Introduction

Organisms are often very sensitive to the effect of acids and bases in their environment. They need to maintain a stable internal pH in order to survive—even in the event of environmental changes. Many naturally occurring biological, geological, and man-made chemicals are capable of stabilizing the environment’s pH. This may allow organisms to better survive in diverse environments found throughout the earth. Teams will work in pairs, using one computer and two pH systems. One team will measure the effect of acid on biological materials, while the other team will measure the effect of base on biological materials. Each group will test the biological materials assigned to them, and all groups will share their data at the end of the class.

Objectives

In this experiment, you will

  • Add an acid to a material and note the extent that it resists changes in pH.
  • Add a base to a material and note the extent that it resists changes in pH.
  • Work with classmates to compare the ability of different materials to resist pH changes.