Using a potometer

- Construct potometer underwater, so no air enters - Cut shoot at slant, increases SA for uptake - Insert shoot underwater - Remove apparatus from water - Dry the leaves, allows time to acclimatise - Remove end of capillary tube until 1 air bubble has formed - Put end of tube back into water - Record the starting position of the air bubble - Start timer, record distance moved by air bubble per unit time e.g. per hour - Rate of air movement = estimate of transpiration rate - Change 1 variable, everything else kept constant