Monday, January 18, 2010

What is the difference between the variable and the control in an experiment?

What is the difference between the variable and the control in an experiment?What is the difference between the variable and the control in an experiment?
Ugh. Lots of people get these confused. and confuse them with a constant.


A variable is something that changes during the experiment.


Variables come in two forms-- independent are the ones the researcher controls and dependent are the one that the researcher doesn't control directly, but measures to look for results.


A constant is anything in the experiment that doesn't change during the whole experiment.


The control is used for comparison and the researcher knows what to expect from the control.


So a researcher looking for the effect of a new fertilizer on plants would vary the kind or type of fertilizer (variable) and measure the plants height (variable). They would keep the amount of sun and water the same (constant). They would grow at the same time a plant given no fertilizer (negative constant) and a known effective fertilizer (positive control).What is the difference between the variable and the control in an experiment?
well, the control is the unchanged and untampered with part of the experiment. the variable is what is changed and what is documented when compared to the control. so control stays the same and the variable changes.
The control is the substance without any additive.





Example to test the effect of salt on water.


The control is water the variables maybe a 10% solution of salt a 20% solution of salt and a 30% solution of salt.





All four must be kept in the same environment from the beginning of the experiment until the end. If there is any change the control must also be tested to insure the environment did not have an effect.





The sun, extreme heat, extreme cool, extreme moisture, extreme dryness etc could all effect the experiment but they should also effect the control if done properly.
A variable is the thing that you're testing for in the experiment. A control is the thing without the thing you're testing for. For example, if you wanted to see if corn grew better if you added aspirin to its water, your variable would be corn grown with aspirin added, say some corn with one tablet a day, another with two tablets a day. The control would be corn grown with just plain water with no aspirin added.
you know the results of the control.
The control is something that always stays the same no matter what while the variable is what is changed. Like say you have a pack of gum...... you leave it at room temperature for five days and that would be the control. Then the temperature could change between really hot and freezing to see how the gum changes. So the temperature is your variable. Hope that helps....... and i really hope i didn't confuse you
The control is not experimented with or changed in any way. The variable is where you conduct the experiment, you then compare the variable to the control to see how the experiment changed it... Hope this helps..
in an experiment, the control is what is kept constant, with no change at all, the variable is what will be changed to see what the effect will be
The variable is the group that say, for instance, actually gets the drug.





The control doesn't.
i thinkt that the control stays the same and the variable gets changed throughout the different stages of the experiment. i.e. testing solubility-the amount of liquid stays the same (control) but the amound of solid doesn't (variable).

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