1. The Extraordinary Properties of Water

2. Water A water molecule (H 2 O), –one oxygen and two hydrogen. H H O Boils at 100 °CBoils at 100 °C Freezes at 0 °CFreezes at 0 °C

3. Hydrogen Bonds Formed between a polar molecule and a Hydrogen atom. - Formed between a polar molecule and a Hydrogen atom. -One hydrogen bond is weak, but many are strong.

4. Cohesion Attraction between particles of the same substance. -Water likes water Causes… Surface tension - a measure of the strength of water’s surface -allows insects to walk on the surface of water

5. Adhesion Attraction between two different substances. (glass, soil, plant tissues, and cotton.)

6. Capillary action -water molecules will “tow” each other along when in a thin tube. –plants and trees remove water from the soil (transpiration). –paper towels soak up water.

7. Water is Less Dense as a Solid Ice is less dense as a solid than as a liquid. (ice floats) - Liquid water has hydrogen bonds that are constantly broken and reformed. - Frozen water forms a crystal-like lattice whereby molecules are set at fixed distances.

8. Water is Less Dense as a Solid Which is ice and which is water?

9. Water is Less Dense as a Solid WaterIce

10. Homeostasis -Ability to maintain a steady state despite changing conditions. Water’s importance: a. Universal solvent b. Good Coolant (sweating, etc.) c. Floating ice protects living organisms against temperature extremes.