MONDAY, OCTOBER 13TH, 2014

Bio.A.1.2.2: Describe the unique properties of water and how these properties support life on Earth

Objective: What makes water so important and unique?

Warmup: ***Brainstorm***

What properties do you remember about water? (ex. Freezing point, density, chemical

formula, etc)

Anything that you can remember…..

TUESDAY, OCTOBER 14TH, 2014

Bio.A.1.2.2: Describe the unique properties of water and how these properties support life on Earth

Objective: What makes water so important and unique?Warmup:

***Brainstorm***What properties do you remember about

water? (ex. Freezing point, density, chemical formula, etc)

Anything that you can remember…..

Period 1

THE UNIQUENESS OF WATER

HTTP://WWW.YOUTUBE.COM/WATCH?V=ASLUY2U1M-8

I. WHY IS WATER IMPORTANT TO ORGANISMS?

1. If you don’t live in it, you carry it with you: water makes up

60-95% of most organisms.

2. It plays many roles in the body:• Allows molecules & ions to move, collide and

dissolve• Decreases concentration in blood for easier

movement/better pH levels• Allows chemical reactions to occur• Maintains a constant body temperature

(homeostasis)

II. WHAT ABOUT WATER’S STRUCTURE ALLOWS IT TO DO ALL THIS?

1. Water is polar (exhibits polarity)• Polar molecule – molecule with an unequal

distribution of charge; each molecule has a negative (-) and positive (+) end.

II. WHAT ABOUT WATER’S STRUCTURE ALLOWS IT TO DO ALL THIS?

1. Water is polar (exhibits polarity)• Shape (^) of water indicates oxygen attracts

more e- than hydrogen; oxygen acts (-) and hydrogen acts (+)

• Water’s overall charge = 10 p+ 10 e- zero

• Polar molecules are very attractive because (+) and (-) ends function like a magnet

II. WHAT ABOUT WATER’S STRUCTURE ALLOWS IT TO DO ALL THIS?

1. Water is polar (exhibits polarity) - Because water is like a magnet:

• They (water molecules) attract:ions example: sodium (Na+) and

chloride (Cl-)polar molecules example: sugar

(carbohydrate)water

2. Water forms hydrogen bonds (bond between +/- ends of a

polar molecule)• Characteristics:

Weak bond – formed/broken easily

Part 1: Draw a model of one water

molecule. 1.) Show the number of protons,

neutrons and electrons in the shells of the atoms involved.

CUT OUT WATER MOLECULES

Part 2: Cut out a model of one water molecule. 1.) Color the oxygen atoms of each

water molecule red. 2.) Color hydrogen blue

3.) Indicate the relative charge of each side of the water molecule by placing a plus or a minus on the correct sides.

CUT OUT WATER MOLECULES

TUESDAY, OCTOBER 14TH, 2014

Bio.A.1.2.2: Describe the unique properties of water and how these properties support life on Earth

Objective: What makes water so important and unique?

Warmup: What does it mean when we say that water is POLAR?

Draw a picture or explain it please.

PART 3: On your cut-outs page:

1.) Color the oxygen atoms of each water molecule red.

2.) Color hydrogen atoms blue.

3.) Indicate the relative charge of each side of the water molecule by placing a plus or a minus on the correct sides.

4.) Cut out 5 molecules.

5.) Arrange them to show hydrogen bonds. Indicate the hydrogen bonds between each water molecule by drawing three black dots between them.

II. WHAT ABOUT WATER’S STRUCTURE ALLOWS IT TO DO ALL THIS?

2. Water forms hydrogen bonds (bond between +/- ends of a

polar molecule)• Characteristics:

Weak bond – formed/broken easily Responsible for cohesion – intermolecular

attraction between like molecules (example: H2O - H2O)

Produces surface tension so insects, leaves can float on water

Water molecules stick together to move against gravity (capillary action)

II. WHAT ABOUT WATER’S STRUCTURE ALLOWS IT TO DO ALL THIS?

2. Water forms hydrogen bonds (bond between +/- ends of a

polar molecule) Hold large molecules and H2O together.

Adhesion – the intermolecular attraction of unlike molecules

Water forms droplets on leaves Water molecules stick together to move

against gravity (capillary action)

II. WHAT ABOUT WATER’S STRUCTURE ALLOWS IT TO DO ALL THIS?

Like molecules

Unlike molecules

Water is “sticky”!

MINILAB – COHESION, ADHESION, SURFACE TENSION

III. WHAT OTHER PROPERTIES DOES WATER HAVE?

1. Has less density as a solid• Water forms crystal-like bonds when it freezes,

keeping the molecules at fixed distances from each other

• Low density – less tightly packed• Water expands when frozen and floats,

allowing organisms to live underneath

III. WHAT OTHER PROPERTIES DOES WATER HAVE?

2. Is a universal solvent• Dissolves many compounds such as

carbohydrates and some proteins• Allows chemical reactions to occur

III. WHAT OTHER PROPERTIES DOES WATER HAVE?

3. Has high heat of vaporization• Amount of heat energy needed to change 1 g of

100˚C boiling water to 100˚C steam(you sweat and water evaporates off

your skin to cool you)

III. WHAT OTHER PROPERTIES DOES WATER HAVE?

4. Has high specific heat• Amount of energy required to change 1 gram of

water by 1˚C(water resists change in temperature)

• Substances with H-bonds take longer to cool or heat than those w/o

• Allows organisms to maintain a stable internal environment (homeostasis)

• Allows water to resist temperature change

MORE ABOUT SOLUTIONS:

Water is known as the Universal Solvent: Solutions have 2 parts:

Solute – what is being dissolved Solvent – what is doing the dissolving

• NaCl Solution and dissolving

MORE ABOUT SOLUTIONS:

pH Scale – Measures the amount of hydrogen ions in a solution

Low