Worksheet 7 A.
2. Teacher's directions to students:
"Lay your small magnet on Student Activity Worksheet 7 A and trace around it. Color (or mark) the poles to correspond with your magnet. Set the compass on the paper in many places in the area around the magnet. Carefully draw a small arrow for the direction the compass needle is pointing each time. When you have many arrows, look for a pattern. More arrows make the job easier." (The arrows will point away from one pole, curve around the sides and point toward the other pole.)
Allow enough time for students to have the area around the magnet covered with arrows.

CONCEPT DEVELOPMENT:
(This activity can be done in small groups or with the whole class.)
1. Ask the class:
"What kind of pattern do your arrows make?"
"Did everyone get the same kind of pattern?" (If inexpensive compasses are used, the pattern may be exactly reversed. Inexpensive compasses are easily remagnetized the opposite way. If inexpensive compasses are used, caution the students to move the compasses around the magnet and not over the top.)
2. Introduce the vocabulary "lines of force."
3. Ask "Where are the lines of force the most organized?" (poles)
"How does this compare with the parts of the magnet that are the strongest?" (the same)
4. Ask the students to make a rule about the magnetic field (area around the magnet where the lines of force are) of a magnet.

APPLICATION AND EVALUATION:
1. Distribute 1 copy of Student Activity Worksheet 7 B, 1 cardboard or styrofoam tray, 1 small bar magnet, and 1 piece of typing paper to each pupil and a small container of iron filings between each group of 2-4 students. Place the collection of various sizes, shapes and kinds of magnets where the students can bring them to their work place quickly and easily.
2. Teacher's directions to students:
"Lay your bar magnet near the center of your tray. Place the sheet of typing paper over the magnet. Lightly sprinkle a few iron filings onto the paper over the magnet. Record by drawing the magnet and a few of the lines of force in the magnetic field. Notice where there are more and where there are fewer lines of force. Use Student Activity Worksheet 7 B to record your observations."
3. Have students compare the pattern formed by iron filings with the pattern formed by the compass needle. (They are the same.)
4. Teacher's directions to students:
"Look at the magnetic fields of as many magnets as you have time. (Stress not letting the iron filings get on the magnets.) Lay two magnets down and look at the magnetic field when there is repulsion. Then try attraction." (If the magnets are too far apart the two fields of force do not interact and if the magnets are too close together, the magnets move and the lines are not visible. Taping the magnets to the tray solves the problem.)
Allow enough time for all students to see the magnetic fields of many different magnets.
5. Provide students a time to share in groups to solve any difference of opinions.

MAGNETISM STUDENT ACTIVITY WORKSHEET 7 A

DIRECTIONS: Place a small bar magnet in the center of this paper and trace around it. Color (or mark) the poles of the tracing to correspond with your magnet. Leave the magnet on the paper and place a compass on the paper at many places in the area around the magnet. Carefully draw a small arrow for the direction the compass needle is pointing each time. Look for a pattern in the small arrows you draw. More arrows make the job easier.

MAGNETISM STUDENT ACTIVITY WORKSHEET 7 B

DIRECTIONS: Divide this paper into sections. Draw the magnet or magnets and a few of the lines of force the iron filings form. Include attraction and repulsion between 2 magnets also. Use a section for each drawing.