Observe the Geranium leaves to further investigate photosynthesis. Photosynthesis is the process that plants use to convert CO2 into carbohydrates (sugar), photosynthesis is also the metabolic process that literally feeds the world. The carbohydrates produced by photosynthesis are frequently initially stored (as starch) and are later used by the plant (or us) for food. The experiment below examines the requirement of light during photosynthesis. Watch for differences between the light-treated and the dark-treated leaves. Click the red button to start, click again to continue.