In scientific terminology, was is a control, and what is a variable???

I need help with my science fair project, have any websites I could refer to??In scientific terminology, was is a control, and what is a variable???
Thats pretty basic. The control in the experiment is the constant. Something that has a predictable outcome. The variable is the item that you are experimenting on.


Kind of like haveing a placebo in a drug test...In scientific terminology, was is a control, and what is a variable???
When you want to see if something changes something else, you have to make sure that you are only testing ONE thing.





For example, if you wanted to know the effects of sunlight on plants, you would just need to put one plant in the dark and one in the light and see what happens, right?





Wrong. You have to make sure that the amount of sunlight is the ONLY thing you are testing. So you have to make sure that the plants are of the same species, age, get the same amout of water, have the same soil.... etc.





So, one plant will be the CONTROL plant. This is the one you leave out in normal conditions. The other plant is the one you will apply the VARIABLE to: no sunlight.





All other things (water, amount of soil in the pot) being the same, any difference in the two plants will be due to the variable: no sunlight.
Like everyone else has said, a control is something that stays the same and a variable is what changes. Say you are doing an experiment about water temperature. The control would be a 50 mL of water at room temperature. The variables could be a 50 mL glass of water at 100 degrees and a 50 mL glass of water at 32 degrees. You would than compare that variables to the control to gather results. In this case the 50 mL of water at 100 degrees would be boiling and the glass of 32 degree water would be frozen.
Hey there: Best of luck with your project.





Check out this web site for some basic info on the scientific method: http://school.discovery.com/sciencefairc鈥?/a>





In a nutshell, if you have an experiment and plan to do something to see what happens, the control is a group that you don't do anything to.





For example, if your experiment is to see if feeding cats tuna in addition to their normal cat food makes them sleep more, the control group is the cats that just get the regular cat food. The cats that also got the tuna are the experimental group.





A variable is something that varies. (Sorry - I couldn't resist. I'll try harder now!) For example, lets go back to the cats and tuna experiment. You could vary the amount of tuna fish the cats in the experimental group eat every day. Then, the amount of fish would be a variable. Or, you could feed some cats in the experimental group tuna, and feed other ones catfish (sorry, I think that was the last bad joke, but I can never be sure...) Then, the type of fish would be a variable.





If some of this makes no sense, add a note, and I'll try to explain better. Best of luck, and try to find a project you'll enjoy.
Lets say that you are trying to demonstrate that cofee makes you alert and nervous: So you make tow groups:


group 1: 5 people that will not drink cofee (control group)


group 2: 5 people that WILL drink 15 cups of espresso (variable group)


then, you will perform a test or a questionnaire to evaluate the degree of alertness and nervousness. Obviously you will notice that the varaiable group is more alert and nervous.
Control - stays the same


Variable -changes





http://www.fcps.k12.va.us/McNairES/expde鈥?/a>
In an experiment, a variable is the element that is manipulated or altered by an individual, whereas the control is the element that prevent extraneous factors from hindering the results of the experiment (it stays the same, as opposed to the variable which changes).
control is the things that you keep the same throughout the whole experiment like time





this may help





Dependent variable


Response in the experiment


Y-axis





Manipulative in the experiment


Independent variable


X-axis