CONTENTS OF NATURAL WATER 31 



a. Make a simple calorimeter out of a measuring cup around 

 the sides and bottom of which you have sewed or pinned some 

 woolen material, such as flannel. A piece of cardboard, with a 

 hole for a thermometer, will do for a cover. If the cup is 

 graduated in fourths, you can measure the water that is used 

 by looking at the marks inside the cup. 



b. Put into the calorimeter J4 of a cupful of water at the 

 ordinary temperature, and get the temperature accurately. 

 Remove the cover for a moment, and put in ^ of a cupful of 

 water at 50 C. Put on the cover, and stir the water with 

 the thermometer. What is the temperature of the water now? 

 How near does it come to the temperature midway between the 

 ordinary temperature and 50 C.? 



c. Now pour out the water, put in J^ of a cupful at the 

 ordinary temperature, and f/2 & cupful at 50 C. Put on the 

 cover, and stir the water thoroughly. What is the resulting 

 temperature? How near is it to the temperature % of the way 

 from the ordinary temperature to 50 C.? 



EXERCISE 29 

 CONTENTS OF NATURAL WATER 



Apparatus and Materials. Beaker or measuring cup, flask (100 cu. 

 cm.), cork stopper and glass delivery tube, test tube, watch glass or 

 sheet of glass, tea kettle (?), water. 



a. Boil some hydrant water vigorously for 10 minutes, and 

 then let it stand. What settles out? Where did it come 

 from? How is a deposit formed on the inside of tea kettles, etc.? 



6. Distill water in the apparatus of Fig. 16. Half fill the 

 flask with hydrant water, and support it in a ring stand. Have 

 a piece of wire gauze between the flask and the flame. Use a 

 cork stopper and a doubly bent delivery tube, and catch the 

 distilled water in a test tube standing in a beaker of cold water. 



