DENSITY 161 



volumes of feathers and lead do not weigh the same, 

 people should say that lead has a greater density than 

 feathers. How would a pound of feathers compare with 

 a pound of lead? 



We are often more interested in knowing the density 

 of materials than in knowing their weight. The density 

 can always be obtained by dividing the total units of 

 weight by the total units of volume, and is expressed as so 

 many pounds per cubic foot, so many ounces per cubic 

 inch, or so many grams per cubic centimeter, or, in fact, in 

 any units of weight and any units of volume. Thus we 

 say that the density of water is 62.4 pounds per cubic 

 foot or nearly .6 of an ounce per cubic inch, or 1 gram 

 per cubic centimeter. Which is the simplest expression? 



Experiment 67. Density. 



Apparatus: Balance, set of weights, blocks of wood, 

 pieces of stone, brick, lead, iron, zinc, or any kind of 

 material weighing not over '200 grams; glass, large jar, 

 graduate. 



a. Weigh each object and make a record of the 

 weights. Find the volume of each object by means of the 

 displacement of water and record the volumes. Divide 

 the units of weight of each object by the units of volume 

 of the same object. This gives the density of each object. 



How do your answers compare with densities which 

 are given in the table? If they are not quite close, repeat 

 using other pieces of the material. 



You should arrange your work as follows: 



Elem. Sci. 1 1 



