1. How does the structure of water make life possible?

2. Water is a polar molecule
Electrons are shared unevenly.
The hydrogen side is slightly positive.
The oxygen side is slightly negative.
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3. Water forms hydrogen bonds.
Opposites attract!
The slightly negative oxygen side of a water molecule is attracted to the slightly positive side of another water molecule.
This type of attraction is called a hydrogen bond.
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4. Cohesion
As a result of hydrogen bonding, water molecules stick to other water molecules, a property called cohesion.
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5. Adhesion
Also because of polarity, water molecules stick to other types of molecules, a property called adhesion.
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6. Capillary action
Capillary action is an example of adhesion where water sticks to the sides of tubes.
Capillary action is biologically important.
Capillary action is the process that transports water in vascular plants.
Capillary action is at work in our smallest blood vessels, the capillaries.
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7. Water is less dense as a solid
Hydrogen bonding cause water molecules to form a rigid crystal structure as they freeze.
As a result, water expands when frozen and is less dense as a solid than as a liquid.
Ice floats
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8. Ice floating is important for life because . . .
Aquatic life can survive underneath frozen ice. The layer of ice actually provides insulation for water beneath.
Frozen ice helps keep fresh water accessible to living things (when it later melts).
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9. High heat capacity
It takes a lot of energy to change the temperature of water.
This property of water helps maintain a stable temperature environment for living creatures.
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10. “Universal” Solvent
Water can dissolve more substances than any other liquid.
Important chemical reactions for life take place in aqueous (watery) solutions.
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