Raul Betancourt explains a recent experiment.

In this experiment, students react a base with its opposite — an acid — until it is neutralized. Students tested different type of antacids in order to figure out how much base each contains, and thus which would be the most effective!


The students can tell exactly when the base is neutralized with the help of a pH indicator, which changes from blue to yellow at that moment. If they know how many molecules of acid they added to neutralize the base, they can figure out how many base molecules were in the antacid to begin with. Watch this time lapse clip of students adding acid to a solution of yellow Tums, blue pH indicator and water. Green to begin with, the solution turns completely yellow as the students add more and more acid.

This is called titration, a technique often used to measure acid pH in pools, aquariums, water supplies and more.