History 5000-6000 yr B.P.

1. History 5000-6000 yr B.P. Hydraulic engineers build canals, levees, dams, water conduits, and wells along the Indus in Pakistan, the Tigris and Euphrates in Mesopotamia, the Hwanf Ho in China, and Nile in Egypt. 3800 B.P. 3000 B.P. Evidence of Hydrological cycle recognition as early as 3000 B.P. 2400 B.P. Much of the early understanding was based on Greek philosophers musings which were a little off the marks, especially for underground mechanisms These notes are provided to help you pay attention IN class. If I notice poor attendance, fewer notes will begin to appear on these pages

2. late 100's B.C. Vetruvious first recognized that ground water is from rain and snow infiltration and not upwelling from deep subterrain 1500-1550 AD Leonardo Da Vinci and Bernard Palissy both assert that water in rivers comes from precipitation...initiation of modern scientific approach tot he hydrologic cycle 1700 AD ~1750 AD Use of the word “hydrology” in approximately it’s current meaning began pre-1800 These notes are provided to help you pay attention IN class. If I notice poor attendance, fewer notes will begin to appear on these pages

3. 1856 - Up to this time, little recognition of ground water flow. Henry Darcy establishes the basic law of flow through a porous material 1800's – 1922 - Section of Scientific Hydrology established in the International Union of Geogesy and Geophysics 1930 – Future Hydrology/hydrogeology will become very important as population grows and demand for water increases (some estimates of water demand doubling in next 20 years) These notes are provided to help you pay attention IN class. If I notice poor attendance, fewer notes will begin to appear on these pages

4. Hydrology - Study of water (occurrence, distribution, movement, and chemistry) • Hydrogeology - • Both descriptive and analytic. These notes are provided to help you pay attention IN class. If I notice poor attendance, fewer notes will begin to appear on these pages

5. Water Properties Covalent bonds - attractive forces between atoms that hold molecules together. Each atom retains its electrons but shares them with adjacent atoms. When separated, each retains its own electrons Ionic bonds – Van de Waals forces - very weak electrostatic attraction between molecules Hydrogen bonds – Net charge of molecule is zero, but it has a positive and a negative side. This is called a “polar molecule” These notes are provided to help you pay attention IN class. If I notice poor attendance, fewer notes will begin to appear on these pages

6. Energy required to break bonds in 18 g of water Covalent bonds: 100's to thousands of kiloJoules Ionic bonds: hydrogen bonds: 18.7 kJ van der Waals bonds: hydrogen bonding affects the structures of ice and water, given them many unique properties. Water molecules in ice are held together in a crystal lattice to form six-sided puckered rings arranged in layers. These notes are provided to help you pay attention IN class. If I notice poor attendance, fewer notes will begin to appear on these pages

7. WHICH IS ICE? WHICH IS WATER? ICE WATER These notes are provided to help you pay attention IN class. If I notice poor attendance, fewer notes will begin to appear on these pages

8. These notes are provided to help you pay attention IN class. If I notice poor attendance, fewer notes will begin to appear on these pages

9. WATER…THE MIRICLE SUBSTANCE Colorless, tastelesss, and odorless Freezing Point of water is? Boiling Point of water is? ______ is unique in that it is the only natural substance that is found in all three states -- liquid, solid (ice), and gas (steam/vapor) Heat Capacity is the highest of all solids and liquids except? - prevents extreme ranges in water temperature Latent heat of fusion is the highest of all substances, except? - These notes are provided to help you pay attention IN class. If I notice poor attendance, fewer notes will begin to appear on these pages

10. Average ocean salinity is about 35 ppt These notes are provided to help you pay attention IN class. If I notice poor attendance, fewer notes will begin to appear on these pages

11. Latent heat of evaporation is ___________ of all substances -important in heat and water transfers to the atmosphere Thermal expansion: temperature of maximum density decreases with increasing salinity. Temperature of maximum density for pure water is? Water is unusual in that less dense as a solid than liquid density of ice Ih is , but varies with gas content These notes are provided to help you pay attention IN class. If I notice poor attendance, fewer notes will begin to appear on these pages

12. Surface tension is highest of all liquids, except? -important for capillary action Dissolving power: dissolves more substances and in greater quantities than any other liquid Critical ingredient for life on this planet (and others) Were it not for the solvent property of water, life could not exist because water transfers nutrients vital to life in animals and plants. “Where there is water there is life” These notes are provided to help you pay attention IN class. If I notice poor attendance, fewer notes will begin to appear on these pages

13. These notes are provided to help you pay attention IN class. If I notice poor attendance, fewer notes will begin to appear on these pages