Free Essays, Term Papers, Research Papers at Anti Essays

Water is the most important substance in our evolution and our daily lives. Without water,

life as we know it would not have been possible. This essay will examine the water molecule

in order to ascertain how it brought about Earth's thriving ecosystem and how important it

is to us today.



Each water molecule consists of one oxygen atom and two hydrogen atoms. The oxygen atom (or

the apex of the water molecule) bears a slight electronegative charge while hydrogen

possesses a more positive one1 (figure a). Because opposite charges attract, the water

molecules are drawn together. When an oxygen atom is linked to a neighboring molecule's

hydrogen atom, a bond called a hydrogen bond is formed2. In an ice crystal the hydrogen

bonds govern the shape of the crystal so that the grid of molecules surrounds relatively

large spaces (imagine figure b in three dimensions). In a liquid form, water has no such

spaces; thus ice is less dense and will float on liquid water. If not for this, great bodies

of water would freeze from the bottom up without the insulation of a top layer of ice and

all life in the water would die.





The water molecule is a very small one but because of its unique properties it behaves like

a larger one. The bonds between water molecules are so strong that water resists changes in

its state (Solid, liquid, gas); thus water has a higher melting point and a higher boiling

point than another molecule of similar size. If water followed the example of other

molecules its size it would have a boiling point of -75øC and a freezing point of -125øC4.

This would mean that, on Earth, water would be a gas all of the time and life would not be

...