| DCS # | DEMONSTRATION | REFERENCE | ABSTRACT |
|---|
| 3C20.00 | Pitch | | |
| 3C20.10 | range of hearing | PIRA 200 | Use an oscillator driving a good audio system to demonstrate the range of hearing. |
| 3C20.10 | range of hearing | 3C20.10 | A set of good speakers is used to test the student's range of hearing. |
| 3C20.10 | range of hearing | Sh-3 | An oscillator driving a good audio system is used to demonstrate the range of hearing. |
| 3C20.11 | range of hearing | S-122 | Use whistles, forks, etc. to establish upper range of hearing or an audio oscillator from 10 to 30,000 Hz. |
| 3C20.15 | Galton whistle | Sg-1 | The Galton whistle can be adjusted to produce an intense sound into the ultrasonic range. |
| 3C20.16 | ultrasonic waves | Sf-4 | A set of steel rods tuned to frequencies up to 30 KHz are struck with a hammer and the sound both heard and displayed on an oscilloscope. |
| 3C20.17 | ultrasonic vibrations of quartz | 19-10.1 | Making an ultrasonic transducer and using it to make a fountain and emulsion. |
| 3C20.20 | zip strips | PIRA 500 | |
| 3C20.25 | bottle scale | PIRA 500 | |
| 3C20.25 | musical bottles | Se-4 | Blow across a set of bottles with water levels adjusted to give a scale. |
| 3C20.30 | see 3C60.30 | ref. | see 3C60.30 |
| 3C20.30 | siren disc | PIRA 1000 | |
| 3C20.30 | siren disc | 3C30.20 | |
| 3C20.30 | siren disc | Sc-1 | An air jet is directed at a rotating disc with holes. |
| 3C20.30 | siren disc | S-120 | Air is blown through concentric rows of regularly spaced holes on a spinning disc. Change of speed of the disc changes frequencies but not intervals. |
| 3C20.30 | siren disc | Disc 10-10 | A disc with concentric ring of equally spaced holes is spun by a motor and a jet of air is blown at each circle of holes. |
| 3C20.40 | Savart's wheel | PIRA 1000 | |
| 3C20.40 | frequency and pitch | AJP 32(2),xiv | A set of gears on a single shaft of a variable speed motor have the ratios of 44-47-49-52-55-59-62-66-70-74-78-83-88. |
| 3C20.40 | musical saw | Sc-2 | A card is held against a dull saw as the speed is varied. |
| 3C20.40 | tooth ratio scale | 19-4.3 | A set of gears with 44-47-49-52-59-62-66-70-74-83-88 teeth are mounted coaxially on a shaft connected to a variable speed motor. Varying the speed shows intervals are determined by frequency ratios rather than absolute pitch. |
| 3C20.40 | Savart wheel | S-121 | Hold a stiff cardboard against the rim of a spinning toothed wheel. Use wheels on the same shaft each with different numbers of teeth. |
| 3C20.40 | Savart's wheels | S-3b | A major chord is produced when a cardboard is held against rotating wheels with tooth ratios of 3:4:5:6. |
| 3C20.40 | gear and card | Disc 10-11 | Hold a card against gears on a common shaft with teeth in ratio of 4:5:6:8. |
| 3C20.41 | saw blade organ | 19-4.4 | Several saw blades are mounted on the same rotating shaft with sound produced by amplifying the output of a coil pickup. A band of switches selects the active blades, allowing chords to be played. |
| 3C20.45 | pitch sort of | S-118 | Many examples of sound of poor quality but with some definite pitch. E.g., a thumbnail on a book cover. |
| 3C20.70 | sound cart | AJP 47(2),199 | All the instrumentation for a physics of sound course is loaded on one mobile cart. |