The Importance of Water to Life on Earth.

Essay by mattuCollege, UndergraduateA+, January 2006

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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 successful ecosystem and how important it is to us today.

Each water molecule consists of one oxygen atom and two hydrogen atoms. The oxygen atom bears a slight electronegative charge while hydrogen possesses a more positive one. 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 formed. In an ice crystal the hydrogen bonds govern the shape of the crystal so that the grid of molecules surrounds relatively large spaces. 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 -75 degrees C and a freezing point of -125 degrees C4. This would mean that, on Earth, water would be a gas all of the time and life would not be possible.

When heat is applied to solid water, some hydrogen bonds get so much...