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3B SCIENTIFIC

PHYSICS

Acoustics Kit U8440012

Instruction sheet

05/09 ELWE/ALF

1. Description

This set of apparatus makes it possible to impart an

extensive and well-rounded overview on the topic

of acoustics. The set can be used for conducting

numerous experiments.

Sample experiments:

1. String tones

2. Pure acoustic tones

3. Vibrating air columns

4. Open air column

5. Whistle

6. Vibrating rods

7. Infrasound

8. Ultrasound

9. Tuning fork with plotter pen

10. Progressive waves

11. Doppler effect

12. Chladni figures

13. Chimes

14. Standing waves

15. Overtones

16. Measurement of wavelength

17. Soundboard

18. Resonator box

19. Spherical cavity resonator

20. Stringed instruments and the laws they obey

21. Scales on stringed instruments

22. Measurement of string tension

23. Relation between pitch and string tension

24. Wind instruments and the laws they obey

25. C major scale and its intervals

26. Harmony and dissonance

27. G major triad

28. Four-part G major chord

29. Major scales in an arbitrary key

30. Introduction of semitones

The set is supplied in a plastic tray with a foam

insert that facilitates safe storage of the individual

components.

Summary of content (8 pages)

PAGE 1
3B SCIENTIFIC® PHYSICS Acoustics Kit U8440012 Instruction sheet 05/09 ELWE/ALF 16. Measurement of wavelength 17. Soundboard 18. Resonator box 19. Spherical cavity resonator 20. Stringed instruments and the laws they obey 21. Scales on stringed instruments 22. Measurement of string tension 23. Relation between pitch and string tension 24. Wind instruments and the laws they obey 25. C major scale and its intervals 26. Harmony and dissonance 27. G major triad 28. Four-part G major chord 29.
PAGE 2
17 18 19 20 21 22 23 24 25 26 27 28 2. Contents 1 Trays with foam inserts for acoustics kit 2 Monochord 3 Bridge for monochord 4 Metallophone 5 Chladni plate 6 Tuning fork, 1700 Hz 7 Tuning fork, 440 Hz 8 Tuning fork with plotter pen, 21 Hz 9 Spring balance 10 Retaining clip 11 Table clamp 12 Helmholtz resonators 70 mm dia. 52 mm dia.v 40 mm dia. 34 mm dia.
PAGE 3
. Technical data Dimensions: Weight: Wavekength = 530 x 375 x 155 mm3 approx. 4.5 kg approx. Speedofpropagation Frequency 34000 ⋅ cm / s = 77.2 ⋅ cm 440 ⋅ Exciting freq / s the wavelength of the tone produced is 77.2 cm. One quarter of this wavelength is therefore 19.3 cm. The distance between the plunger and the opening at the end of the tube is 19.3 cm when resonance occurs. 4. Sample experiments 1. String tones • Pluck the monochord string hard when it is moderately taut.
PAGE 4
From the centre of motion (the hand), a wave is produced which runs along the wire with an increasing velocity, gets reflected at the fixed end and returns to the point of origin. Reasons: every solid, liquid and gas produces vibrations when disturbed suddenly. These vibrations spread through a medium with a definite propagation velocity. 7. Infrasound • Without the plotter pen attached, make the tuning fork (21 Hz) vibrate by pressing its prongs together and suddenly releasing them.
PAGE 5
Apart from the fundamental tone, all the possible odd overtones or harmonics from the harmonic series are produced at varying degrees of intensity. The fact that every musical instrument has a very characteristic timbre can be attributed solely to the presence of individual harmonics of this kind appearing to a greater or lesser degree. 13. Chimes • Secure the bell dome to the bench with its open end facing upwards using the table clamp and plastic block.
PAGE 6
the string to the total length of the string (40 cm). 18. Resonator box • Strike the A tuning fork (440 Hz) nice and hard and place its stem on the resonator box of the monochord. There is a significant amplification of the tone. Reasons: as explained in experiment 17. 19. Spherical cavity resonator One by one, bring the narrow tip of each of the Helmholtz resonators close to your ear. You hear a tone which gets deeper as the diameter of the resonator becomes greater.
PAGE 7
(To obtain a physically correct frequency, the fundamental frequencies printed on the pipe need to be multiplied by 33). It is also possible for the tuning of the reed pipe and metallophone to differ audibly due to manufacturing processes. fold, four-fold, etc. As measured earlier, 1/4 of 5.5 is 1.4 (rounded up). 24. Wind instruments and the laws they obey Blow the whistle. You can change the effective length of the whistle by moving the plunger.
PAGE 8
and F#’ is 9/8 and the interval between F#’’ and G’ is 16/15. This is achieved by taking the frequency of the F note and increasing it by multiplying it by 25/24. The new notes produced by sharpening the tones are called C#, D#, F#, G# and A#. (E# and B# are equivalent to F and C respectively). This sharpening is denoted in musical notation by a sharp sign appearing on the clave before the note.