Controlling for a variable is the act of deliberately varying the experimental conditions in order to take a single variable into account in the prediction of the outcome variable. Controlling tends to reduce the experimental error. A control is something that does not change in the experiment.
Two, the dependant and independent variable. The independent variable is what you are changing in each test and the dependant variable is what factor is being changed in it. There is also the baseline data which you are comparing everything to. For example if you are doing an experiment of whether the colour or water changes growth in plants (it doesn't) the different colours of water are the indepedent variable, the growth of the plant is the dependant variable and the baseline data would be a plant that is watered with ordinary water so you can compare to the other results and see if it makes a difference in a good or bad way.
A controlled experiment is one in which everything is held constant except for one variable. Usually a set of data is taken for a contol group , which is commonly the normal or usual state, and one or more other groups are examined, where all conditions are identical to the control group and each other except this one variable.
in a well tested experiment how many variables change
Only one. It is called a controlled experiment because your are only controlling one variable is being controlled, or changed.
One. You should only have two variables for the experiment and you manipulate the independent variable in a controlled experiment.
In the ideal case, one. But this is not always possible, making interpretation of the results more complicated.
Only 1
2
the only variables in an experiment are the independent variables [the thing in an experiment your going to change. and the dependent variables [the thing in an experiment your going to measure.
8
It depends what kind of experiment you do. For some you just need one. For others you may change two variables. In most cases you only change one
the dependant variable
Variables that do not change in an experiment are independent variables.
Variables that do not change in an experiment are independent variables.
2
2
the only variables in an experiment are the independent variables [the thing in an experiment your going to change. and the dependent variables [the thing in an experiment your going to measure.
8
It depends what kind of experiment you do. For some you just need one. For others you may change two variables. In most cases you only change one
the dependant variable
variables
the variables
variables
The thing that you change, from experiment to experiment.