Think of the most stubborn material in the universe which does not follow the law of Physics and Chemistry – it is none other than the plain water. Water does this only for life to sustain on earth. Had the water followed the established laws of Physics and Chemistry, the earth would be a lifeless planet.
A substance, when cooled, shrinks; it becomes denser and sinks. Water on the other hand expands when it freezes and becomes less dense. Water is densest at four degrees centigrade, hence ice floats on its own liquid. Due to this peculiar property aquatic life survives under frozen lakes, ponds, rivers, etc. The upper ice layer forms a protective conductor of heat. Had ice been denser than water; lakes, ponds, seas and oceans would freeze from bottom to top. All aquatic life would have vanished, and earth would be a dead planet.
Another peculiar property of water is its boiling temperature. Water H2o has two atoms of oxygen and one atom of hydrogen. Oxygen belongs to the group 16 in the Periodic Table, other elements belonging to group 16 are sulphur, selenium, tellurium. These elements combining with H forms H2S (hydrogen sulfide),H2Se(hydrogen selenide), H2Te(hydrogen telluride). H2S boils at -42oc, H2Te boils at -2oc, the lighter one must boil at lower temperature, water is lightest among them, by this logic water must boil at -70oc. That would mean water must not exist on earth as liquid. There would be no lakes, no rivers, no seas, no oceans.
Water has a peculiarly high specific heat. Its temperature does not rise rapidly as it does in metals. It absorbs heat and hides it without raising its temperature. Due to this property water regulates the temperature of the atmosphere and makes it liveable.
Water has high specific heat capacity of vaporisation; it takes lots of heat to convert water into vapor. That is why, when we sweat, evaporation takes lots of heat energy from our body to cool it. If water did not have this high heat of evaporation, we would be cooked up every time we run to catch a train.
Due to its high surface tension, water rises above its level in thin tubes. The thinner the tube, the higher the water rises. This is called the capillary effect. Trees and plants suck water from earth due to this capillary effect. Water can rise 300 feet high tree top without water pump. Had water not this peculiar property, no vegetation on the surface of the earth could have existed.
A lot of people, including science students, believe water to be a simple substance. But it is the most complex and misunderstood liquid. In fact, the entire science conferences were devoted to study water. The more one delves deeper to understand water, the murkier it becomes. It does so just to make life possible on earth.