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THE WATERS OF THE EARTH 



into the beaker, weigh the beaker with the water in it. Subtract the 

 weight of the dry beaker from the weight of the beaker containing 

 water, and you will have the weight of the water displaced by the 

 block of wood. Compare this weight with the weight of the block. 

 Mark on the block the depth to which it sinks. About how 

 much of the block was submerged ? 



A body floating in water displaces its own weight of water. 

 Thus if a body is half as dense as water, it will sink half 



AN AMERICAN SUBMARINE 



U. S. official 



its volume ; if one third as dense, it will sink one third its 

 volume. Representing the density of water by 1, what deci- 

 mal fraction would represent the approximate density of the 

 wood in the experiment? The density of any substance as 

 compared with the density of water is known as the specific 

 density of the substance. A solid piece of iron is much 

 denser than water and when submerged displaces much less 

 than its own weight of water. It therefore sinks. But an 

 iron dish will float because its volume is so great that it 

 displaces a weight of water equal to its own weight. If a 

 hole is made in the dish and water is allowed to enter the 



