The Effects of Acid on Bacteria Growth

The purpose of this experiment is to attempt to answer the query, “How does the presence of acid affect the growth of soil bacteria?”  The objectives of the researchers were to conduct as accurate an experiment as possible and to determine whether or not acid had a significant effect on bacteria growth.  To collect their data the researchers exposed Rhodococcus rhodochrous bacteria to acid at varying intervals over the course of two weeks and measured the growth of colonies.  The researchers randomized trials to eliminate bias, and used a two-sample t test to analyze their data.  This test finds a statistical value, t, which equates to a probability, p, which the results of an experiment are due to chance alone.  It was determined that acid had a statistically significant effect on the growth of bacteria, with populations decreasing rapidly as the amount of time exposed to acid increased.

Research Done By:

Scott Kallek
Fraser High School

D. C. Wheaton
Lakeview High School