TEMPERATURE AND ITS MEASUREMENT 21 



and insert the stopper. This will cause the water to run up 

 the tube a short distance. Place flask over the asbestos mat, 

 on ring stand, and heat slowly. Should you say that expan- 

 sion is proportional to the change in temperature ? 



c. Screw each screw eye into a piece of wood to serve as 

 handles. Heat the smaller screw eye, and then see if it will 

 pass through the larger screw eye. State two methods which 

 may be employed to enable you to accomplish this. Tell 

 what would be the result if you had placed the larger screw 

 eye in some freezing mixture instead of heating the smaller 

 screw eye. 



16. TEMPERATURE AND ITS MEASUREMENT 



In considering heat, we learned that it was due to the mo- 

 tions of the molecules of a body. If one body is giving heat 

 to another body, we say that the intensity of heat of the first 

 body is greater than that of the second body. This intensity 

 of heat is called temperature, and, as has been stated, tem- 

 perature is usually measured by the expansion of some 

 material. Mercury is the material used for ordinary tem- 

 peratures, as its expansion is almost proportional to change 

 in temperature, but colored alcohol is used for temperatures 

 which are very low, while in extreme cases the gas thermome- 

 ter is used. 



There are two scales of temperature, the " Fahrenheit," 

 and the " Centigrade " or " Celsius." In the Fahrenheit 

 scale, thirty-two degrees is arbitrarily taken as the freezing 

 point of water, and two hundred and twelve degrees as the 

 boiling point of water. Zero is merely thirty-two degrees 

 below the freezing point. In the Centigrade thermometer, 

 zero is taken as the freezing point, and one hundred degrees 



