172 EXPERIMENTAL GENERAL SCIENCE 



26. Strike a tuning fork and immediately hold the base of the fork on 

 the top of a wooden table or a wooden box. Explain the sound produced. 



26. Strike the fork again and hold it over the mouth of a tall cylinder. 

 Pour water into the cylinder, a little at a time, until you get a clear note 

 from the cylinder. How does the column of air in the cylinder, vibrating 

 in sympathy with the fork, affect the original sound? 



27. Try a tuning fork of a different size. Does the air column vibrate 

 with any sound or only those with which it is in sympathy? 



28. Using the loud pedal of the piano, sound a full note with the voice 

 and account for the response from the piano. 



29. Why do the windows of a church sometimes rattle when a particu- 

 larly deep note is played on the organ? 



30. Draw a small glass tube out to a slender point, attach it to a gas 

 jet by a rubber tube, fix in an upright position, and light the gas. Now 

 slowly pass a longer and larger tube over the flame. Account for the 

 sound produced. 



31. What gives resonance to the flute or fife? 



32. What gives resonance to the drum? 



33. What part of the respiratory tract gives resonance to the human 

 voice? 



34. How many notes in the musical scale? 



35. Is there a single scale or will any other series of tones with the 

 same difference in vibration produce a scale? 



36. In the xylophone, a scale is produced by pieces of wood of different 

 lengths. Explain. 



