Introduction
Plants are being studied by NASA for their potential ability to provide space vehicles or space stations with food, oxygen, and water while simultaneously acting as carbon dioxide filters. In this gas sensor activity you will examine the effects of human activity on the amount of oxygen in the air.

Note: When equipment setups are limited, it is appropriate to assign half of the class to experimentation teams and half to teams running the computer challenge, Living Off the Land - Which Plants Are Most Productive? (using the downloadable Plant Production Simulator). Each team will need at least two hours for lab and two hours for computer simulator activities. Combining these activities will help you to better understand the oxygen and carbon dioxide interrelationships between plants and humans. The Calculating Human Requirements activity will show you how different activities affect a person's daily caloric and oxygen intake and carbon dioxide output.