Materials

Bottle or container to hold water pH test kit OR pH paper Data Collection Student Worksheet (optional)

Background Information
pH measures the relative acidity of the water. A pH level of 7.0 is considered neutral. Pure water has a pH of 7.0. Water with a pH level less than 7.0 is considered to be acidic. The lower the pH, the more acidic the water. Water with a pH greater than 7.0 is considered to be basic or alkaline. The greater the pH, the greater its alkalinity. The pH of natural potable water should be between 6.5 and 8.5. Fresh water sources with a pH below 5.0 or above 9.5 may not be able to sustain plant or animal species.

Industries and motor vehicles emit nitrogen oxides and sulfur oxides into the environment. When these emissions combine with water vapor in the atmosphere, they form acids. These acids accumulate in the clouds and fall to earth as acid rain or acid snow. Acid rain damages trees, crops, and buildings. It can make lakes and rivers so acidic that fish and other aquatic organisms cannot survive.

NOTE: For more detailed information about pH, please consider using the Sense of Scale activity to learn what the pH scale is a representation of and about common products and their respective pH levels.

Test Procedure

Take the pH test kit out. Closely follow the instructions provided with the kit.   When collecting your water sample, here are some important guidelines: Try to take the water sample at a location away from the bank. Make sure you take a sample that is below the water surface.   Test the pH immediately. pH must be measured at the test site because changes in temperature affect pH value. NOTE: pH is recorded with a number value only; there are no units associated with the pH value.

What to Expect
Please note that this scale approximates what one could expect in a fresh water body.

pH Level	Water quality
Less than 5.5	Poor: Very Acidic fish and other organisms may find it impossible to survive
5.5 - 5.9	Fair
6.0 - 6.4	Good
6.5 - 7.5	Excellent
7.6 - 8.0	Good
8.1 - 8.5	Fair
Greater than 8.6	Poor: Very Alkaline fish and other organisms may find it impossible to survive

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