My 7 year old nephew is currently doing a science project for school; "Do common household substances change the Ph of water?"

He has asked for my help and I don't know the answers, so could anyone help with the following please?

Our tap water has fluoride added to it. Will this affect his experiment in any way? Should he used bottle water instead?

Also, he is going to use vinegar, salt, baking soda and bleach. Any suggestions for other substances?

Fluoride won't have a significant effect on the pH of the water. I would just use tap water, but, if you want to get as close to pure water as you can, use distilled water (not spring water, filtered water, or mineral water).

If you have any ammonia, I would recommend trying that in addition to the things you mentioned.



As a sidenote, the pH of any water you use is unlikely to be 7 (neutral) to start out.
Water is normally slightly acidic due to dissolved carbon dioxide.
CO₂ + H₂O < - > H₂CO₃ < - > H+ + HCO₃-
Other things in your water can change this, however. For example, if you live in an area with a lot of limestone (CaCO₃), however, the solution will be less acidic or even slightly basic.
Ca(2+) + CO₃(2-) +H₂O < - > Ca(2+) + HCO₃- + OH-

[This message was edited by Karrow on 04-18-03 at 06:29 PM.]