160 



MECHANICS 



b. Repeat, using a block of wood. Do floating 

 bodies displace any water? Do they displace as much 

 as they would if they sank? 



c. Measure the block of wood in centimeters and 

 find how many cubic centimeters it contains. Then fill 

 a glass completely full of water, place the glass in an 

 empty jar, or in a deep saucer, and push the block beneath 

 the surface of the water in the glass. The amount of 

 water which overflows should contain very nearly the 

 same number of cubic centimeters as you have just 

 obtained from measuring the block. Measure the water 

 carefully with the graduate and see how exactly you have 



performed the experiment. Now 

 you can tell how to measure the 

 volume of a stone or any irregular 

 body. Explain. 



d. Arrange the apparatus as 

 shown in the illustration and push 

 the funnel deeper and deeper into 

 the water. Does the water go up 

 into the funnel? Does air occupy 

 space? Can you explain what 

 happens in the bent tube? 



61. Density. 



People have long used the sayings "As heavy as 

 lead" and "Light as feathers" without meaning just what 

 they said. They really meant to say that a certain 

 volume of feathers is much lighter than the same volume 

 of lead. When we tell how much a certain volume of a 

 material weighs we are giving its density. Since equal 



