A manual of experiments and projects in physics

Preface

The distinction between this manual and the large number of manuals already published is that it is written to be used when there is perfect correlation between laboratory work and classroom discus¬ sion; when, if desired, the laboratory work precedes the lecture-room presentation. It is written not as a laboratory text, but to accom¬ pany a text and each experiment presupposes that the student is familiar with the content of some definite assignment.

The author has for many years assigned the topic and the next day sent the student to the laboratory to test for himself the subject of his lesson before his interest and enthusiasm was cooled by class¬ room demonstration and discussion.

The nature of the experiment and the apparatus has been modi¬ fied so that the great majority of students are able to complete the experiment and have their work accepted in one period of fifty minutes.

For the exceptional student who finishes his experiment early in the period, there is an optional part, which is a continuation of some phase of the experiment or a problem applying the principle involved.

When the laboratory work is to correlate perfectly with the class¬ room discussion and become an integral part of the teaching method, it is necessary that all students work on the same experiment. For best results it is desirable that they work individually on the large majority of experiments. The apparatus required for the experi¬ ments in Part I is comparatively inexpensive, and the consequent cost for sets of twenty-four in nearly all experiments is not pro¬ hibitive in the average school. A complete list of the apparatus needed for each experiment is given at the back of the manual.

Mechanics, Sound, and Light are arranged for the first semester and Heat and Electricity for the second semester. This sequence of subjects is best if the projects in Part II are to be considered in a group. However no experiment or group of experiments is based on knowledge obtained in some previous experiment, consequently they may be performed in any desired order.

There are many desirable experiments or tests where the appara¬ tus is of such a nature and cost that sets are impossible. Twenty-one such experiments or projects are given in Part II. These projects

iii are of a practical nature, the principles of physics applied to practi¬ cal problems.

The author’s method has been to set up the apparatus for the projects in Part II some five or six weeks before the close of the semester. They serve as a laboratory review of the semester’s work. Here the students work in groups of two, or individually if they wish, and perform as many as possible, making their own selections.

Part I. Experiments Number Page

1. English and Metric Units . 2

2. Volume of Cylinder — Vernier Caliper. 4

3. Volume of Sphere—Micrometer Screw. 6

4. Density in English Units. 8

5. Density in Metric Units. 10

6. Levers and Moments. 12

7. Parallel Forces. 14

8. Center of Gravity. 16

9. Pulleys . 18

10. Inclined Plane. 20

11. Screw — Automobile Jack. 22

12. Horsepower — Prony Brake. 24

13. Coefficient of Friction. 26

14. Efficiency of Machine. 28

15. Archimedes’ Principle. 30

16. Specific Gravity. 32

17. Open Manometer — Gas Pressure. 34

18. Closed Manometer — Lung Pressure. 36

19. Hooke’s Law. 38

20. Tensile Strength . 40

21. Composition of Forces. 42

22. Simple Crane. 44

23. Resolution of Forces. 46

24. Accelerated Motion. 48

25. Laws of the Pendulum. 50

26. Acceleration of Gravity. 52

27. Second Law of Motion. 54

28. Wave Length by Resonance. 56

29. Wave Length by Interference. 58

30. Laws of Vibrating Strings. 60

31. Plane Mirrors. 62

32. Convex Cylindrical Mirror. 64

33. Concave Cylindrical Mirror. 66 v

NUMBER PAGE

34. Spherical Mirrors. 68

35. Index of Refraction of Water. 70

36. Speed of Light in Glass. 72

37. Refraction by Prisms. 74

38. Lenses — Focal Length and Images. 76

39. Coefficient of Linear Expansion. 78

40. Specific Heat of Metals. 80

41. Temperature of Gas Flame. 82

42. Latent Heat of Snow. 84

43. Latent Heat of Steam. 86

44. Efficiency of Gas Heating. 88

45. Magnetic Fields. 90

46. Electromotive Forces. 92

47. Resistance — Ammeter-voltmeter. 94

48. Resistance — Wheatstone Bridge. 96

49. Series Circuits. 98

50. Parallel Circuits.100

51. Battery Connections.102

52. Terminal Voltage and Resistance of Cell.104

53. Electromagnetism.106

54. Electric Bell.108

55. Telegraphy.109

56. Electrolysis. 110

57. Efficiency of Electric Heating.112

58. Electromagnetic Induction. 114

59. Study of Dynamos.116

60. Study of Electric Motors.118

61. Horsepower of Automobiles.120

62. Power and Torque Curves.122

63. Automobile Road Thrust.124

64. Automobile Electric Circuits.126