Water Quality
by Bao Quach
Lesson I - The Hydrologic Cycle
(6 th gradeL.E.P. students. Duration: 40 min.)
Objective: The students will be able to understand water in nature circulatescontinually between the atmosphere and the surface of the earth accordingto a pattern called hydrologic cycle.
Materials:
-pan of very hot tap water
-pan of ice cubes
-paper and markers
Precautions: Do not touch the pans.
Activities:
-Where is water found on earth? In how many phases? Has its amount beenincreased or decreased since the creation?
-Class observes the vapor rise and condense into droplets.
-Why does wet cloth dry in the open-air? By what process? What factors influencethat process? Do they apply to natural phenomena?
-What is condensation? What factors influence consideration?
-In hot weather, people tend to stay apart from one another, and close toone another in cold weather. Now, each one will pretend being a water moleculemoving around in the classroom. How would you react to hot and cold temperaturesand to high or low atmospheric pressures?
-Make inferences to water's movement on earth.
-Explain the formation of underground water and the process of infiltration.
-What is the difference between perspiration (animal) and transpiration(plant)?
Evaluation:
-The teacher draws a chart of different landforms on the chalkboard. Bygroups of 3, the students copy the chart and jot down appropriate explanation.Report to class and post on classroom walls.
Extension:
-Class work: use several clear plastic cylindrical bottles of differentdiameters to study evaporation in function of contact surface, t , wind,atmospheric pressure, humidity. Graph the results.
-Construct a classroom terrarium with tight cover. Discuss the evaporationand transpiration processes. Weigh regularly this close system every day.
Lesson II - Precious Groundwater
(6th grade L.E.P. students. Duration: 40 min.)
Objectives: The students will understand:
-groundwater is clean and fresh
-it takes time for groundwater to renew.
Materials:
-clear plastic 2-liter pop containers cut at upper or lower to serve asfunnel and container
-top soil
-sand
-pea gravel
-peat moss
-waste water
Activities:
-Review water cycle: precipitation, surface water, percolation, groundwater
-With given materials, students by groups of 3 invent their most efficientfilters. Present work to class.
-What factors can possible influence the rate of filtration? What is porosity?
-Make generalizations and inferences to groundwater.
-In the western U.S. which has little surface water in lakes and rivers,on which sources of water must people depend?
-For what purposes is groundwater being used?
-If groundwater is used up faster than it is replaced, what do you thinkwould eventually happen to streams and lakes?
-Since the total amount of water available is limited and populations keepgrowing as well as their water needs, what do you think is the best wayto ensure the world's water supply?
-How can groundwater be polluted? What are the potential pollutants? Howcan we handle the problem?
Evaluation: Explain why ground water is clean and takes time to accumulate.Describe what is an aquifer.
Extension: Plan a field trip to a water reclamation plant. How to protecta well from being contaminated?
Lesson III - The Path of Your Tap Water
(6th grade L.E.P. students. Duration: 40 min.)
Objective: The students will be able to recognize household water followsa close cyclical path.
Materials:
-paper
-color pencils
-construction paper of different colors
-scissors
-scotch tape
-"From Sink to Stream" sheets
Activities:
-Describe the physical aspects of tap water before and after use.
-Can you itemize the amount of water you use everyday?
-Where do you think tap water comes from? Where does it end up after beingused?
-Draw a chart of your household water facilities with as much informationas possible about the pipes system. Explain orally to class.
-With cuts from construction paper, the teacher illustrates the flow-chartof a water plant and a water reclamation plant.
-The teacher introduces new words such as : intake, pre-treatment, mixing,coagulation, flocculation, chlorination, fluoridation, underground sanitarysewer pipes, street drain, storm sewer, primary, secondary treatment, sedimentation,sludge.
-Why is it important to treat wastewater before releasing it to the waterway?
-Can you enumerate some potential sources of contamination to water supplyin your area?
-Do you know how people get water for domestic use in rural areas of somedeveloping countries?
-Why do we need to save water?
Evaluation:
-Using blank sheets "From Sink to Stream", fill in different stepsin treating wastewater.
-Write a monologue of a drop of water from Lake Michigan traveling throughthe Chicago water system, bringing health to the households, carrying wastesthrough the sewage treatment plant before returning to the main waterways.
-What would you do to save water in your homes and at school?
Extensions:
-Visit the Chicago water system and the water reclamation plant.
-Compare and contrast sewage treatment plant and septic tank.
Lesson IV - Household Chemicals and Water Contamination
(7th grade L.E.P. students. Duration: 40 min.)
Objectives: The students will be able to:
-identify the harmful effects of household chemicals
-understand and follow label directions
-adopt responsible and appropriate disposal procedures
Materials: The students are encouraged to bring to class several labels,empty boxes or containers of their own household chemicals. They will alsohave to read in advance these labels. The teacher provides:
-magazines
-newspapers
-markers
-crayons
-glue
-charts of Chemical Hazards in the Garage and Workshop
-graph paper
Precautions: Apply safety measures for handling hazardous chemicals.
Activities:
-Divide class into groups of 4.
-Each group explains what their products are for, how to use them, whetherthey contain a hazardous substance, how to dispose them properly.
-Check label directions and compare with information available from theChemical Hazards chart.
-Place the products, or pictures cut from the newspapers into groups accordingto their usage's. Write down proper disposal directions.
-Each group writes on newsprint information about their products including:name of the product, possible hazards, disposal suggestions, precautionsand substitutes.
-From the groups of displayed products make a bar graph. Draw some conclusionsfrom the graph.
-Hang the graph and posters on the walls.
Evaluation:
-Describe how household chemicals can contaminate air, surface water orgroundwater.
-Name one of the most commonly used household chemicals How is it hazardous?How to dispose it properly? Is there any alternative to using this chemical?
Extension:
-Visit an industrial manufacture focusing on waste disposal regulation observances.
-Form a school Eco-team to enhance environment awareness.
Lesson V - Is Wetland a Wasteland?
Objectives: The students will be able to understand how a wetland works.
Materials:
-roasting pans
-modeling clay
-kitchen foam
-small pieces of indoor-outdoor carpeting
-sponges
-pine needles
-twigs
-grass
-weeds
-soil and other natural materials
-cotton swabs
-toothpicks
-glue
-scissors
-markers
-pictures of wetlands (plants and animals)
-jar of muddy and littered water
-water
-reference books
-film strips about wetlands
Activities:
-Has anyone of you ever been to a wetland here in the U.S. or back in yournative country? What did you observe there?
-Project film strips
-By groups of 4, the students follow instructions to create their modelsof wetlands and observe how it works. Report to class.
-Wetland controls flood: Fit the piece of carpeting into the wetland area.Pour some water on the land. Describe what happens. Now, remove the carpetingand water. Pour the same amount of water at the same spot and rate as before.Did you observe any difference? How do strong currents affect soil erosion?
-Wetland purifies water: Remove the water from the model and replace thecarpeting. Pour some muddy water onto the land. Compare the water that endsup in the body of water with the water in the jar. Now, remove water andcarpeting. Repeat the experiment. What happens without the wetland in place?
-Wetlands are important wildlife habitats, as well as important recreationsites for people. Explain why.
-Each group decorates its own model using foam instead of carpeting andfollowing descriptions in reference books.
Evaluation:
-Describe in writing different functions of a wetland. What happens whenwetland is destroyed?
Extension:
-Research about the case of the Everglades in southern Florida.
-Research about the economical value of the wetlands in Vietnam.
-Patterns of diseases and culture in the Dong Thap wetland in south Vietnam.