36 GENERAL SCIENCE 



and measures will not correspond numerically to the 

 specific gravity. 



A cubic foot of water weighs 62.3 pounds or about 

 1000 ounces, while by definition a .cubic centimeter of 

 water weighs one gram. 



Densities of Liquids and Solids in Grams per Cubic 

 Centimeter 



LIQUIDS 



Alcohol ' .79 Hydrochloric acid . . ... 1.27 



Glycerine 1.26 Mercury. . .. ' . . . 13.6 



SOLIDS 



Aluminum ...... 2.58 Lead 11.3 



Brass . 8.5 Pine 5 



Copper . . . . . . . 8.9 Platinum 21.5 



Cork . .... . . .25 Silver . . 10.53 



Glass 2.6 Tin 7.29 



Gold 19.3 Zinc 7.15 



Iron (cast) ..... 7.4 



QUESTIONS AND PROBLEMS 



1. A tank is 2 feet deep, 3 feet wide, and 5 feet long. What 

 weight in pounds of water can it hold ? 



2. A rectangular block of iron is 10 cm. long, 4 cm. deep, and 3 cm. 

 wide and weighs 888 grams. What is the density of the iron? 



3. Find the weight of 5 cubic centimeters of glycerine. 



4. How does a molecule differ from an atom? 



5. Name ten special properties of matter. 



6. In what respects does a liquid differ from a gas? 



7. Make a list of properties of the following substances : chalk, 

 glass, coal, lead, and salt. 



8. Why should a barrel have a vent hole in it ? 



9. How does iron differ from copper? 



10. Do you see any advantages of the metric system over the 

 English system? 



11. What difficulties would there be in changing from our system 

 to the metric system for all measurements? 



