A potometer, also known as a transpirometer, is a device used to measure the rate of transpiration, or the rate of
water loss from a plant's leaves. Potometer readings are typically affected by environmental factors such as
temperature, light, humidity, breeziness, and the plant's available water supply. Inserting a leaf-bearing plant
stem snugly into a piece of plastic tubing and connecting the tubing to a pipette, or graduated length of glass
tubing, full of water, yields a very simple potometer. Potometers are frequently assembled underwater, with
everything submerged except the leaves, to prevent any air from entering the apparatus. The level of water in the
pipette changes over time.