Testing the pH of Stream Water

27 Jul

testing pH cabbage juiceThis week we tested the stream water for pH using cabbage juice. Before the program I prepared the cabbage juice indicator and made up the standards for the pH testing using various acidic and basic solutions. I used this basic definition for pH: a scale that measures how acidic or basic a solution is; measuring hydrogen ions in a water based solution.

On a more practical level, we tested the water so the kids know that if you leave a salamander or tadpole in water that is not changed frequently or properly filtered it becomes poison for the animal.
stream water pH

This these were are standards:

bright pink: acidic
light pink: acidic (less)
purple: neutral
blue green: basic
clear: basic (more)

These were the solutions we tested: lemon juice, ammonia (dilute), stream water, tap water, vinegar
The kids were scientists as they took some water samples and tested various solutions including the steam water to visually compare the color to the standards. Surprisingly we found the stream water to be a bit acidic.

Then they had fun using the pipettes and exploring mixing colors.

ph testing 2ph testing 3ph testing 4ph testing 1


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