When you breathe, the action is easy to see because your chest expands. When you exhale, you breathe out carbon dioxide. Exhale against a window and you can see the water vapor. How about plants? Do plants breathe? Well...not exactly. Plants take in carbon dioxide and produce oxygen through a passive process called respiration. This simple activity will provide your kid with visual proof that plants are producing the oxygen we need to survive.
What You Do:
- Find several plants that you can use for your experiment. Try to select a variety of plants such as a vine, a shrub or tree and an herb or flower. You can also choose a plant with red leaves vs green leaves or select plants with leaves of different sizes. Remember, you are not picking the plant or removing any of its leaves so choose something that you can slip a bag over without damaging the plant.
- Working with your first plant, place your bag over the plant, or a portion of the plant, and zip the bag as far closed as possible without damaging the plant. You won’t be able to close the bag completely, but that’s okay.
- Repeat Step 2 with several more plants.
- Come back in 20 or 30 minutes. What do you see? If you don’t see anything, wait for another 20 or 30 minutes. This step can take different lengths of time depending on the type of plant and the temperature outside. The droplets condensed inside the bag are water—evidence of the plant's respiration process!
Expand on this activity by repeating it at different times throughout the year. Do you get the same results in the fall? How about during the winter? In winter weather, many plants die while others go dormant. Does a dormant plant's respiration process still generate water vapor? Experiment to find the answer.