Has eating too much sour candy ever made your mouth sore? Have you opened your eyes underwater in a pool and felt the water burn your eyes? You're experiencing the effects of pH. pH is important in many aspects of daily life and science, from water purification to food preservation. STEM Programs Coordinator Lea Schram von Haupt explores how boiling a red cabbage can help you discover what substances around you are acidic or basic. Watch to see how cabbage juice turns a rainbow of colors.