1. Water, Water Everywhere!
Essential Questions:
What are the properties of Water?
What are Mixtures, Solutions and Suspensions?
Why is water important for living things?
What is the pH scale?

2. Your turn! What do you know about the properties of water?

3. Introduction to Water Water makes up 70-95% of organisms.
Consists of 1 Oxygen atom and 2 Hydrogen atoms per 1 water molecule.
How is water bonded?
Because of its bonding it can hold large molecules like proteins together.
Carries substances via Osmosis.
Serves as material transportation
Blood, plant sap
Cycles through the kidneys and eliminated out of the body

4. Five Major Properties of Water
Water is liquid at room temperature
boiling point is high at 100° C
low molecular weight
molecules are usually gaseous.
Water resists temperature change. Because the boiling point is so high, It takes a lot of energy to heat water. ‏
Water exists in three phases:
Solid (ice)
Liquid (“water”)
Gas (vapor)‏

5. Five Major Properties of Water
Water has a high freezing point
Ice is less dense than water.
(Thus, ice floats in water.)

6. Five Major Properties of Water
Water is the universal solvent for polar and ionic molecules (it can dissolve other liquids, solids, or gases)
Polar: Water has a slightly positive (+) end and a slightly negative (-) end.
Hydrophilic: means “water-loving”, molecules that interact with water, soluble in water
Hydrophobic: means “water-fearing”, insoluble in water

7. Five Major Properties of Water
4. Water is wet:
Hydrogen bonds hold separate water molecules together (polar areas attract)
Slightly negative (-) Oxygen end is attracted to the slightly positive (+) Hydrogen ends.
Cohesion: attraction of water molecules to each other.
Adhesion: attraction of water molecules to other types of molecules.
Example: The meniscus in a graduated cylinder
Capillary action : cohesion and adhesion act together, pulling up water against gravity.
Example: Transportation of water from the roots to the leaves of a tree

8. Five Major Properties of Water
5. Water has high surface tension
water is more attracted to itself (cohesion) than to the air around it
Sticks together (+ and – attract.)
You will determine factors that affect
Surface Tension in your Penny Mini-lab today!

9. Mixtures, Solutions & Suspensions
Signs of Dehydration
A mixture is a combination of substances where both substances keep their original properties.
Physically mixed, not chemically mixed.

10. Mixtures, Solutions & Suspensions
Solution: one or more substances (solutes) are distributed evenly in another substance (solvent), like water
The more solute in a solvent, the higher the concentration
Homeostasis: Organisms regulate the concentration of water and other important substances in their bodies to maintain a certain stable concentration for life processes
Signs of Dehydration

11. Mixtures, Solutions & Suspensions
Signs of Dehydration
Suspension – mixture of water and non-dissolved particles
Example: Blood

12. pH Scale pH – a measure of how acidic or basic something is.
Use pH paper (litmus paper) to test
Acids range from pH of 0-6
Acids form H+ ions in water
Example: Lemon (pH: 2)‏
Neutral is 7
Example: Pure water and blood (pH: 7)‏
Bases range from pH of 8-14
Bases form OH- ions in water
Example: Ammonia (pH: 12)‏
Buffers – weak acids and weak bases that react with strong acids or bases to prevent sudden changes in pH.
Used to maintain homeostasis.

13. Homeostasis
The ability or tendency of an organism to maintain internal equilibrium, or balance, internally.

14. Fight Club Science: Neutralization Reaction
In the Movie, Fight Club, Brad Pitt’s Character puts a chemical burn (using Lye, pH of 13) on Edward Norton’s Character's wet hand.
Is lye an acid, a base or a neutral substance?

15. Fight Club Science: Neutralization Reaction
In the Movie, Fight Club, Brad Pitt’s Character puts a chemical burn (using Lye, pH of 13) on Edward Norton’s Character's wet hand.
Is lye an acid, a base or a neutral substance?
Should he put water or vinegar to stop the burn?
What is the pH of Water?
What is the pH of Vinegar?

16. Fight Club Science: Neutralization Reaction
In the Movie, Fight Club, Brad Pitt’s Character puts a chemical burn (using Lye, pH of 13) on Edward Norton’s Character's wet hand.
Is lye an acid, a base or a neutral substance?
Should he put water or vinegar to stop the burn?
What is the pH of Water?
What is the pH of Vinegar?

17. Properties and biological roles of water

18. Penny Minilab!