What is my control variable?

My Science Experiment





My problem: What helps plants grow better? Light or darkness.





I am conducting a science experiment testing the factor of darkness VS sunlight on two pansies potted with the same type of soil, in small, identical clay pots. My hypothesis for the test is that the pansy subjected to light will live longer than the pansy subjected to dark.





My list of constants:


鈥?The pansies, because they are the same type of flower.





鈥?The pots, because they are both small, identical, clay pots.





鈥?The soil in the pots, because they are the same type of soil.





My control variable is the ............................(


My dependant variable is the how much the pansies grow. The independent variable is theamount of light given to the pansies.





My plan for the experiment:


I will take two pansies potted with the same type of soil, in small, identical clay pots, and subject Pansy #1 to sunlight, and Pansy #2 to darkness. After|||actually, a more appropriate set up would involve at least three pansy plants (significant sampling sizes may be beyond the scope of this particular experiment): one grows in continous dark, one grows in continuous light, one grows outside with a "normal" light/dark (day/night) cycle--your control plant (but actually, it would be better if you had this plant exposed to light that is timed for 12/12hrs light/dark...because being outside would make this plant different from your test plants)





you would measure the difference in growth of the plants grown in the dark/light in comparison to the control plant's "normal" growth.





other constants you might want to consider: temperature, humidity, amount of water, amount of soil, time of water, time when you take measurements.





and your variable would be different light exposure (constant dark/constant light). you could also get a little more fancy by seeing amount of light provides optimum growth where you would have different pansies growing exposed to 24hrs, 18hrs, 12hrs, 6hrs, 3hrs, 0hrs of light.|||Your control variables are the constants that you listed; pansies, pots, and soil. Control variables are just the things kept the same throughout the experiment.





I'm doing an experiment similar to this too ;)|||The control varible, or rather, the independant varible, or even the manipulated varible, depended where you went to school, or where you work, would probably be the light/dark factor, because you can put the plant in the light, but at the same time, you can put it away in the dark. It can't be the actual flowers, because you can't control how fast/high they grow. You can to a point, but not completely.|||The amount of light.