1. 6.12 – NOTES Water

2. 2 water related challenges faced every day-
Can we get enough water?
Is the water pure enough?

3. Purity is a relative term
100% pure water is impossible in a municipal system
Cost – very expensive to remove everything
Dissolved Gases – gases dissolve very easily and are hard to get out
What are some other impurities that may be found in water?
Disinfecting agents, mud, trash, skin, algae, fish, sticks

4. It takes approximately 120 L of water to produce one 1
It takes approximately 120 L of water to produce one 1.3 L can of fruit juice. It takes about 450 L of water to place one fried egg on your breakfast plate. Think of possible explanations for these two facts.
Direct vs Indirect uses of water
Direct – measureable
Indirect – Can’t Measure

5. How do we purify water?
Filtration
Process of separating solid particles from a liquid by using a membrane
Filtrate
Liquid left after filtration; residue = solid particles
Adsorption
Attraction of impurities to the surface of something ; charcoal absorbs odor and color
Percent recovery
% of purified water recovered at the end of the purifying process
% recovery = final volume
initial volume x 100

6. Pure and Impure Water
Why is it useless to get water that is 100% pure?
Very expensive
It’s hard to remove trace amounts of metals and other ions from water

7. Water Supply and Demand
15 trillion L (4 trillion gallons) of precipitation falls in the US each day
10 % of this is used by humans

8. Average family of 4 uses 1200 L of water/day
Direct use only
Use that can be directly measured
Indirect use - can’t be directly measured
We are generally unaware of how much water we actually use each day
Anecdote about my water situation

9. Where is the World's Water?
Water is unusual due to the fact that it exists as all 3 states (solid, liquid, gas) at normal conditions
Most of the US has abundant supplies of water
Surface water- water that is exposed to the atmosphere, rivers, lakes, streams, oceans, etc

10. Groundwater- must be pumped to the surface to be used; in wells
 1/5 of all water is groundwater
Aquifer- water holding layer of rock, sand, or gravel that is a holding are for groundwater

11. The majority of water must be purified before being used
Picks up dissolved gas, rocks, soil as it travels through the ground/pipes
Where is it?
97.2%- oceans
2.8%- freshwater
2.11%- glaciers/ice caps
0.62%- groundwater
0.009%- lakes
0.001%- atmospheric moisture
0.0001%- rivers