1. LIFE DEPENDS ON THE UNIQUE PROPERITIES OF WATER

2. Physical Properties- can be observed and measured
Water is a form of matter
Matter- anything that occupies space and has mass

4. What happens when you put an ice cube in a glass of water?
Why????
What do you think would happen to a can of coke and diet coke if we placed it into a container of water? Float? Sink? Why?

5. THE STRUCTURE OF WATER
Made up of two covalently bonded hydrogen atoms to an oxygen atom
Polar Molecule- a molecule that has opposite ends with opposite charges

6. THE STRUCTURE OF WATER
Hydrogen Bond- weak attraction, bond between a hydrogen atom of a molecule and a slightly negative atom within another molecule.

7. WATER’S LIFE SUPPORTING PROPERTIES
Cohesion
Adhesion
Temperature Moderation
Low Density of Ice
Water’s Ability to Dissolve Other Substances

8. COHESION AND ADHESION
Cohesion- the tendency of molecules of the same kind to stick to one another
Adhesion- an attraction between unlike molecules

9. COHESION AND ADHESION Example: water transport of trees/plants
Evaporation pulls water which are attached by cohesion up from the roots.
Adhesion of water to the walls of veins resist the downward pull of gravity

11. Drops On a Penny How many drops fit on the penny?
Explain the bubble that forms on penny

12. COHESION AND ADHESION
Surface Tension- cohesion which pulls the molecules at the surface tightly together

13. When have you experienced surface tension?

14. Basilisk Lizard http://www.youtube.com/watch?v=45yabrnryXk&feature=fvw

15. TEMPERATURE MODERATION
Thermal Energy- total amount of energy associated with the random movement of atoms and molecules in a sample of matter.
Temperature- a measure of energy of random motion of particles in a substance

16. TEMPERATURE MODERATION
When two substances differ in temperature, thermal energy in the form of heat is transferred from the warmer substance to the cooler one

17. TEMPERATURE MODERATION
When you heat molecules move faster
When you cool molecules move slower
Water takes more energy to heat because of hydrogen bonds
Water retain heat longer because of hydrogen bonds

18. LOW DENSITY OF ICE Density- amount of matter in a given volume
In most substances the solid state is more dense than the liquid state

19. LOW DENSITY OF ICE
Water’s solid state is LESS dense than the liquid state
WHY?????
Hydrogen bonds in ice (solid) keep molecules spaced out

20. LOW DENSITY OF ICE Since ice is less dense than water it floats
Ice prevents oceans from freezing over
Ice insulates the liquid water below allowing life to persist

21. WATER’S ABILITY TO DISSOLVE OTHER SUBSTANCES
Solution- a uniform mixture of two or more substances
Solvent- the substance that dissolves the other substance and is present in greater amounts (water)
Solute- the substance that is dissolved, present in a lesser amount (salt)

22. WATER’S ABILITY TO DISSOLVE OTHER SUBSTANCES
Aqueous Solution- when water is the solvent
Water molecules surround ions and break them apart

23. WATER’S ABILITY TO DISSOLVE OTHER SUBSTANCES
Water is the “Universal Solvent”
Water is the main solvent inside all cells, blood, and plant sap

24. Wrap Up! Structure of Water Molecule = Bent. Why?
Structure of Water Molecule = Bent. Why?
5 Unique Properties of Water:
1. Cohesion
2. Adhesion
3. Temperature Moderation
4. Low Density of Ice
5. Water’s Ability to Dissolve other Substances

25. Exit Slip
1. Explain how the structure of water molecules results in attractions among them.
2. Give an example of how cohesion among water molecules is important to living things.
3. Explain one way in which water can moderate temperature.