1. Properties of water
Biology

2. Warm Up
Select the correct choice: What type of bond results when valence electrons are shared between two atoms?
Ionic bond
Hydrogen bond
Covalent bond
Weak bond
For each number below, answer the following
A. Is it a compound or an element?
B. What does each letter stand for?
C. How many atoms of each element is there:
1. C57H110O6
2. H20
3. H
4. NaCl
5. N

3. 1. Which of the following best defines the word “vapor” found in the first paragraph?
a. Water found in liquid form
b. Hydrogen bonds
c. The form water is in after it boils
d. The energy in water
2. Which of the following best defines the word “regulate” found in the second paragraph?
a. To absorb heat
b. To make stable
c. To create cohesion
d. To use chemical energy and release heat
3. Which of the following best defines the word “vessels” found in the fourth paragraph?
a. Passages that carry water from roots to leaves
b. Water molecules that stick to other things
c. A type of adhesion
d. Cargo ships

4. Instructional Focus Lesson – you do
Which of the following best defines the word “vapor” found in the first paragraph? a. Water found in liquid form b. Hydrogen bonds c. The form water is in after it boils d. The energy in water

5. Instructional Focus Lesson – you do
Which of the following best defines the word “regulate” found in the second paragraph? a. To absorb heat b. To make stable c. To create cohesion d. To use chemical energy and release heat

6. Instructional Focus Lesson – you do
Which of the following best defines the word “vessels” found in the fourth paragraph? a. Passages that carry water from roots to leaves b. Water molecules that stick to other things c. A type of adhesion d. Cargo ships

7. Daily Objectives SWBAT: What does polarity mean?
SWBAT: Distinguish between covalent bonds and hydrogen bonds.
SWBAT: Describe the following properties of water: cohesion, adhesion, expansion upon freezing, solubility, and temperature moderation.
SWBAT: justify why the properties of water make life possible

8. Instructional Focus Lesson
1. Read the provided article
2. As you read the article, write any unknown words you find.
3. What are some dangers of the chemical discussed in this article (list 3)

9. Warm Up
Write down 2-3 observations from the water lab we did last class.

10. Today’s Objectives
You will be able to explain the weird properties of water that make life possible.
You will be able to explain the shape of a water molecule

11. Focus Lesson Read the three paragraphs of page 44.
1. Which of the following best defines the word “unpaired” found in the second paragraph?
a. unique
b. alone
c. without equal
d. Twin
2. Which of the following best defines the word “fundamental” found in the third paragraph?
b. covalent
c. enjoyment
d. necessary

12. I. Structure of a Water Molecule
A. Structure
1. Water is composed of 1 oxygen atom and 2 hydrogen atoms.
2. The oxygen has a negative charge and the hydrogen has a positive charge.

13. I. Structure of a Water Molecule
B. H20 is considered polar because it is NOT completely symmetric.
What does symmetric mean?

14. Symmetric vs Asymmetric (whiteboard)

15. Practice with Charges! (4 min)
Draw the following diagram (doesn’t need to be 3D)
Label the hydrogen and oxygen.
Label the charges for each atom.

16. Practice with Structure!
Which diagram of a water molecule is correct?
Choose the answer AND explain why. A B D C

17. II. Hydrogen Bonding
A. Bond that occurs between the oxygen and hydrogen atoms in a water molecule.
1. Opposite charges attract; like charges repel.
2. Hydrogen bonds are very weak.

18. Explore with Pennies!
Predict what property of water this displayed.

19. III. Cohesion
A. Cohesion is the attraction of water molecules to each other.
1. It creates a high surface tension in water.
Let’s decode “surface tension.”
2. That means that surface is “tense.” Allows leaves to float and insects to walk across surface of water.

20. Explore with Paper Towels!
Predict what property of water was displayed with the paper towels.

21. IV. Adhesion
A. Adhesion is the attraction of water molecules to other substances.
B. Adhesion allows water to travel against gravity.
How does water get to the top of the tree if I only watered the soil?

22. Practice with Adhesion & Cohesion (whiteboard)
What property of water does this each picture represent? 1. 2. 3.

23. Practice with Adhesion & Cohesion
4. What property of water allows water spiders to walk across the surface of a pond?
A. Ph.
B. Adhesion
C. Cohesion
D. It is non-polar, and neighboring molecules fail to interact with each other.
5. Water is able to move against gravity because:
A. Adhesion of water molecules with themselves
B. Cohesion of water molecules with themselves
C. Cohesion of water molecules to other surfaces
D. Adhesion of water molecules to other surfaces

24. V. Solubility of Water
A. Solubility is the ability of substances to dissolve in water.
1. Water is a universal solvent.
2. It can dissolve almost anything.

25. V. Solubility of Water
B. The reason why salt dissolves is because the charges in salt interact with the charges in water.

26. VI. Density of Ice & Liquid Water
A. Density is how “tightly packed” a substance is.
1. Objects with higher density will sink.
2. Objects with lower density will float.
B. Ice is less dense than water
1. Because H-bonding creates more space when frozen
Will ice float?

28. VI. Density of Ice
Ice is less dense than liquid water because ice expands when it freezes.
C. Floating ice will keep the water underneath warm.
1. This allows fish and other organisms to survive.

29. VII. Water Keeps Temperature Stable
A. It takes a lot of energy to change the temperature of water.
B. Because it takes so much energy, water temperature doesn’t change much.
In the picture, what is going to heat up and cool down faster? Land or water?

30. VII. Water Affects Temperature
31oF – 87oF
12oF – 101oF

31. Extend – Independent Practice
Fill out this graphic organizer in your notes with at least three facts for each property of water:
Properties of Water
Density
Adhesion
Cohesion
Maintains Temp.
Solubility

32. Option 2:
Working in groups of 2 each, students will create a brochure attempting to “sell” water using the following criteria:
You are visiting another planet as an alien. This planet has no water. You’re job is to sell water to the other planet by describing the different characteristics of water that make it able to support life. For each characteristic, you should have a picture and a caption that describes what it means and/or how it helps sustain life.
Option 1: 
Working independently, complete the following RAFT assignment:
Role: All life on earth
Audience: Water
Format: Love Letter
Topic: Why water makes life possible.
You will write a love letter to water explaining why it is essential for life. You will be instructed to include 4 of the 5 characteristics discussed when writing the letter. Letters should be at least 2-3 paragraphs in length. Once complete you will share their letter with others, and the entire group will choose one letter to share with the class

33. Exit Ticket Do exit ticket by yourself. No talking.
Talking/cheating = zero for class participation

34. Extend