1. Properties of Water

2. Hydrogen Bonds  Hydrogen bonds do not join atoms …
Hydrogen bonds are attractions between compounds

3. WATER

4. WATER Activity: (5 minutes) Create the structure of
water, including the hydrogen
bonds between molecules
(drawing, model, skit)

5. Hydrogen Bonds Give Water Unique Properties (Part I)
Heat Storage
A large input of thermal energy is required to disrupt the organization of liquid water
This minimizes temperature changes
High Heat of Vaporization
At high temperatures, hydrogen bonds do break
Water is changed into vapor resulting in a cooling effect

6. Heat Storage & High Heat of Vaporization
Water’s heat storage ability keeps temp of coastal areas more stable!

7. Properties of Water Heat Storage & High Heat of Vaporization
These properties allow water to trap lots of heat and take it away by evaporative cooling, like when you sweat!
Ahhhhh …

8. Questions to Ponder (Think, Pair, Share)
Where would you feel cooler on a 100 degree day: Las Vegas or Leesburg? Why?
Why do athletes like polyester more than cotton?
Where and why was Gatorade developed?
Why does it seldom (if ever) snow in San Francisco, even though it is similar in latitude to Leesburg?

9. Ice Formation  At low temperatures, hydrogen bonds don’t break
Water forms a regular crystal structure that floats

10. Ice is less dense than water, so ice floats!
This is super important because it prevents bodies of water from freezing solid and killing all life on the surface and underneath!

11. Question to Ponder Think-pair-share
At what temperature is the ice cover?
Estimate the temperature of the “blue water”. Which layers are warmer? Which are colder?

12. Hydrogen Bonds Give Water Unique Properties (Part II)
Hydrogen Bonds Give Water Unique Properties (Part II)
Water strider
Cohesion
Attraction of water molecules to other water molecules
Example: Surface tension
Adhesion
Attraction of water molecules to other polar molecules
Example: Capillary action

13. 
Surface Tension!
Cohesion (water to water) makes the surface of water like a “solid” film!

14. 
Surface Tension!
Demonstration

15. Capillary Action!  Cohesion and Adhesion Allows for Transpiration
- The movement of water up a plant (by “capillary action”) because of pull from evaporation through the leaves.

16. 
Capillary Action!
demonstration

17. Question to Ponder Think-pair-share
Question to Ponder Think-pair-share
Why does it hurt more to dive into the pool “spread eagle” (belly flop) than to dive in head first, and why?
Which is easier to siphon, water or diesel fuel, and why?

18. Water is a Great Solvent: Hydrophilic & Hydrophobic Substances
Hydrophilic (“water-loving”) substances
Polar
Hydrogen bond with water
Example: sugar
Hydrophobic (“water-fearing”) substances
Nonpolar
Repelled by water
Example: oil

19. Water is a Great Solvent: Hydrophilic & Hydrophobic Substances
demostration

20. Solute + Solvent = Solution
Solution
Solute + Solvent = Solution 
Solute- solid particles that dissolve
Solvent- what causes dissolving
Solution- homogenous mixture made from solute and solvent
Concentrated: when there is more solute than solvent
Diluted: when there is more solvent than solute

21. Solute + Solvent = Solution
Solution
Solute + Solvent = Solution 
demonstration

22. 0---------------------7-------------------14
The pH Scale 
Measures H+ concentration of fluid
Change of 1 on scale means 10X change in H+ concentration
Highest H Lowest H+
Acidic Neutral Basic
BUFFERS
Buffers are substances that resist pH changes! 

23. Acids & Bases  Acids These substances cause water to release its H+
Acidic solutions have pH < 7
Bases
These substances grab H+ from water, leaving behind OH- ions
Basic solutions have pH > 7