what is an indicator for chemistry? How is this for a definition? Thanks
A susbtance that changes colour when added to a base or an acid. The colour it changes to will depend on which it is added to.
2 answers
it doesn't have to be an acid or base. Most of the medical test strips now (cancer, pregnancy, blood sugar level) use biochemical reactions to make a spot of color to indicate a change.
They are chemicals used in reaction so as to obtain a sharp endpoint