How Fast Can a Carrot Rot?
Everyone knows carrots are good for you, but they are also good for experiments about decomposition by soil microbes.Copyright U.S. Centers for Disease Control
Students conduct experiments to determine what environmental factors favor decomposition by soil microbes. They use chunks of carrots for the materials to be decomposed, and their experiments are carried out in plastic bags filled with dirt. Every few days students remove the carrots from the dirt and weigh them. Depending on the experimental conditions, after a few weeks most of the carrots have decomposed completely.
Engineers must understand what causes vegetables to decompose in order to develop methods for transporting and preserving them from the fields to grocery stores. Additionally, engineers design waste treatment systems that use microbes to break down waste.
After this activity, students should be able to:
- Describe a controlled experiment that tests for the effects of a physical feature of the environment, such as temperature or moisture level, on the rate of decomposition by soil microbes.
- Describe some of the physical conditions that are favorable or unfavorable to microbial decomposers.