Extension Ideas
An alert reader has noted that this lesson is over-simplified for children. Note that “This is not a conclusive experiment to show that plants require light. Covering the bottom of the leaf may prevent carbon dioxide from entering the leaf stomata, which will prevent photosynthesis even with adequate light.” Putting the entire plant in a dark closet would be a more definitive experiment.
Some may be interested in learning more about chlorophyll and photosynthesis. Encourage them to do some research and gather information to share with others. The article “Avoid Misconceptions when Teaching about Plants,” by the reader referred to above, is a detailed and comprehensive source.
Another fun and easy experiment is to take a shoe box or other cardboard box cover and put it on top of a very green grassy area. Put a rock on top of the box so it stays put. Every day for a week, take a quick peek to see what is happening to the grass under the box. After a week, look at the grass and see if there are similarities between it and the leaves we experimented with. Watch the grass for another week to see if it turns green again and how quickly it happens.