| # | Title | Image | Description | Video |
| 1 | Moiré Pattern Transparencies |
Interference and Diffraction
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Pairs of identical transparencies have circular wave patterns of different wavelengths. Place transparencies on the overheard projector. Vary their relative positions to produce different interference patterns. |
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| 2 | Speaker Bar |
Interference of Sound
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A variable function generator drives two speakers which are mounted on the ends of a long bar. Set the frequency to about 3kHz. The speaker bar is on a turntable. Direct the students to plug one ear and listen for the variations in intensity while you slowly turn the turntable. Alternately, have the students move their heads back and forth while plugging one ear (the speakers do not move). Inclusion of a rheostat allows one speaker to be turned off. |
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| 3 | Trombone | Interference of Sound |
A function generator drives a speaker. The sound travels through two tubes which joining together at the horn. One tube is a trombone slide. Change the distance the sound travels in the sliding tube by raising or lowering the slide. The variation in intensity as the slide is moved is quite pronounced at 3kHz. Measure the change in length of the sliding tube (twice the distance moved). |
