In this Activity, students make a water filtration column using a 2-liter plastic beverage bottle that contains layers of gravel, sand, and activated charcoal. They prepare a contaminated sample of water and examine the filtration ability of the column. This environmental chemistry Activity can be used to complement a celebration of Earth Day. It can be used in a discussion of water quality, pollution, and the treatments water undergoes before it reaches the faucet. It can also be extended to include discussions about commercially available water filters, such as Brita.
Erica K. Jacobsen, J. Chem. Educ. 2004, 81, p224A.