(A) Making An Indicator- to test pH of pond water, soil, and rainwater samples
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MATERIALS NEEDED: red cabbage leaves, a heat source, water, 250 ml beaker
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PROCEDURES: (1) Boil several red cabbage leaves in water until the mixture turns dark red. (2) Let the mixture cool for about 1 hour or let set for the remainder of the day.
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RESULTS: (1) What is the purpose of the indicator?
(B) Determining the pH of Pond Water and Rain Water Samples
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MATERIALS NEEDED: jars or beakers, indicator (see above procedure to make indicator), samples of pond water collected from different ponds, samples of rain water collected over a period of time
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PROCEDURES: (1) Assign students to collect pond water samples from different places in their community. Also tell students to collect and date rainwater samples whenever it rains. (2) Place 25ml of each sample in a labled beaker. (3) Test the rainwater and pond water samples with your indicator. (4) Record your results on a chart stating the color of the samples after adding two ml of indicator to your samples. (5) Use a ph chart to record the pH of each sample.
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RESULTS: (1) What is the pH of your rain water samples? (2) How does the pH of your rainwater compare to that of normal rainwater (pH 5.6)? (3) Give some possible reasons why your think your rainwater is or is not very acidic. (4) What is the pH of your pond water samples? (5) How does the pH of your pond water sample compare to that of a healthy pond? (6) Do you think that the pond water sample is too acidic, why?
(C) Testing the pH of Soil Samples:
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MATERIALS NEEDED: funnel, beaker, soil sample, water, heat source
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PROCEDURES: (1) Place filter paper in a funnel and fill the funnel with your soil samples. (2) Hold the end of the funnel over a small beaker and pour 100 ml of boiled distilled water through the soil; dirty water will collect in the beaker. (3) Place about 20 ml of indicator into the water sample and stir. Record the color change of the sample on a chart for each sample taken. (4) Determine and record the pH of the collected water from the siol sample.
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RESULTS: (1) What is the pH of the soil samples? (2) Consider the data on the pH of the rainwater of your area. In what way, if any, is this rainwater affecting the acidity of your soil?