Editing Potometer (section)

==Preparation==
* Cut a ''leafy'' shoot for a plant and plunge its base into water. This prevents the xylem from taking up any air. Wetting the leaves themselves will alter the rate of transpiration.
* Immerse the whole of the potometer into the sink. Move it about until all the air bubbles come out.
* Recut the shoot's stem underwater.  Put it into the bung; grease the bung with plenty of petroleum jelly  if it doesn't stay and then put the bung into the potometer.
* Make sure the tap is closed, then lift the whole assembly out of the water.
* Leave the end of the capillary tube out of the water until an air bubble forms, then put the end into a beaker of water.