In this lab activity, students use a chemical indicator (bromothymol blue) to detect the presence of carbon dioxide in animal and plant respiration and in the burning of fossil fuels and its absence in the products of plant photosynthesis. After completing the five parts of this activity, students compare the colors of the chemical indicator in each part and interpret the results in terms of the qualitative importance of carbon sinks and sources.

In this activity, students explore the way that human activities have changed the way that carbon is distributed in Earth's atmosphere, lithosphere, biosphere and hydrosphere.

This is a laboratory activity in which students will compare the amount of carbon dioxide in four different sources of gas and determine the carbon dioxide contribution from automobiles. They test ambient air, human exhalation, automobile exhaust, and nearly pure carbon dioxide from a vinegar/baking soda mixture.