WHAT USES DO WE MAKE OF WATER? 97 



SELF-TESTING EXERCISE 



Select from the following list those words which best fill the blank spaces 

 in the sentences below and arrange the words in proper numerical order. 

 A word may be used more than once. 



salt bluing solution 56 steam acid 



liquid solid ice boil gas boiling 



solvent dissolve form heat evaporation fuels 



mix soap emulsion mixture washing dissolves 



oils water boiling oil 65 freezing 



Water is ordinarily a (1) , but in very cold regions it is a 



(2) called (3) When heated strongly on the stove, 



water will (4) , but if left in the open air, it changes to a (5) 



in the process of (6) When salt is stirred in water, it disap- 

 pears because water is an excellent (7) Water will not 



(8) insoluble substances. The (9) or condition of water 



is determined by the amount of (10) it contains. Oils which 



do not readily (11) with water are made to do so by the 



addition of (12) The result is called an (13) In the 



process of cleaning, water is aided greatly by the addition of 



(14) Much of the dirt we try to remove in the process of 



(15) is held by fats or grease or (16) Soap in (17) 



forms an (18) with the fat or (19) and so loosens the dirt. 



People need to drink much water because it helps carry foods 



and remove waste and because the body itself is (20) per cent 



water. 



STORY TEST 



ALTON RELATES His EXPERIENCES ON SOLUBILITY 

 Read carefully and critically. List all the errors and suggest corrections. 



I will tell you of my experiment on testing solubility of substances 

 in water which I did at home. I found that water will dissolve 

 salt and " absorbent " cotton. I presume this kind of cotton is 

 called " absorbent " because the water absorbs it and makes a 

 solution of it. Water will not dissolve ashes or soap chips. I 

 found that oil would not dissolve in water alone, but if I put soap 

 in the water with the oil and shook or stirred vigorously, the oil 

 did not separate. This is because it had dissolved in the water. I 

 boiled some water from a deep well until the water disappeared ; 

 a small amount of solid was left. I put coffee grounds into water 

 and boiled it. I poured the liquid off and the grounds were left, 

 therefore there is no solution formed when one " makes coffee." 



H. & W. SCI. I 8 



