Water Quality
by Nancy Rataj
Lesson I - The Water Cycle
Introduction: The water or hydrologic cycle on earth is a closed systeminvolving 3 processes - transpiration, evaporation and precipitation.
Objectives: Students will:
-identify evaporation
-identify transpiration
-understand the difference between transpiration and evaporation
-identify precipitation and some of its forms
Time: 3 part lesson ( 3-30 minute periods)
Terminology: transpiration, evaporation, precipitation , condensation, cycle
Materials:
-hydrologic poster
-2 pint jars and 1 lid
-2 gallon jars and 1 lid
-soil
-water
-gravel
-houseplants (2 sets)
-pot
-cover
-heat source for heating water
-teacher made worksheet on the water cycle
Procedure:
Day One: Students will observe evaporation by placing 2 jars, with identicalwater lines marked, on a sunny window sill. One jar is to be covered, oneis uncovered. This demonstration is best done on a Friday so a noticeabledifference can be observed in the next class (Monday). This activity canbe initiated with a discussion of where water does after a rainstorm.
Day Two: Students will observe precipitation in a simple experiment showinghow clouds release their moisture. Water will be heated in a covered potby the teacher till it boils. Water will be heated in a covered pot by theteacher till it boils. The heat will be turned off and the cover carefullylifted off. As the cover cools, the water vapor will condense on the lidand return to the pot in droplets.
Day Three: Students will observe over several days transpiration in plants.1-gallon jars filled with a layer of gravel, covered with 3 to 4 inchesof soil will be planted with 2 houseplants each. Water lightly, but equally,place on a sunny or bright window sill and cover one jar. Observe dailyfor one week. This is also best done on a Friday.
Assessment: Using the teacher-made worksheet, the students will correctlylabel 2 sources of transpiration, evaporation and precipitation.
Lesson II - Natural Water Sheds
Introduction: Students have seen how water is limited, how it is pollutedand how they can conserve. Many of these problems were created by man'sinterference with nature. This lesson will illustrate water waste (runoff)due to man's takeover and destruction of natural water sheds.
Objectives: Students will:
-recognize 3 different land surfaces and how they absorb precipitation
-rate these surfaces and their effectiveness to absorb precipitation.
Time: 2-30 minute periods
Terminology: absorb, absorption, water shed
Materials:
-3 1qt. waxed cardboard juice containers per student (one side of containerremoved)
-plaster of Paris
-soil
-sod
-sprinkling can with sprinkler head
-1 pt. measuring cup
-large dish pan (for catching run-off)
-teacher-made graphs
Procedure:
Day One: Discuss and review all we have covered too now. Use rest of thiscall to fill 1st container with teacher-prepared plaster of Paris (representinga paved surface) and to fill 2nd container with potting soil (representinga plowed or un-planted surface).
Day Two: Fill 3rd container with some soil and a pre-cut piece of sod tofit it ( representing a field or prairie).
Assessment: Students will then sprinkle each container separately (whileit sits in a dish pan) with 1 pint of "muddy" water. Studentswill then measure "run-off" from each container and graph resultswith their teams. Graphs will be turned in and taped to blackboard. Onechild from each group will rate each medium and class will discuss whatthey observed.
Lesson III - Pollution
Introduction: Since the water on earth is part of a closed system, it cannotbe lost or disappear. Pollution, however, destroys the usability of ourlimited fresh water.
Objectives: Students will:
-discover ways water becomes polluted
-identify common hazardous wastes
Time: 30 minute class, 10 minute follow-up lesson
Terminology: pollution, toxic, hazardous
Materials:
-2 copies of worksheet "Common Hazardous Wastes"
-3 glasses or small beakers
-water
-white vinegar
-salt
-magnifying glass
Procedure:
Students will observe what appears to be 3 glasses of water. Would theylike a drink? How do they know it is safe to drink? Students can come upwith ways to figure out which is the pure water ... smell, taste, closeinspection. Not all problems are easily recognizable - taste identifiessalt water, smell identifies vinegar. Most pollutants are invisible. Usemagnifying lens - can you see the difference?
Students will then go through work sheet as teacher reads the items, labelingonly those they feel would be toxic.
Class will then go through the list item by item and discuss how it couldget in our water supply.
Assessment: Several days later, students will go through their 2nd hazardouswaste worksheet, correctly identifying 80% of the toxic materials on it.
Worksheet:
Common Hazardous Wastes
1. transistor battery
2. car battery
3. shaving cream can
4. used motor oil
5. empty spray paint can
6. drain cleaner
7. empty insecticide spray can
8. unused matches
9. white cotton sheets
10. unused drugs and medications
11. unused fertilizer
12. broken thermometer (silver colored only)
13. rug spot remover
14. sand
15. flea killer collar for pets
16. newspaper
17. paper
18. used spray deodorant can
19. vinegar
20. flashlight battery
Lesson IV: Conservation
Introduction: Students have become aware that water should be conserved.They need to feel empowered that they can make a difference.
Objectives: The students will:
-arrive at 3 ways they can personally conserve
-arrive at 2 ways their families can conserve
-arrive at 1 way our community can conserve
Time: 30 minutes for discussion
Terminology: conserve, conservation
Materials: worksheet outlining 3, 2, 1 ways from above
Procedure:
Ask students if they feel we have a problem with water. Hopefully, a realizationof its limits will arise. Ways we waste water will lead them into how wecan conserve. Allow them time to come up with their own conservation ideas.
Assessment: Students have come up with 50% or more original ideas on howto conserve. The other ideas may have come from previous class discussion.