What Are Independent Variables?

In any research that you undertake, there are two major types of variables: Independent and dependent.

When testing a hypothesis, you need to change one of the conditions, keeping other conditions constant so that you can study the effect of this change on your research. The change that is brought about as a result of your manipulating the variable is known as the dependent variable and the factor that you have changed is the independent variable.

For example, you are studying the effect of temperature on carbon dioxide solubility in water. To study this, you will progressively increase the temperature and document your result at each step. Here, temperature is the independent variable (the one you are consciously manipulating) and solubility is a dependent variable (which changes as a result of the change in the independent variable).

You could say thus that the independent variable is the cause and the dependent variable is the effect of any action or observation.

Just a little know-check:

If you have to study the effect of light on a growing plant, what would be the independent and the dependent variables?



Don't peak!!



(Answer: Amount of light you provide to different test plants is the independent variable and the amount of growth occurring in each case is the dependent variable.)

In science experiments, independent variables are the variables you can change and are not influenced by any other factor. On the other hand, dependent variables are affected by the independent variables and are the variables you want to test. Basically, the independent variable is your "input"; the dependent variable, "output".

It would make more sense if I show you two examples:

1. You want to know what type of ball will bounce the highest. Your possible independent variables are material of ball and height from which ball is dropped. The dependent variable is bounce height.


2. You want to know if emotional stress affects reaction time. Independent variable: stress/no stress. Dependent variable: reaction time.