Transpiration Lab Bio 20(1) (1).docx - Transpiration Lab...

Plants play an important role in the biogeochemical cycling of water through the biosphere.
Plants take up water through their roots either from the lithosphere or the hydrosphere.
Plants also lose water to the atmosphere by the process of transpiration (evaporation from
plants). In this lab you will measure the rate at which transpiration occurs, and what factors
effect the rate of transpiration.
Transpiration Lab
Biology 20: Hydrologic
Cycle/Transpiration Lab
By: Siddhartha Paudel

Transpiration Lab
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PROBLEM:
How do different factors (wind, light, and heat) effect the rate at which transpiration within a plant
leaf occurs?
VARIABLES (for all manipulations):
Manipulated Variable: Factors affecting the rate of transpiration (wind, light, heat)
Responding Variable: The rate of transpiration (measured by change in mass (g))
Controlled Variable: Time period tested for (21 hours), type of plant leaf used, and the amount of
water in each beaker(10mL Cylinder)
Control Group: No manipulation group of plants (Not being affected by the different factors [wind,
light, heat])
HYPOTHESIS: (If… then… because…) (Light)
If we calculate the mass of the leaf before and after leaving it out for 24 hours with 10 milliliters of
water, then the leaf that is exposed to the light will have the highest rate of transpiration because
the stomata of the plant will be opened when it is subjected to a source of light. The stomata is a
pore found in the epidermis of a leaf, and it is responsible for regulating water movement through
transpiration. If the stomata is exposed to light, it will open, and will shift large amounts of water
out of the leaf through transpiration, which leads me to believe that the plant leaf exposed to the
source of light will have the most loss in water.