The woman in the foreground is a chemistry student and needs this grade to pass the class.  The experiment - finding the concentration of an acid using phenylalanine.  It should turn up purple and then slowly dissipate to the original color she thinks to herself.  With the stern and watchful eye of her professor looking onward, the student can't help but feel nervous in the presence of such a prestigious woman.  Drip, purple, fades to clear.  Repeat again and again until finally the purple turns to a pinkish state.  "The acid has a Ph level of 2.3," the girl states and receives an A on her exam.
