Hi! I am a high school student who is doing a
science project concerning the transpiration of plants. My question is
"Do plants transpire at the same rate under different sources of light?"
For my experiment I am planning to use 6 pansies and plant them in 6
2-liter bottles by cutting off 2/3 of the top. After planting them and
watering them I will reattach the tops to the bottoms and place one under
an incandescent lamp, one under fluorescent light, and the control under
natural sunlight (the three others I will use to repeat my steps for more
accurate results). After three hours I plan to remove the tops the
measure the amount of water.
Now, what I am wondering is do you have any suggestions on how I
could show my results? In the procedure, do you see anything I should change?
I also read that heat and humidity affects transpiration how would I
be able to tell how much the light alone affected the plants?
Something I would consider is that evaporation is not being controlled. You
might try setting up a simple transpirometer, placing the stem of your
sample plant into a tube with water that is otherwise sealed. Measure the
amount of water lost from the tube - it could only leave via transpiration.
You also need to control for surface area of the leaves - you might need to
find a way to convert the mass of the leaves to surface area, or trace each
leaf onto graph paper and measure the surface area by measuring the space on
the graph paper.
Good luck -
The following may be helpful.
Anthony R. Brach
When beta decay occurs, the electron produced has quite a lot of kinetic
energy. Enough, in fact, to exceed the attraction between the
newly-produced electron and proton, so the electron flies away.
Argonne National Lab
As with all science experiments, the key is to keep all the variables but
one the same, if heat, humidity, and all other conditions except the light
are the same, then results must be due to the different light.
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Update: June 2012