42 OTHER FACTS ABOUT HEAT 



water and would sink in ponds and lakes as fast as it formed, 

 and our streams and ponds would become masses of solid ice, 

 killing all animal and plant life. But the ice is lighter than 

 water and floats on top, and animals in the water beneath are 

 as free to live and swim as they were in the warm sunny 

 days of summer. The most severe winter cannot freeze a 

 deep lake solid? and in the coldest weather a hole made in 

 the ice will show water beneath the surface. Our ice boats 

 cut and break the ice of the river, and through the water 

 beneath our boats daily ply their way to and fro, independent 

 of winter and its blighting blasts. 



While most of us are familiar with the bursting of water 

 pipes on a cold night, few of us realize the influence which 

 freezing water exerts on the character of the land around us. 



Water sinks into the ground and, on the approach of 

 winter, freezes, expanding about one tenth of its volume ; the 

 expanding ice pushes the earth aside, the force in some cases 

 being sufficient to dislodge even huge rocks. In the early 

 days in New England it was said by the farmers that "rocks 

 grew," because fields cleared of stones in the fall became 

 rock covered with the approach of spring; the rocks and stones 

 hidden underground and unseen in the fall were forced to the 

 surface by the winter's expansion. We have all seen fence 

 posts and bricks pushed out of place because of the heaving 

 of the soil beneath them. Often householders must re-lay 

 their pavements and walks because of the damage done by 

 freezing water. 



The most conspicuous effect of the expansive power of freez- 

 ing water is seen in rocky or mountainous regions (Fig. 21). 

 Water easily finds entrance into the cracks and crevices of 

 the rocks, where it lodges until frozen ; then it expands and 

 acts like a wedge, widening cracks, chiseling off edges, and 

 even breaking rocks asunder. In regions where frequent 



