WEATHER AND CLIMATE 



69 



THE THERMOMETER 



1. Close a test tube filled with cold water with a rubber 

 stopper through which passes a glass tube, and have the 

 water stand above the stopper. Mark the water level in 

 the glass tube by tying a thread around the tube. 



Warm the water in the test tube, and observe the effect 

 as shown in the glass tube. Warm more 

 and more, and observe further. 



Cool the test tube more and more, and 

 explain any changes. 



State the general relationship apparent 

 between change in temperature and change 

 in volume. What is meant by the tem- 

 perature of a body? 



2. Put a chemical thermometer having 

 both centigrade (C.) and Fahrenheit (F.) 

 scales into water, and take the readings of 

 the mercury level when stationary in both 

 C. and F. degrees. (Estimate any fraction 

 of a degree in either case as tenths rather 

 than halves, and quarters, and use decimals -ir.s 

 rather than common fractions in writing 

 results.) 



Note how many spaces of the Fahren- 

 heit scale the F. is below C. (the place 



, - FIG. 30. Fahren- 



where the mercury level stands when the heit and centi- 

 thermometer is in freezing water). The 

 temperature of the water is how many F. 

 degrees above the zero of the C. reading? Calculate the 

 number of F. degrees (spaces) to which one C. degree of 

 the thermometer stem is equal. (Carry the division out 



grade scales in 

 thermometers. 



