5.5 STORMY WEATHER
(Level: 7 : 8 : 10 acad : 10 appl : 12 acad :: Acid Deposition)

Purpose: To determine how acidic the precipitation is in your area and determine what are the likely causes.

What You Need: plastic collecting pan :: 3 small plastic bottles with tops :: pH testing kit :: weather maps from the local newspaper

Note: Do not use glass for collecting or holding samples.

What You Do:

1. Save the weather maps from the newspaper for the three or four days that precede the collection of the rain sample.
2. When it begins to rain or snow, place a clean plastic pan in a place where it will collect the precipitation directly.
3. Fill a clean plastic bottle with the precipitation. Cap it, and if you are doing this at home, place the bottle in the refrigerator.
4. As soon as possible, take the bottle to school and measure the pH of the precipitation.
5. Repeat steps 1 to 4 two more times over the next few weeks.
6. Examine the weather maps for 3 or 4 days prior to the collection of each sample. Try to determine the origin of the precipitation and the path it followed to your area.

Questions:

1. Record your findings in a data table with the following column headings: Date, pH of Sample, Origin of Precipitation, Path of Precipitation.
2. Account for the pH obtained in each case.>
3. Why was it necessary to keep the sample cold?
4. "Normal" precipitation (precipitation without acid input from human sources) has a pH of 5.6. Based on your results, how serious was the acid deposition problem during the period of your experiment?
5. What is "acid shock". What effect does it have on amphibian populations?

Note: Success from this experiment depends on weather conditions, therefore, an on-going study could be conducted.

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