Progress in science always depends on well-planned experiments that yield communicable results. The scientific method involves tasks like asking a question, researching it, making a hypothesis and then testing the hypothesis. Let us discuss the controlled variable in detail.
The experiment should be a fair test in which we change only one variable. A variable may be a factor, trait or condition. Understanding the three basic kinds of experimental variables which are dependent, independent and controlled variables will help make the experiment a success.
The variable that the scientist changes during their experiment are the independent variable. For example, take the experiment as a “cause and effect” exercise.
Here the independent variable is the “cause” factor. An independent variable is a variable that we can change or control in a scientific experiment. It will represent the cause or reason for an outcome.
Therefore, independent variables are the variables which the experimenter changes to test their dependent variable. A change in the independent variable will directly cause a change in the dependent variable. However, we can measure and record the effect of the dependent variable.
Independent Variable Examples
Suppose a scientist is conducting an experiment for the effect of light and dark on the behaviour of moths. He is doing this by continuously turning a light on and off. Thus here the independent variable is the amount of light and the moth’s reaction is the dependent variable.
This is the study to determine the effect of temperature on plant pigmentation. Here the independent variable (cause) is the temperature, while the amount of pigment or colour is the dependent variable (the effect).
A dependent variable is the one which we can test in a scientific experiment, in order to get its values. The dependent variable is obviously ‘dependent’ on the independent variable.
Hence as the experimenter changes the independent variable, we can now observe and record the change in the dependent variable. So while taking data in an experiment, the dependent variable is the one being measured.
Dependent Variable Examples
A scientist is testing the effect of light and dark on the behaviour of the moths by turning a light on and off. Here the independent variable is the amount of light and the moth’s reaction is the dependent variable.
A change in the independent variable i.e. amount of light directly causes a change in the dependent variable i.e. moth behaviour.