Experiment: Access to Air

Materials (for each group of 3-4 people)

1. A plant (either indoors or outdoors). Good plants for this experiment include: philodendron, ficus, magnolia, citrus trees. Note: do not pick the leaves! Use leaves that are still attached to the plant for this experiment
2. 6 small plastic bags (sandwich size is good) and twist-ties or rubber bands (ziplock alone will not provide enough of a seal)
3. Experiment Log (provided)
4. Pen or pencil
5. Petroleum jelly
6. Measuring cups or spoons

Steps

1. Label three plastic bags with the word “air” and three plastic bags with the words “no air”.
2. Place each bag labeled “air” over a leaf on the plant and tie the base securely.
3. Select three additional leaves on the plant. Cover both surfaces of the leaves. with petroleum jelly.  Place the bags labeled “no air” over the leaves and tie the base securely.
4. Place the plants outside in full sun or on a very sunny windowsill.
5. Record your hypothesis on the Experiment Log.
6. After 24 hours (1 day), remove one bag labeled “air” and one bag labeled “no air.” Use a measuring cup (or measuring spoons) to measure the amount of moisture accumulated. Record findings on your data sheet.
7. Repeat step five 48 hours (two days) after the start of the experiment.
8. Repeat step five 72 hours (three days) after the start of the experiment.
9. Repeat step five 96 hours (four days) after the start of the experiment.
10. Repeat step five 120 hours (five days) after the start of the experiment.
11. Record your results and conclusions on the Experiment Log

Discussion Questions

1. What differences did you observe between the leaves in bags exposed to air versus those that were prevented from receiving air due to the petroleum jelly covering?