How can i determine a controlled variable in an experiment?

To really know your experiment you must consider all the pertinent variables? What are you controlling? Is the sample in a water bath to control temp or in a temperature controlled oven. Is pressure fixed or can it vary? Is humidity controlled or not. Lots of things come into play during an experiment, as well as lots of things we don't anticipate, but by controlling critical variables we can examine trends caused by other factors.How can i determine a controlled variable in an experiment?
There are three types of variables in a controlled experiment.





The independent variable is the one that you change throughout the experiment to see how it affects the outcome.





The dependent variable is the one that you observe or measure to see what happened.





The controlled variables are all the other things that keep the same to make sure that your independent variable is the the only thing that is changing.





(You can also have a control group which is the group that exists in ';normal'; conditions and against which you compare your experimental groups.)





For example, I want to know if the color of light affects the color of blossoms on a plant. I grow one set of plants in ';normal'; daylight. The other groups I grow in light of varying wavelengths (different colors of light).





My independent variable is the wavelength/color of light.





My dependent variable is the color of the blossoms.





My controlled variables are all the things I want to hold steady across the experiment - things like the type of plant, the temperature, the soil composition, the amount and type of fertilizer, the amount and type of water, the type of container the plants are grown in, and so on.





The control group is the group of plants grown in ';normal'; daylight.How can i determine a controlled variable in an experiment?
A controlled variable in an experament is waht ever stays the same.
The controlled variables, also known as independent variables, are the ones that you manipulate or change in the experiment to determine how it is correlated to the dependent variables.