Magnetic Field Lines Lab (Thomas Herrera)

5. Procedure:

· Place your magnet at the edge of your table.

A. Form a hook from a paper clip. Touch the hook to the magnet.

B. Take turns with your partner and carefully add paper clips to the hook, one by one.

C. Count the total number of paper clips that you can hang onto the hook before the weight becomes too much for the magnet to hold and the paper clips fall. Write this number of paper clips on your data sheet on the line for zero pieces of tape.

D. Next, cut three squares of masking tape (1 X 1 inch). Stick the three pieces of masking tape on the bottom of your magnet. (See the picture to the right.)

E. Repeat your experiment and see how many paper clips you can hang on the hook. Make sure the hook touches the tape, not the magnet itself. Record your findings on your data sheet.

F. Cut three more squares of tape, add them to the layer already present, and repeat your experiment. Record your findings on your data sheet.

G. Keep adding pieces of tape, three at a time, repeat the experiment.

· Repeat Procedure for the different magnets. (Honors Class)

DATA COLLECTION FILE

6. Student Prior Knowledge:

· Permanent vs Temporary Magnets

· Polarity of magnets

· Magnets have fields Lines

7. Explanation:

• Students will discover how barriers and increased distance can vary the strength of a magnet. The main notion to convey in this lesson is that forces can act from a distance. A magnetic field (the pull of the magnet) will pass through materials like tape with almost no effect. The tape does not block the attraction of the magnet for the paper clip. Rather, each piece of tape removes the paper clip from the surface of the magnet by one more small increment of distance, equal to the thickness of the tape. The tape is just a convenient way to move the clip and the magnet apart bit by bit. The distance between the magnet and the clips, not the tape itself, lessens the attraction of the magnet. We also can describe this in terms of the magnetic field: as you move farther from the magnet’s pole, the field becomes weaker and weaker.

8. Questions and Answers:

· As you added more and more layers of tape, what did you notice about the number of paper clips you were able to add to the hook? ______________________________________________________________________________________________________________________________________________________

· How was the tape causing this, was the masking tape a magnet? ______________________________________________________________________________________________________________________________________________________

· Was the magnetic attraction blocked by the tape, or was it just that the tape added distance between the magnet and the paper clip?________________________________________________________________________________________________________________________________________________________________________________

9. Applications to Everyday Life:

· Shielding to protect electronics

· Junkyard

· spectroscopy

11. Videos: