132 



GENERAL SCIENCE 



sion of water, plotting scale readings on the horizontal axis and 

 thermometer readings on the vertical axis. 



We have already spoken of the 

 great importance of the irregular 

 expansion of water. Review it 

 here. 



Expansion of Gases. Gases are 

 no exception to the rule that heat 

 expands matter. The effect of heat 

 on gases is very marked. Since the 

 molecules are farther separated in 

 gases than in other forms of matter, 

 the application of heat greatly in- 

 creases their speed and their ex- 

 pansive force. 



Experiment 35. Fit a Florence flask 



with a one-hole rubber stopper and a 



glass tube twenty inches long (Figure 



116). Invert this apparatus in a vessel 



of water and apply heat to the flask. 



What happens? Allow the flask to cool. Why does the water 



ascend ? How could the amount of expansion of the air in the flask 



be determined ? 



If several gases 

 are tested, it will 

 be found that they 

 expand about the 

 same amount for 

 each degree of 

 temperature and 

 not irregularly as 

 do solids and 

 liquids. A gas ex- 



FIG. 116. Expansion of Gases. pands 2T3" f ^S 



FIG. 115. Expansion of 

 Liquids. 



