B6: Measuring water uptake and water lossPractical B6: Washing line method
How to use a potometer (bubble and weight potometer) to investigate the factors affecting the rate of water uptake by a plant and washing line method to investigate the factors affecting the rate of water loss from leaves.
Use the washing line method to investigate the factors affecting the rate of water loss from leaves.
Procedure
Remove a number of leaves from a plant.
Smear petroleum jelly over the cut stalks to make them waterproof.
Measure the mass of each leaf.
Using paperclips hang the leaves on a line of string (held up by 2 retort stands).
If investigating the effect of temperature on water loss by a leaf, hang half of the leaves at a high temperature and the other half at a low temperature.
After a period of time, find the new mass of each leaf.
Calculate the average loss of mass at each temperature.
