Grades 6-8. A Carolina Exclusive! Astonish and engage students with Alka-Seltzer(r) and milk of magnesia chemical rainbow demonstrations. Through measuring the pH of 10 common household substances with litmus paper, pH test strips, and universal indicator, students learn about pH and when to use each pH measurement tool. After they explore pH, challenge them to explain the 2 demonstrations. Instructions included. Supports 10 groups.