1 \u2013 Frozen ice is less dense than liquid water. That is why ice cubes float in your drink!<\/p>\n\n\n\n
2 \u2013 In fact at positive 4 \u00b0C , water is the most dense. Colder than that , and the density decreases , and also warmer than that , the density decreases.<\/p>\n\n\n\n
3 \u2013 4 degrees Celsius turns out to be the temperature at which liquid water has the highest density. If you heat it or cool it , it will expand. The expansion of water when you cool it to lower temperatures is unusual , since most liquids contract when they are cooled.<\/p>\n\n\n\n
4 \u2013 An interesting consequence of this peculiar feature of water is that the temperature of water at the bottom of a lake in the winter is almost always 4 degrees C , since the densest water will settle to the bottom . If it gets any colder or warmer , it will rise. Ice floats on top of lakes , preventing evaporation and convection in the frozen layer , and lakes stay liquid underneath , allowing fish and other life to survive.<\/p>\n\n\n\n
5 \u2013 This is a very special property of water. Almost every other type of matter gets more dense when it changes phase from a liquid to a solid , but water gets less dense. Why? Because ice is a crystal , which means it has a regular pattern with spaces in between molecules. The spaces in the crystal are larger than the spaces between molecules in the liquid. More space = less dense, so ice is less dense than water.<\/p>\n\n\n\n
6 \u2013 The amazing fact that water freezes on the surface of a lake but not below it allows plants and fish to live through the winter.<\/p>\n\n\n\n
7 \u2013 Generally , all liquids expand on heating , but water is an exception to this rule. If water is heated, its volume gradually decreases. (This decrease in volume continues till the temperature rises to 4 \u00b0C.) At temperatures over 4 \u00b0C water starts expanding. It then keeps expanding with the further rise in temperature , till finally at 100 \u00b0C it turns into steam.<\/p>\n\n\n\n
8 \u2013 If ice were heavier than water , it would sink to the bottom eventually whole of the lake would freeze , destroying any life in it. Can you imagine what would happen to aquatic life if the lake froze solid every winter?<\/p>\n\n\n\n