1. Can you die from drinking too much water?
Take notes from this video

2. WATER AND SOLUTIONS Page 39-44
BIOLOGY
WATER AND SOLUTIONS
Page 39-44

3. BY THE END OF THIS LECTURE, YOU WILL BE ABLE TO:
LECTURE OBJECTIVES
BY THE END OF THIS LECTURE, YOU WILL BE ABLE TO:
1. Explain how water’s polar nature affects its ability to dissolve substances.
2. Outline the relationship between hydrogen bonding and the different properties of water.

4. WATER! Water is essential to life because of its structure
The water molecule is one oxygen atom and two hydrogen atoms that are bonded COVALENTLY (they share electrons)
See pictures on page 39 of text
Explain the structure of an atom (protons, neutrons, electrons) and that bonds hold atoms together.

5. POLARITY
The total charge on a water molecule is NEUTRAL (no charge) BUT the charge is not the same on both sides
Water is called a POLAR molecule because the charge is different on 2 sides

6. SOLUBILITY OF WATER OPPOSITES ATTRACT!
Because a water molecule is POLAR, other polar molecules will dissolve easily in water
OPPOSITES ATTRACT!
Explain that “-” side of water molecules are surrounding Na+ and that “+” side of water molecules are surrounding Cl-

7. Because water is POLAR water molecules stick to themselves
HYDROGEN BONDING
Because water is POLAR water molecules stick to themselves
Water molecules are held to each other by HYDROGEN BONDS
These bonds form, break, and reform A LOT

8. 1st PROPERTY OF WATER:
Water molecules sticking to each other is called COHESION
Water molecules sticking to something else (like glass) is called ADHESION

9. TEMPERATURE MODERATION
2nd PROPERTY OF WATER:
TEMPERATURE MODERATION
Water has a HIGH HEAT CAPACITY, which means it can absorb or release a lot of energy without a big change in temperature
The temperature of water goes up only after all the hydrogen bonds are broken

10. Examples: Example: The oceans stabilize global temperatures
Example: Organisms can keep their cells (that are mostly water) the same temp. even though the outside temp. changes
Example: Sweating water which releases body heat

11. 3rd PROPERTY OF WATER: DENSITY OF ICE:
Because the hydrogen bonds form at a certain angle there is a lot of space between molecules when frozen
So, ice (which is a SOLID) is LESS dense than water (which is a LIQUID)
Bodies of water freeze from top down, allowing life to exist below icy surface

12. REVIEW:
Explain how water’s polar nature affects its ability to dissolve substances:
Outline the relationship between hydrogen bonding and the different properties of water: