
Buffer Capacity of Three Local Water Sources
Medium
How much acid can a lake absorb before its pH changes? Some bodies of water resist changes in acidity better than others. This resistance is called buffer capacity.
You collect water samples from three local sources:
- Lake Murray
- the Saluda River
- Davis Pond
You measure each sample's pH with a test strip. Then you add one drop of hydrochloric acid (HCl) solution and check the pH again. The size of the pH shift shows how well each water source buffers against added acid.
A small pH change means strong buffer capacity. A large change means even a small amount of pollution could shift the water's chemistry.
Hypothesis
The hypothesis is that Lake Murray will have the least buffer capacity.
Method & Materials
You will collect water samples from three local bodies of water, test the pH level of the sample, and then add one drop of HCl solution to it with a dropper.
You will need a cup to scoop water, pH strips, a dropper, and HCl solution (warning: wear goggles and gloves when handling).
Results
The results showed that Lake Murray had the least buffer capacity, indicating that it is the most vulnerable to pollution.
Why do this project?
This science project is interesting and unique because it allows us to measure the buffer capacity of local bodies of water and see how much pollution they can take before they become unsafe.
Also Consider
Experiment variations to consider include testing different water sources and testing different amounts of HCl solution.
Full project details
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