Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers.
Here are some fun experiments you can try in the classroom to explain transpiration to your students.
Plant in a bag
Materials Required: Plastic Bag, String and a Plant
Pick a plant and place a plastic bag on a small branch with leaves. Leave it for two to three days. Make sure that it is properly tied.
Water the plant normally every day and observe the plant for a few days. You will notice the plastic bag getting misty and water accumulation inside the bag.
This is the excess water that is transpired through the leaves.
Four Leaf Experiment
Materials Required: Vaseline, String and Four leaves
Take four banyan leaves and name them A, B, C and D. Apply Vaseline to both the surfaces of A, lower surface of B with stomata, upper surface of B without stomata. Don’t apply Vaseline on D.
Tie the leaves with a string and leave it for a few days. Ask your students to observe the leaves after a day or two and note their observations.
It will be seen that the leaf A that has been coated with Vaseline will look fresh and green as no transpiration occurs. On leaf B, transpiration would have taken place only on the upper surface and hence remains green like leaf A.
Leaf C would have shriveled to an extent as transpiration takes place only on the lower surface. Leaf D would have wilted completely.
Stomata help in gaseous exchange and water evaporation or loss from leaf surface. Hence, covering the leaves with Vaseline will close the stomatal opening present on leaf epidermis. This experiment thus proves that the rate of stomatal transpiration is higher than cuticular transpiration.
Are there any fun experiments that you have carried out in your class to explain transpiration to your students? Let us know of them in the comments below