PURE WATER 



75 



Let your report include all details of your processes, and also a 

 report on the results of any attempts to stop the loss. 



What if similar leaks occurred in half the faucets in town? 



Pure water. What is pure water ? We have already 

 seen water condensed as a product of a burning candle, 

 and in a future chapter we shall see that it is the product 

 of burning hydrogen in oxygen. It is, then, a compound 

 produced by the combination of the chemical elements, oxy- 

 gen and hydrogen. All pure water contains hydrogen and 

 oxygen and nothing else. When other substances are mixed 

 with water there are certain methods by which pure water 

 may be separated from some or all of the impurities. One 

 purifying process is distillation. Let us see if this gives 

 us pure water from impure water. 



Experiment. To find a method of purifying water. 



Materials: Two 500 cc. flasks. A one-hole rubber stopper. Glass tube. 



Ring stand. 

 Method: Prepare a sample of impure water by adding a teaspoonful of 



salt and an equal amount of clay or fine sand, and a few crystals of 



potassium permanganate to a half pint 



of water. Fill one flask about half 



full of the prepared water and place 



on ring stand. Arrange to carry the 



steam through a bent glass tube into 



the other flask which stands under a 



stream of cold water. Heat the flask 



which is supported on a ring stand. 



When an inch depth of distilled water 



has been prepared remove the heat. 

 Results and Conclusion: How does the 



distilled water compare with the 



original in appearance? In taste? 



What can you say regarding distillation as a method for purifying 



water? Are any of the impurities left in it? Explain fully the pro- 

 cess of distillation. . 



Distillation apparatus. 



