Investigation: what conditions affect water loss from leaves?

Essay by vikki_xxxHigh School, 10th gradeA+, November 2002

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Biology Investigation.

What conditions affect water loss from leaves?

Vikki Merriman 9Y


I predict that the higher the temperature, the more water the leaf will lose. In hotter atmospheres, more water will be evaporated off the leaf. So, if we put a leaf in an oven, more water will be lost than a leaf we put in a fridge.

Scientific Background.

Transpiration is the loss of water from the plant. Stomata close when there is little water coming up through the roots so that no water is lost through the leaves. This means that no Carbon Dioxide is getting in which therefore stops photosynthesis. The rate of transpiration is affected by the amount of light, the amount of air movement, the temperature and the humidity of the surrounding area. (More water is lost in hot, dry, windy, sunny conditions.)

These two pictures show cross-sections of leaves and the most important parts are labelled.


15 petri dishes.15 leavesChemical balances


ThermometerTin Foil


I chose 15 leaves and measured their surface area and mass. We then numbered the leaves and put them in numbered petri dishes with the underside facing up. We then wrapped the petri dishes in tin foil so that the amount of light they got was constant otherwise this would have made it an unfair test.

We then put the petri dishes containing the leaves in their designated places (three in each of the following - freezer, fridge, cupboard, window sill and oven). We also put a thermometer in with the petri dishes. Leaves 1, 2 and 3 went in the freezer. 4, 5 and 6 were in the fridge. 7, 8 and 9 went on the window sill. 10, 11 and 12 went in a cupboard and 13, 14 and 15 were placed...