1. Title: Water’s Unique Properties Allow Life to Exist on Earth.

2. Water’s unique properties allow life to exist on Earth.
Water is a polar molecule.
Polar molecules have slightly charged regions because Oxygen doesn’t share electrons equally with Hydrogen.
Electrons have what kind of a charge
Label the charge on the water molecule below O
H H

3. Water’s unique properties allow life to exist on Earth.
Water is a polar molecule.
Polar molecules have slightly charged regions because Oxygen doesn’t share electrons equally with Hydrogen.
Electrons have what kind of a charge (negative)
Label the charge on the water molecule below O-
+H H+
What do opposite charges do?

4. Water’s unique properties allow life to exist on Earth.
Properties of Water
Water is a polar molecule
High specific heat capacity
High heat of vaporization
Adhesion
Cohesion
Three states of matter
Kinetic energy differences
Repels hydrophobic materials

5. Waters High Specific Heat Capacity
Water makes hydrogen bonds with other water molecules
You have to break the hydrogen bonds BEFORE waters temperature will increase
In other words, water absorbs a large amount of heat without changing temperature
Because of this water is very good at moderating climates of coastal ecosystems
Who has more extreme seasons, Chicago or Florida?
Water also helps maintain the correct temperatures in cells

6. Waters High Heat of Vaporization
Water molecules absorb energy (heat) as they change state from a liquid to a gas
Evaporative Cooling: when an area or body becomes cooler as water evaporates off of it
Sweating/ perspiring

7. Adhesion & Cohesion
Cohesion: water molecules are attracted to each other because of their polar charges
Responsible for surface tension (demo)
A “skin” that forms across the top of water
Adhesion: water molecules are attracted to other polar molecules and ions because of their charge distribution
Responsible for Capillary Action:
Water moves up thin tubes against gravity
Plants use this to get water from the roots all the way up

8. Water exists naturally in 3 states on Earth
Solid (ice)
Ice is less dense than liquid water
Ice floats and insulates bodies of water underneath
Liquid
Gas (water vapor)

9. Water is a Great Solvent
Water can dissolve other polar molecules
Water can dissolve ionic compounds (salt)

10. How Organisms Exploit Waters Properties
Water is a good medium for metabolic processes because of its solvent properties
Osmosis
Diffusion
Water can moderate temperature
Ice as an insulator
Evaporative cooling
Moderation of coastal climates
Capillary Action (in plants)
Surface tension
Transpiration