102 THE NATJJRE STUDY COURSE. 



Try to borrow a stone-chisel and hammer to drill a hole, 

 widening downward into a lump of limestone or other kind of 

 rock. Fill the hole with water and set it out to freeze solid. 

 Observe the result. 



What kinds of water containers are sometimes burst by 

 frost ? Lead-pipes, pails and iron pots may be mentioned. 



Float a cube or other easily measured block of ice in cold 

 water. Obtain the ratio of the height of the emerged part to 

 the height of the whole block. 



Measure the cubic contents of the block of ice and weigh it. 

 Melt it and weigh the resulting liquid. One cubic foot of 

 water weighs 1,000 ounces ; calculate from this fact the 

 volume of water obtained from the ice. 



The experiments, if carefully made, should show that there 

 is no loss of weight due to melting, but the volume is reduced 

 one-eleventh. Compare this ratio with that of the height 

 measurements. 



Now have pupils infer why ice floats in water, how it can 

 make soil out of rocks and burst vessels of glass, wood, lead 

 and iron. 



The Weight of Equal Volumes of Water and Ice. — Apply 

 your experiments to determine the weight of eleven cubic feet 

 of ice. 



What volume of ice will ten cubic feet of water make % 



What weight of water will be obtained from melting a 

 block of ice 3 feet long, 22 inches wide, and a foot thick 1 



If you have the means of weighing a piece of ice, both in 

 air and in water, determine its specific gravity by dividing its 

 weight in air by its loss of weight when weighed in water. 

 The ice has to be loaded to cause it to sink. Or, float the ice 

 in a vessel brimful of water ; prepare to collect the overflow 



