How Plants Make Food Activity

Objective: Explore how plants make food using materials from the air around them and the water in the soil and then use it to get energy.

Materials: Space for kinesthetic movement, props to identify water and carbon dioxide

Procedure:
Use all but six students to form a leaf by standing together in a circle, holding hands. Explain that they are going to be a leaf making food with the power of sunlight.

Have 3 of the students standing outside the leaf join hands as carbon dioxide, a gas found in the air which is a building block used by the plant leaf to make food. Have this carbon dioxide come inside the circle of the leaf.
Have 3 other students join hands as water that comes up from the roots into the leaf as the other building block to make food. Have this water come inside the circle of the leaf.

Photosynthesis: Now walk the carbon dioxide and water through making a simple sugar. Step inside the leaf yourself and say that you are the special chemical found in plants that can make food, the chemical called chlorophyll. Physically separate the students making up the carbon dioxide and the students making the water and recombine 5 of them into a simple sugar. This leaves 1 left over as oxygen that can be sent out of the leaf as a waste product. With more students this could be a balanced formula but at this age who cares?

Photosynthesis Summary: Carbon dioxide + Water + Sunlight = Sugar + Oxygen
or 6 CO2 + 6 H20 + Energy => C6H1206 + 6 02

Respiration: To use the food they have made, plants need to "burn" it in their cells just like animals to release the stored energy. During the day, they make so much oxygen that they can just use some of it and still have extra to get rid of. At night they take oxygen from their environment. Walk students through taking oxygen into the leaf and breaking the sugar into carbon dioxide and water again to get the energy.

Processing: Give students opportunity to master these ideas some way. Perhaps by making drawings, diagrams, writing a story, explaining it to others, etc.