Question

The set up shown alongside was kept in sunlight for an hour. It was observed that drops of water appeared on the inside of the polyethylene bag.

1. Name the process which is being demonstrated.
2. Why was the pot and its soil left uncovered by the polythene bag?
3. Why was the pot left in the sunlight?
4. Suppose the pot in this experiment was placed inside a dark room instead of placing it in sunlight for some time. What difference will be noticed?

Answer 1

1. The process demonstrates the loss of water that has appeared in the polythene bag is transpiration.
   As the potted plant covered with polythene bag is kept in the sunlight there will be loss of water through the stomata present on the leaves. The water drops will appear inside the polythene bag as a result of loss of water from the stomata. This is due to transpiration
2. As the potted plant is kept in the sun. The water vapours will also be given by the pot and the wet soil. These vapours (water drops) will also go inside the polythene if it covers the pot and the soil.
   We left the pot and soil uncovered by the polythene so that we may find the loss of water from the aerial parts of the plant covered with a polythene bag. This shows that the water gets deposited in the polythene bag has come from the aerial parts of the plant.
3. As we keep the pot in the sunlight the stomata will open and the loss of water i.e., transpiration takes place from the aerial parts of the potted plant and the stomata. The loss of water will be more (transpiration) in the sun, and water vapours will appear in the polythene bag very soon.
4. As we keep the pot inside the room, the stomata will not open fully and the rate of loss of water will be very-very less, and no water vapours will appear in the polythene bag. By keeping the pot in the room the loss of water will be very less and as a result, the transpiration will be very less.