Plants use the energy in the sun’s rays to make food. The sun is a renewable source of energy. The chemical energy in plants gets passed on to animals and people as they eat them. When plants synthesize food they use carbon dioxide and water. The process of synthesizing carbohydrates with the aid of the energy in light is known as photosynthesis. The carbohydrates plants make are used by plants and animals as a source of energy.
In this demonstration, stored energy in plants is made visible by a simple procedure. The demonstrator chops up spinach, extracts the chlorophyll in the leaves with ethanol, isolates it in a test tube and shines a black light on the green chlorophyll causing it to glow blood red. The red light represents the energy stored in plants and in fossil fuels—a vivid reminder that energy found in nonrenewable resources such as fossil fuels originally came from the sun.