Question

Explain with an experiment the evaporation of water in vapour form during the process of transpiration.

Answer 1

Transpiration can be easily illustrated by positioning an adequately hydrated potted plant beneath a bell jar. The container and substrate are enveloped in plastic film or aluminium foil to prevent water loss, except through the plant. Moisture will soon accumulate on the interior surface of the bell jar. This humidity cannot dissipate into the external atmosphere from the soil or container because the bell jar is sealed with Vaseline and the pot is enveloped with polythene. The air within the bell jar becomes saturated with water vapour emitted by the plant, which then condenses and accumulates on the jar’s inner surface. A bell jar devoid of vegetation will not exhibit moisture droplets under the same circumstances.