Task: At this station, you will experiment with four solutions representing water collected in March 1995 from sources around New York State to determine their level of acidity.

Materials:

• Solution filled dropper bottles labeled A - D
• pH paper
• pH color chart
• Transparency test card
• Waste cup
• Paper towels
• Safety goggles
• Water for cleaning

Background:

The dropper bottles A through D contain samples that represent water collected in March 1995 from the following sources:

• Bottle A - Adirondack Lake water
• Bottle B - Finger Lake water
• Bottle C - Drinking (tap) water
• Bottle D - Great Lake water

Directions:

1. Put your safety goggles on. DO NOT taste or touch any solution. Clean up any spills immediately.
2. Place one drop of each solution on the transparency circle on the test card with the same letter as the solution.
3. Dip the end of a pH paper into solution A.
4. Compare the color of the pH paper with the chart on the pH color chart.
5. Record the pH of the solution on the data table on the answer sheet.
6. Repeat steps 3 through 5 for solutions B, C, and D using separate unused strips of pH paper for each solution.
7. Place used strips of pH paper in the waste cup.
8. Clean the transparency test cards with water. Throw any garbage into the waste cup.
9. Answer questions 1 through 4 on the answer sheet.

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   Answer Sheet
   Acid Precipitation
   1. Record the pH of each sample on the data table below.

      

   2. Using the data you have collected and the background information, determine the following:
      1. Which 1995 sample is most acidic? (If there is a tie, list them)

         ________________________________

      2. Which 1995 sample is least acidic? (If there is a tie, list them)

         ________________________________

      The pH of rain water in all of these areas was measured at 4.5 in 1993 and 3.0 in 1995.

   3. Compare your results on the data table from 1995 with the results from 1993.
      Which sample(s) was/were most affected by acid rain?

      _____________________________________

      In the space below, explain the reason for your answer.

      ________________________________________________________________________

      ________________________________________________________________________

      ________________________________________________________________________

      ________________________________________________________________________

   4. To survive, many organisms need the water pH to be between a pH of 5 and 9. The list below shows the lowest pH of water at which certain organisms can live.

      Bass	pH 5.0	Perch	pH 4.5	Snail	pH 6.0
      Minnow	pH 6.5			Salamander	pH 5.5

      Predict the order in which the organisms in a lake will die as a lake becomes more acidic.

      ________________________________________________________________________

      ________________________________________________________________________

   NYS Alternative Assessment in Science Project
   Copyright, April 1996
   The State University of New York
   The State Education Department
   Albany, New York 12234