What is a constant setup experimental setup control setup and an experimental variable?

Control Setup

The constant control set up is where you have every thing "normal" to use to compare your experimental set up with the variable to. This has no variables and is always constant.

For example if you wanted to see if plants would grow faster watered with sugar water or plain tap water, your constant control set up would be the plant watered with plain water. Since this is the "normal" condition with no changes it is the control setup.

Additionally there are two kinds of controls, positive and negative. Positive controls will have an indication or contain the specific substance that the test or instrument is used for. On the other hand, negative controls don't contain that specific substance or instrument. For example if you were testing the effects of aspirin on inflammation and you gave a group, 20 mgs of a placebo, that would be a negative control. Opposite to that would be a positive control, if you were testing the same thing and instead gave the group 20 mgs of the aspirin.

 

Experimental Setup

In short the part of the experiment that contains the variable is called the experimental setup. This is identical to the control setup except in one way. One change is made to the set up, this change is called the variable.

In the example of the plants watered with tap or sugar water, the experimental set up would be the plant watered in the sugar water. Since this is the setup an which you are testing this, it is called the experimental (think of the experimental setup as a test) setup.
 

Experimental variable

The experimental variable is basically what you are changing between the control and experimental setups.

In the example, your experimental variable would be what the plant is watered with. So in this case, it would be the sugar water.