1. Water: Our most important resource Milbank High School

2. Discussion What are some of the uses of water? What are some of the uses of water? What are some ways we are hurting our water supply? What are some ways we are hurting our water supply? How can we improve the water that we have now? How can we improve the water that we have now?

3. Importance of Water Constitutes 2/3rds of the mass of most organisms Constitutes 2/3rds of the mass of most organisms 75% of the Earth’s surface 75% of the Earth’s surface

4. Importance of Water Con’t PropertyMeaningImportance Universal Solvent Comps. Dissolve in water Dissolved Comps. can be brought to cells Transparency Light passes through Light reaches cells in plants in water Cohesion (surface tension) Water molecules stick together Small animals walk on water, water can be pulled to the top of trees

5. Importance of Water Con’t Heat Capacity Large amount of energy needed to raise the temp Water bodies have stable temperatures Density of Ice Ice is less dense than water so it floats Water rarely boils in nature Evaporation Requires a lot of energy Cools warm cells

6. Structure H 2 O (compound) H 2 O (compound) Composed of two elements (hydrogen and oxygen) Composed of two elements (hydrogen and oxygen) –Two hydrogen atoms and one oxygen atom Composed of hydrogen and oxygen atoms Composed of hydrogen and oxygen atoms H 2 O is waters Chemical Formula H 2 O is waters Chemical Formula

7. H H O H H O H H O H H O H H O H H O H H O H H O H H O H H O H H O H H O LiquidSolid

8. Contamination Ground water contamination (aquifers) Ground water contamination (aquifers) River water River water Lakes Lakes Oceans Oceans

9. Area Water How are area residents hurting our local water supply? How are area residents hurting our local water supply? Are there any naturally occurring instances in which water quality is hurt? Are there any naturally occurring instances in which water quality is hurt?

10. What makes water unique? High Surface Tension High Surface Tension Volume change when frozen Volume change when frozen Ability to change states Ability to change states

11. Water: Acid or Base? pH Values pH Values Pure Water: a perfect 7 Pure Water: a perfect 7 Acids: below a 7 Acids: below a 7 –What are some acids? Bases: above a 7 Bases: above a 7 –What are some bases?

12. Summary Water is our most important resource…? Water is our most important resource…? Water has many unique properties Water has many unique properties –Specific heat –Surface tension –Universal solvent –Transparent Sources of contamination Sources of contamination