[Illustration: FIG. 20.--Molten glass being rolled into a form
suitable for window panes.]
33. Strange Behavior of Water. One has but to remember that bottles
of water burst when they freeze, and that ice floats on water like
wood, to know that water expands on freezing or on solidifying. A
quantity of water which occupies 100 cubic feet of space will, on
becoming ice, need 109 cubic feet of space. On a cold winter night the
water sometimes freezes in the water pipes, and the pipes burst. Water
is very peculiar in expanding on solidification, because most
substances contract on solidifying; gelatin and jelly, for example,
contract so much that they shrink from the sides of the dish which
contains them.
|