We tested six solutions including :Sea water, soapy water, hepar, acetic acid, tap water and distilled watter.
We did four experiments.
The first experiment with "cresol red " and our results were:
Sea water we see a yellow precipitate.
Soapy water we see a green precipitate.
Hepar we see a red precipitate.
Acetic acid we see a yellow precipitate.
Tap water we see a yellow precipitate.
Distilled watter we see a green precipitate.
When the precipitate is red the solution is also basic or acid and when the precipitate is yellow the solution is neutral.
After we conduct an experiment with pH meter:
Soapy water we see 7.81
Hepar we see 7.82
Acetic acid we see 2.8
Tap water we see 4.53
Distilled watter we see 4.64
We note that the second experiment were more precise than the first experiment.