Editorial use only.
Universal indicator paper being used to test the pH of three different solutions. Universal indicator paper changes its colour depending on the pH of the solution tested. It is used to measure the strength of an acid or an alkali. The Windex contains ammonia, a moderate alkali, which turns the universal indicator paper blue. The rubbing alcohol is a weak acid and turns the universal indicator paper yellow. The vinegar is a strong acid and turns the universal indicator paper red. Acid solutions have a high concentration of hydrogen ions, while alkali solutions have a low concentration of hydrogen ions.
Model release not required. Property release not required.