Toothpaste will turn universal indicator paper blue indicating a pH value of 9, which is a weak alkali. ... Litmus is an example of an indicator.

Drinking water must have a pH value of 6.5-8.5 to fall within EPA standards, and they further note that even within the acceptable pH range, slightly high- or low-pH water intake calculator can be ...

I must admit that I have not considered using litmus paper to determine general health. Human saliva has an alkaline pH, while stomach acid has an acid pH, so I am not quite sure what you would like ...

Litmus paper is usually purple in colour. When it comes in contact with a solution that’s acidic (pH of less than 4.5) it turns red. And blue, if the solution is alkaline (pH of more than 8.3).

Dr Yingfu Li, professor at McMaster University, and his team created a test for E. coli based on the Litmus test for pH. The test is a colorimetric sensor where existing Litmus dyes and pH papers ...