1. Water & Transpiration or Water, water everywhere and all the boards did shrink. Water, water everywhere and not a drop to drink. J.G. Mexal A/H 100

4. Middle Rio Grande Surface Water Budget /Alb.J. 1999

5. Water & Transpiration Irrigation & Water Management Big Water Users/ Alb. J. 9/17/96 –City Parks4.7 KK L/day –Tanoan G.C.2.8 –Arroyo del Oso G.C.2.6 –Ladera G.C.2.3 –UNM2.2 + 7.2(private) –Los Altos G.C.1.9 –NMSU6.8

6. The Mystery and The Magic! Trees can ‘pull’ water up from the soil through the bole of the tree into the leaves and out into the atmosphere. In some cases, this is a distance of over 300 ft! How do they do that????

7. Water is truly magical! Molecule –Hydrogen (H 2 ) –Methane (CH 4 ) –Water (H 2 O) –Nitrogen (N 2 ) –Ethane (CH 3 -CH 3 ) –Oxygen (O 2 ) –Carbon Dioxide (CO 2 ) –Propane (CH 3 -CH 2- CH 3 ) Molecular Weight –2 –16 –18 –28 –30 –32 –44 Which one of these is different?

8. Water is truly magical! Molecule –Hydrogen (H 2 ) –Methane (CH 4 ) –Water (H 2 O) –Nitrogen (N 2 ) –Ethane (CH 3 -CH 3 ) –Oxygen (O 2 ) –Carbon Dioxide (CO 2 ) –Propane (CH 3 -CH 2- CH 3 ) Molecular Weight –2 –16 –18 –28 –30 –32 –44 Which one of these is different? Water is a liquid at room temperature!

9. Hydrogen Bonding http://www.lsbu.ac.uk/water/molecule.html http:// www.biology.arizona.edu/biochemistry/tutorials/chemistry/page3.html Hydrogen weakly bonds to Oxygen, Nitrogen, and Fluorine (you can ignore this one)

10. Chemistry for Aggies—Water Properties Water is a liquid at room temperature Water freezes at 0 o C (32 o F) –Technically this is not true: water actually freezes at about -3 to -8 o C, and ‘bounces’ up to 0 o C –Water and ice can exist only at 0 o C –Freezing point reduced by the addition of other molecules –Gives off energy (heat) Water boils at 100 o C (212 o F) –Boiling point increased by the addition of other molecules –Required input of energy (heat)

11. Chemistry for Aggies—Water Properties Water is the ‘Universal Solvent’ –Transports ions (Ca ++, K +, NH 4 +, H2PO 4 - ) in transpiration stream –Transports organic compounds (carbohydrates, amino acids) –Maintains complex organic compounds in solution (DNA, proteins)

12. Chemistry for Aggies—Water Properties Have you ever used a straw to drink? Cohesion: Water molecules stick to each other because of hydrogen bonding. –This allows the giant redwoods to pull water up through the transpiration stream. –This gives ice its structure.

13. Chemistry for Aggies—Water Properties Have you ever blotted up a spill with a paper napkin? Adhesion: Water molecules stick to other molecules because of hydrogen bonding and the polar nature of the molecule. http:// www.biology.arizona.edu/biochemistry/tutorials/chemistry/page3.html

14. Water & Transpiration Colligative Properties of Water Adhesive Properties

15. Water & Transpiration Colligative Properties of Water Boiling Point and Freezing Point of Water Pure H 2 0 1 Molal Sol’n* Boiling point100100.52 O C Freezing point 0 - 1.86 O C Osmotic pressure 0 - 2.27 MPa Water potential 0 - 2.27 MPa 1 Avogadro’s number = 6 X 10 23 molecules

16. Have you ever made ice cream? Heat of fusion: When water changes to ice, 80 cal/g of heat is given off. Hydrogen bonding of waterHydrogen bonding of ice http:// www.biology.arizona.edu/biochemistry/tutorials/chemistry/page3.html Chemistry for Aggies—Water Properties

17. Have you ever made ice cream? Heat of fusion: When water changes to ice, 80 cal/g of heat is given off. Hydrogen bonding of waterHydrogen bonding of ice http:// www.biology.arizona.edu/biochemistry/tutorials/chemistry/page3.html Chemistry for Aggies—Water Properties Ice is less dense than water

18. Water & Transpiration Colligative Properties of Water Cohesive Properties

19. Chemistry for Aggies—Water Properties Colligative Properties of Water –Freezing Point of Water Pure water freezes at 0 o C Molal solution freezes at -1.86 o C Phase change requires 6 kJ/mol –Boiling Point of Water Pure water boils at 100 o C Molal solution boils at 100.52 o C Phase change requires 41 kJ/mol Most plant can tolerate exposure to ~-2 o C

20. Chemistry for Aggies—Water Properties Have you ever made ice cream? Heat of fusion: When water changes to ice, 80 cal/g (6 kJ/mol) of heat is given off. Pure water and ice can only exist at one temperature (0 o C or 32 o F)—frost protection in the Fall Adding salt reduces the freezing point [this is why milk+sugar+strawberries does not freeze at 0 o C and why leaves do not freeze at 0 o C] Water changing to ice gives up heat

21. Chemistry for Aggies—Water Properties Colligative Properties of Water –Freezing Point of Water Pure water freezes at 0 o C Molal solution freezes at -1.86 o C Phase change requires 6 kJ/mol –Boiling Point of Water Pure water boils at 100 o C Molal solution boils at 100.52 o C Phase change requires 41 kJ/mol [Vaporization] Water changing to vapor absorbs heat

22. Chemistry for Aggies—Water Properties Have you ever used a swamp cooler? Heat of vaporization: when water changes to vapor, 540 cal/g is removed. –Leaves are ~10 o C cooler than ambient air because of transpiration –Misting buds in the Spring can delay heat accumulation (GDD) and thus bud break– providing frost protection in the Spring.

23. Infrared Surface Temperature Influenced by Surface Cover Military Time (hr) Temperature ( o F)

24. Infrared Surface Temperature of Artificial Turf Influenced by Irrigation Military Time (hr) Temperature ( o F)