Table of Contents

1
Table of Contents

• 2 1E1 How Do Magnets Affect One Another?
• 13 1D1 Which Way is North?
• 25 2A2 How Can You Study a Magnetic Field
• 38 2A3 Transparency
• 41 2B4 The Magnetic Field About Two Magnets
• 51 2B5 The Magnetic Field About Two Magnets
• 55 2E1 Demo Magnetic Fields Moving Charges
• 58 3A1 Demo Magnetic Fields Moving Charges
• 63 3A2 Oersteds Serpendipity

2
How Do Magnets Affect One Another?

• 1 E 1 page 16

3
Do

• 1. Hang a magnet with a string using a paper clip.

4

• Bring N-Pole of non-hanging magnet near N-Pole of
  hanging magnet.
• What happened?

5

• What would happen if the S-Pole of non-hanging
  magnet is brought near the N-Pole of the hanging
  magnet?
• Try it.
• What did you observe?

6

• 4. What would happen if the N-Pole of non-hanging
  magnet is brought near the S-Pole of the hanging
  magnet?
• Try it.
• What did you observe?

7

• 5. Now bring the S-Pole of non-hanging magnet
  near the S-Pole of the hanging magnet?
• Try it.
• What did you observe?

8
Summarize

• What happens when like poles of two magnets are
  brought near each other?
• They repel each other.

9
Summarize

• What happens when unlike poles of two magnets are
  brought near each other?
• They attract each other.

10
Law of Magnetic Poles

• Write a short sentence of this law.

11
Prediction

• How would you use a bar magnet with a N and S
  poles marked to identify a bar magnet that is not
  marked?

12

• Thats all there is folks!

13
Which Way is North?

• 1 D 1 page 13

14
Set Up

• Tape a sheet of paper, labeled with N, S, E, and
  W to the table.
• Make sure the paper is oriented correctly.

15
Set Up

• 2. Support a bar magnet with a string connected
  to a paper clip holding a magnet.

16
Set Up

• Position the magnet so that it hangs directly
  over the center of the paper.
• Make sure that the magnet can swing freely.

17
Do

• 5. Twist the magnet a couple of turns. Release
  it. Note the direction in which the N-Pole of the
  magnet points when it stops swinging.

18
Do

• Repeat step 5.
• Did you get the same result?

19
Do

• Remove the magnet and place a compass in the
  center of the sheet of paper.
• Make sure the magnet is not near the compass.
• In which direction does the compass needle
  point?

20
Do

• Turn the compass a few times.
• Does the needle always point in the same
  direction?

21
Analysis

• 9. How is the compass needle like a freely
  suspended bar magnet?

22
Prediction

• Suppose you have a bar magnet with the N and S
  rubbed off.
• How can you tell which end is the N-Pole and
  which is the S-Pole?

23
Prediction

• 12. Why do you think the poles of a magnet are
  named north and south?

24

• Thats all there is folks!

25
How Can You Study a Magnetic Field?

• 2 A 2 page 63

26
Making A Filing Holder

• Fold the piece of clear plastic in half.
• Using scotch tape, seal two of the three sides.
• Have 1/8 teaspoon of steel shot put into the
  pouch.
• Seal the 3rd side with tape.

27
Do

• Place the magnet on the table.
• 2. Shake the plastic until the spheres are spread
  out.
• 3. Place the plastic with spheres on top of the
  magnet.

28
Do

• Tap the plastic sheet.
• a. What happens to the steel spheres as you tap
  the plastic?
• b. Describe how the steel spheres are scattered
  in the plastic?

29
Do

• Sketch your observations of the steel spheres.
• Be sure to outline the magnet and label the N
  and S end.

30
Explanation

• The pattern is produced by an invisible pattern
  of magnetic force around the magnet.
• The space in which magnetism exerts a force is
  called a magnetic field.

31
Explanation

• The pattern that we see with the steel spheres
  are called lines of force.

32
Do

• Describe the pattern produced by the steel
  spheres.
• Where are the greatest and least concentrations
  of spheres?
• What does this represent?

33
Do

• Place a magnet on top of a piece of paper and
  then outline its position.
• Push a paper clip from several directions
  towards the magnet.
• Mark the spot on the paper where the attraction
  first occurs.

34
Question

• 6. How does the pattern of the spheres correspond
  to the distance at which the paperclip is
  attracted to the magnet?

35
Question

• 7. Why doesnt the magnet need to touch a
  magnetic object to attract it?

36
Question

• 8. How can a magnet attract a paperclip without
  touching it?

37
Conclusion

• Based on your observations, which is the
  strongest part of the magnet?
• Explain.

38
2A3 Magnetic Field Around a Bar Magnet p 69
39

• Thats all there is folks!

40
Which Is the Magnet?

• 1 I 2 page 55

41
The Magnetic Field About Two Magnets

• 2 B 4 page 79

42
Do

• 1. Lay 2 bar magnets on a flat surface 4-cm apart.

43
Do

• 2. Place the plexiglas with steel spheres on top
  of the magnets.

44
Do

• 4. Tap the plastic gently.

45
Do

• 5. Draw the resulting pattern.

46
Prediction

• What do you think will happen if you repeat the
  experiment but with the two magnets farther
  apart?
• Try it and then draw your observations.

47
Prediction

• 7. What do you think will happen if you did the
  same experiment, but this time, place the North
  and South Poles of the two magnets 4-cm apart?

48
Prediction

• 8. Test your prediction.

49
Do

• 9. Draw your observations.

50
Conclusion

• What do you conclude about the pattern made by
  the steel spheres when
• a. when like poles are near each other?
• b. when unlike poles are near each other?

51
The Magnetic Field About Two Magnets - Overhead

• 2 B 5 page 83

52
The Magnetic Field Between Unlike Poles
53
The Magnetic Field Between Like Poles
54

• Thats all there is folks!

55
Demo Magnetic Fields and Moving Charges

• 2 E 1 page 93

56
Do

• Bring a bar magnetic field near an electric beam.

57

• Thats all there is folks!

58
Demo Magnetic Fields and Moving Charges

• 3 A 1 page 100

59
Set Up

• Place the plastic with iron filings on the table.
  
• Connect the ends of a copper wire to the
  terminals of a battery.
• 3. Tap the plastic with your finger.

60
Do

• 4. Observe and record what happens.
• Predict what would happen of the wire is
  disconnected from the battery.
• Disconnect the wire from the battery.

61
Do

• 7. Repeat using paper instead of the steel
  spheres.
• Compare results.

62
Infer

• 8. What can you infer about the relationship
  between electricity and magnetism?

63
Oersteds Serpendipity

• 3 A 2 page 103

64
Information

• In the early 1700s, lightning was observed to
  change the direction of the compass needles.
• Could it be that there was a relation between
  electricity and magnetism?

65
Do

• Lay the current carrying wire on top of a
  compass. Throw switch.
• What do you observe?

(This Oersted did absent-mindedly.)
66
Do

• Move the compass at various position relative to
  the wire and/or move the wire relative to the
  compass.
• What do you observe?

67
Observations

• A current carrying wire will cause a magnet
  needle to turn.
• The magnetic field above the wire and beneath the
  wire are opposite in direction.

68
Conclusion

• A current-carrying wire is encircled by a
  magnetic field
• The magnetic field above the wire and beneath the
  wire are opposite in direction.

69

• Thats all there is folks!