CHAPTER VIII 



WATER 

 FACTS ABOUT WATER 



Water. Water is one of the most abundant and widely dis- 

 tributed compounds on earth. Since it is a solvent for many sub- 

 stances it is never found pure in nature. When pure, however, it 

 is tasteless, colorless and odorless. Water is found in the majority 

 of things about us, -the papers we use, the wood in our homes, the 

 food we eat. For example, eggs and potatoes are three-quarters 

 water, solid rocks contain water, and even our 

 own bodies are 65 per cent water. 



Composition of Water. Water is composed of 

 two gases, hydrogen and oxygen. These gases are 

 called elements. An element is a substance which 

 can not be decomposed into simpler substances. 

 Scientists have found that there are only about 83 

 different elements, but by combining them in dif- 

 ferent proportions various kinds of substances may 

 be obtained. Thus by combining 2 parts of hy- 

 drogen with 1 part of oxygen, water is obtained. 



Electrolysis. Water may be separated into its 

 elements through a process called electrolysis. 

 Water is poured into the bowl of the apparatus 

 shown in the diagram until the two upright tubes 

 are full of water. A little sulphuric acid is added, 

 as the acid allows the current to pass through the 

 water. A battery is attached to the two platinum 

 sheets in the water at the bottom of the instrument. Bubbles of 

 hydrogen will be seen to rise in one tube and bubbles of oxygen in 

 the other. This process of separating the water into its elements 

 to determine its composition is. called electrolysis. 



257 



FIG. 162. 



