WATER 101 - 



boils at 95, in Quito at 90. It would be possible- to' 

 the height of elevations by a determination made from 

 the boiling of water. What would be the effect of high 

 altitudes on the cooking of such foods as are prepared 

 by boiling? 



We have stated that liquids have a definite boiling 

 point under ordinary conditions. However, water will 

 pass into vapor at any temperature. Even ice and snow 

 evaporate or change to vapor directly, without passing 

 through the intermediate stage, water. This vapor 

 exerts a definite pressure which may be measured, but it 

 is very small at the lower temperatures. As the tem- 

 perature of the water rises, the pressure of the vapor or 

 steam increases until, at the boiling point, it has a pres- 

 sure equal to the pressure of the atmosphere, which we 

 have studied in terms of a column of mercury. If the 

 steam cannot then escape and the heating of the water 

 is continued, the pressure increases enormously until 

 in large volumes it is able to do a vast amount of 

 work, such as pulling a heavily loaded train of many cars. 



When water changes to steam, it increases enormously 

 in volume and of course becomes correspondingly lighter. 

 Steam is colorless, but when it escapes into the air there 

 is always a white cloud which is sometimes called steam. 

 This cloud is not steam, but is produced by little particles 

 of water caused by the condensation which takes place 

 when the hot steam comes in contact with the colder 

 atmosphere. 



Solutions. Salt dissolves in water. That is, when 

 salt is thrown into water, it disappears slowly, if left 

 to itself in the water, and more rapidly if the water is 

 shaken. A solid which behaves in this way when thrown 

 into a liquid is said to be soluble in that liquid. The 



