4.3.2 Magnetic Lines of Force
NAME:
DATE:
PARTNERS:
Purpose:
To see magnetic lines of force by using iron filings and a variety of magnets.
Materials:
1. Sheets of looseleaf paper
2. Iron filings
3. Bar magnet
4. Flat fridge magnet
5. Horseshoe magnet
6. pencil
Procedure:
1. Place the bar magnet flat on the table
2. Place a piece of paper on top of the magnet
3. Sprinkle iron filings evenly on the paper or the cardboard
4. Tap the paper lightly
5. With a pencil, draw lines along the patterns created by the iron filings
6. Remove the iron filings by pouring them carefully back into the container, and study the pencil lines.
7. Repeat steps 2-6 for a fridge magnet placed under the paper, and with someone holding a horseshoe
magnet upright so its two ends are “ standing” on the paper.
Observations:
1. Examine the traces on the paper, and sketch your results below. Label the poles for the bar &
horseshoe magnets.
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4.3.2 Magnetic Lines of Force
Bar Magnet sketch:
Flat “f ridge” magnet sketch
Horseshoe magnet sketch
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4.3.2 Magnetic Lines of Force
2. The patterns you’ re seeing are actually the magnetic lines of force. What is significant about where
these lines begin and end?
3. Where do the filings seem to stand on end?
4. Indicate on your sketch the location where the iron filings feel equal attraction from both poles. Do the
lines have a particular structure at this location?
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4.3.2 Magnetic Lines of Force
5. Does the strength of the magnet have any effect on the magnetic lines of force?
6. How do the lines of force of the bar magnet differ from that of the horseshoe magnet?
7. Do the magnetic lines of force of the flat “ fridge” magnet indicate at all how fridge magnets are made?
Brainstorm with your group how these might be manufactured.
References:
Lorbeer, George C. Science Activities for Elementary Students, (Toronto: McGraw Hill, 2000), p. 63.
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4.3.2 Magnetic Lines of Force
Summary and Suggestions for the Future:
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1. What were the important concepts of physics/science that you learned from this activity? What else did you
learn?
2. Can you think of alternative hands-on ways in which these concepts could be demonstrated? Can you
suggest any improvements to these activities?
3. What changes would you make to teach these activities in a Grade 7-8 classroom? What difficulties can you
foresee?