SOLUTION 



95 



10. Why is water from springs usually clear, while 

 water in rivers is dirty? 



36. Solution. 



When we put sand or sawdust into water we could 

 still see it. Can you see sugar when you have put a little 

 into water and have stirred it well? If a solid disappears, 

 when put into a liquid, we say that the solid dissolves, 

 and we call the result a solution. Not only does water 

 dissolve solids but it can also hold gases in solution. 

 Any liquid which can dissolve solids or gases is called a 

 solvent. In Section 28 we saw that water can hold con- 

 siderable air in solution if the water were cold. The best 

 way to learn more about solution is by experimenting. 



Experiment 48. Solution and its .Oddities. 



Apparatus: Two glasses, tin spoon, burner, tin 

 cans, thermometer, funnel, filter paper, glass rod. 



Materials : Sugar, salt, baking soda, cream of tar- 

 tar, ammonium chloride (commonly called sal ammoniac). 



a Fill a glass full of water. Very slowly add 

 some sugar while carefully stir- 

 ring. Note that it is possible to 

 add considerable sugar without 

 making the water overflow. Now 

 add some salt in the same way 

 to the same water. Can you do 

 it without making the water 

 overflow? What is one of the 

 oddities of solution? Try filter- 

 ing the solution. Do the sugar 

 and the salt pass through? The 

 method of pouring liquids from a 

 glass is shown in the illustration. 



