|
Begin by drawing a diagram that shows the structure of a water molecule. Add + and - symbols to your drawing showing the manner in which electrical charge is distributed across the water molecule. Is water a polar substance? Why or why not? Now add several more water molecules to your diagram, arranging the molecules on the diagram in a manner that shows how they would interact in liquid water. What properties of the water molecule account for this arrangement?
Search the web to find some of the chemical and physical properties of water, for example, melting point, boiling point, surface tension. What feature of water explains these properties? How do these properties compare with those of other fluids, such as alcohol or mercury? What other physical properties of water can you find? How do these compare with other fluids?
How have living things evolved to take advantage of these physical properties? For example, how do animals and plants use the high heat of vaporization to stay cool? What other physical properties of water do organisms take advantage of?
Learn about how water is cycled on Earth. At any given time, what proportion of Earth's water is liquid? What proportion is vapor? Follow a possible pathway of a single water molecule through its different phases on Earth. The discussion in Chapter 15.2.2 of the text and CD can help you.
Why do we believe that life originated in liquid water? Are there other places in the solar system in which we know water exists as a liquid? The universe? What implications does this have for the possibility of life elsewhere in the universe?
|