Take a potted plant.
Cover it by polythene so that its roots along with soil get completely covered. This will prevent evaporation of water from the soil.
Put a bell jar over the potted plant.
Apply vaseline on the rim of the jar, this will prevent air from entering the jar from outside.
Keep this set-up in the sunlight for some time.
You will find drops of water on the inner side of the bell jar. These drops are due to the process of transpiration.
