ShareForce, Energy, & Motion - The Case of the Disappearing Chlorophyll!
When you eat foods, your body gains energy from the food. If you are eating food that came from a plant, the energy in that food came from the plant. Have you even wondered where do plants get their food for their energy? Plants use energy from the sun to make their own food.
Earlier you learned that plants use the proces called photosynthesis to convert light energy into chemical energy. Recall that the process of photosynthesis was written chemically as:
As shown in the equation above, plants have three requirements to make their food: light, carbon dioxide, and water. The process occurs in small parts of plant cells that contain chlorophyll. In the following activity, you can demonstrate how plants respond to changes in the amount of light energy.
The leaves from a plant left in the dark have little or no starch compared with leaves from a plant that has been in bright light.
Materials:
- Black construction paper
- Scissors
- Two paper clips
- Leaves on a living plant (hint: this works best if the leaves generally are un full sunlight.)
Procedure:
- Cut out any geometric shape from a piece of paper.
- Paperclip the shape to a green leaf.
- Do not remove the leaf from the plant.
- Leave the leaf alone for at least one week
- Return to your leaf and observe what has happened.
- You may remove the leaf from the tree at this point to make further observations.
Safety concerns: As with all science lab activities, the most important safety rule is to follow all teacher directions.
Analysis:
- What changes did you observe in the leaf that was covered by the paper?
- Why do you think these changes happened?
- Is there chlorophyll still under the leaf area that was covered by paper?
- Did photosynthesis occur under the paper?
