Observe the picture of an activity given as fig. 7.4 carried out with leaves of plants and polythene bag. Now answer the following : (a) Which process is demonstrated in the activity? (b) When will this activity show better result – on a bright sunny day or a cloudy day? (c) What will you observed in the polythene bag after a few hours of setting up the activity? (d) Mention any one precaution you must take while performing this activity.

Question

Philoid · Accepted Answer

(a) The leaves of plants give out water constantly in the form of water vapour (which goes into air). So the process demonstrated in the activity is transpiration.

(b) This activity will show better result on sunny day because rate of transpiration is maximum in the presence of sunlight.

(c) After a few hours of the setting of the activity, we can see a number of water droplets on the inner side of polythene bag because the leaves are enclosed in the polythene bag, the water vapour cannot escape into air. So the water vapour given out by the covered leaves keeps on colleting inside the polythene bag. Some of these water vapour condenses to form tiny drops of water.

(d) While performing this activity we need to take some precautions. The polythene bag used should be clean and dry and it should be sealed properly so that no air passes inside it.