This interactive exposes students to Earth's atmospheric gases of oxygen, carbon dioxide, and ozone. As the user manipulates the interactive to increase or decrease the concentration of each gas, explanations and images are provided that explain and visualize what the Earth would be like in each scenario.

In this activity, students explore the role of combustion in the carbon cycle. They learn that carbon flows among reservoirs on Earth through processes such as respiration, photosynthesis, combustion, and decomposition, and that combustion of fossil fuels is causing an imbalance. This activity is one in a series of 9 activities.