And what is the differnce between a variable and a control?

Question

And what is the differnce between a variable and a control?

Answer 1

a variable is something that effects your final resualt, if your looking at weight loss for example; exercise, metabolism, diet, exercise are all variables that will effect the amount of weight a person looses. a control, or control group is something to look at for comparison, again with the weight loss example if you wanted to see how effective a specific type of diet is the control group will be people who aren't on the diet your looking at, but have similar metabolism, genetics, and exercise routines as the ones who are taking the diet, so you can say with more confidence that "it is only this diet that is causing the weight loss.

Answer 2

In an experiment. a variable is what you are changing as part of the experiment. A control is what you are keeping the same throughout the experiment.

For Example:

You want to know if hot or cold water freezes faster.

Your control would be amount of water and using the same freezer.

Your variables would be hot and cold water. Yeah I know this is a lame example:)  

Answer 3

In an experiment, you have some condition that you're testing. Say, whether fertilizer helps plants grow bigger.

However, you want to have something to compare to - unless you know how those specific plants grow without fertilizer, you won't know if the fertilizer made any difference.

Therefore, you have a few "control" pots and a few "experimental" pots. All the seeds are the same, and you grown them all in the same conditions, except for you add fertilizer to the experimental plants.

The "control" ones are what plants would grow like normally, and give you a means to gauge the effect of the fertilizer.

The "variable" in this experiment is fertilizer; it is the only difference between the different groups. If you wished, you could test a few different kinds of fertilizer against the same control plants - you'd just have several experimental groups.