TRANSPIRATION (DESIGN EXPERIMENT)
Water is essential for the survival of all living things. Green plants depend on water not only for photosynthesis, but also as the basis for all chemical reactions. Water is taken in by the roots and passes through the plant into the leaves. Excess water is released into the air as water vapour. This process is known as transpiration.
Is the rate at which water lost influenced by the structure of the leaves and the environmental conditions?
If the structure of the leaves and the environmental conditions change, then the rate at which the water is lost from the plant will also be influenced.
Dependant variables: temperature and time of the day.
Independent variables: the rate of transpiration.
o Top loading balance
o Two leafy shoots from an actively growing plant.
o Two measuring cylinders.
o Paraffin oil
o On the first day, carefully cut two leafy shoots from a plant and take them into the laboratory.
o Stand one shoot in a measuring cylinder and fill it with water to the top measuring mark.
o Carefully pour paraffin oil down the inside surface of the cylinder so that there is a thin layer of oil over the surface of water.
o The other shoot should also be set up in the same way but before placing it in the cylinder make sure that it should be treated in one of the four ways:
A- All the leaves are removed
B- Vaseline is smeared on the underside of each leaf
C- Vaseline is smeared on the upper surface of each leaf
D- Vaseline is smeared on both surfaces of the leaf
o Then weigh the entire set up (plant, cylinder, water and oil). Record the total mass in grams for each plant.
o Read the level of water in each measuring cylinder for each plant.
o Leave the plants for 24 hours.
o On the second day, record the new level of water in each measuring cylinder.
o Weigh the whole set up after 24 hours. Record the results....