In this Activity, students use citric acid and baking soda to make "bath bubblers" similar to those sold in bath and body stores. They investigate the fizzing reaction that occurs when the bubblers are added to both cold and hot water. Bringing this real world product into the classroom adds interest and can lead to creativity, while introducing both acid/base concepts and rates of reaction. Further experiments can be performed using Alka-Seltzer tablets, which also contain citric acid and baking soda, and produce carbon dioxide when in contact with water.
Mary E. Harris and Barbara Walker, J. Chem. Educ. 2003, 80, p1416A.