Question

The figure given below represents an experimental setup with a weighing machine to demonstrate a particular process in plants.

The experimental setup was placed in bright sunlight. Study the diagram and answer the following questions.

1. Name the process intended for study.
2. Define the above-mentioned process.
3. When the weight of the test tube (A and B) is taken before and after the experiment, what is observed? Give reasons to justify your observation in A and B.
4. What is the purpose of keeping the test-tube B in the experimental setup?

Answer 1

1. Process intended for study in the given experiment:

• The given experiment was done to study the transpiration process.

2. Definition of the process:

• Transpiration can be defined as a process of water loss from the leaves of a plant through its stomata.

3. Observations and their justifications:

• Observations:

1. It was observed that the weight of test tube A decreased after the experiment.
2. Another observation was that the weight of test tube B remained unchanged.

• Justifications:

1. There was a decrease in the weight of test tube A because the water was lost through stomata due to the transpiration process.
2. As there was no plant in test tube B, no transpiration occurred. Thus, no water loss occurred. So, the weight of the test tube did not change.

4. Purpose of test-tube B in the experimental setup:

• Test tube B was used as a control experiment for the comparison of water levels with another test tube where transpiration occurred.