Water is essential for life as we know it on earth. It is used by plants and animals for basic biological processes which would be impossible without the use of water. The origin of all life can be traced back to the water in the Earth s precambrien seas.
Water is also the universal solvent.
It reacts with more elements and compounds than any other substance known to man. Water is a polar molecule made up of on atom of hydrogen and two atoms of oxygen. It is attracted to itself by hydrogen bonds. Hydrogen bonds are weaker than covalent bonds, but collectively these bonds hold water together and give it its cohesiveness. The amount of energy needed to raise the temperature of one gram of water by one Celsius degree is called a Calorie.