1 88 Common Science 



In general, the longer or larger the object is that 

 vibrates, the slower the rate of vibration and conse- 

 quently the lower the pitch. But the shorter or 

 finer the object is that vibrates, the higher the rate of 

 vibration and the higher the pitch. 



All musical instruments contain devices which can 

 be made to vibrate, either strings or columns of air, 

 or other things that swing to and fro and start waves 

 in the air. And by tightening them, or making them 

 smaller or shorter, the pitch can be made higher ; that 

 is, the number of vibrations to each second can be in- 

 creased. 



Application 44. Explain why a steamboat whistle is 

 usually of much lower pitch than is a toy whistle; why a 

 banjo player moves his fingers toward the drum end of the 

 banjo when he plays high notes ; why the sound made by a 

 mosquito is higher in pitch than that made by a bumblebee. 



Application 45. A boy had a banjo given him for Christ- 

 mas. He wanted to tune it. To make a string give a 

 higher note, should he have tightened or loosened it? Or 

 could he have secured the same result by moving his finger 

 up and down the string to lengthen or shorten it? 



Application 46. A man was tuning a piano for a concert. 

 The hall was cold, yet he knew it would be warm at the time 

 of the concert. Should he have tuned the piano to a higher 

 pitch than he wanted it to have on the concert night, to the 



exact pitch, or to a lower pitch ? 



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Inference Exercise 



Explain the following : 



271. A cowboy whirls his lasso around and around his head before 



he throws it. 



272. Furnaces are always placed in the basements of buildings, 



never on top floors. 



