Science Fair Insider: The Independent Variable Explained

Ok, so it’s science fair time.

Don’t panic.

It can seem crazy what kids are learning in school these days. Unfortunately, as a parent, you’re also expected to keep up with them.

This means getting regular refresher courses on math, literature, and the scientific method.

That last one especially can get pretty tricky.

You may have read (perhaps on the assignment sheet your baby brought home) that you and your kid need to be the co-creators of an awesome experiment.

Putting together an experiment can be difficult, especially if you yourself need to brush up on your science skills. It gets even more dicey when it comes to independent variables within the experiment.

Read on to delve into the exciting world of variables, discovering how to define and use them to your advantage in your experiment of choice.

Defining and Classifying an Independent Variable

A variable in a scientific context means any factor which can be controlled, measured, or changed within an experiment to affect the results.

An experiment executed according to the scientific method has three variables: dependent, independent, and the control variables.

Independent Variable

What is an independent variable?

According to the University of North Carolina, it’s the variable that you manipulate. Many people refer to the independent variable as the “controlled variable”, since it is the variable you have control over. Remember, this is not the same as the “control variable” described below.

The independent variable definition can be tricky, but it’s much easier once you understand its purpose within an experiment.

For example, say you and your little science prince or princess are doing an experiment on how different types of music affect plant growth. In your experiment, the music is the factor you control or manipulate. That makes it the independent variable.

Dependent Variable

The dependent variable is the factor that you measure. It’s easy to remember, if you think of the outcome of this variable as being “dependent” on the control variable.

If you performed the experiment mentioned above, the dependent variable would be the growth of the plants. You can think of the independent and dependent variables as having a cause-and-effect relationship.

The way you manipulate the independent variable causes the outcome or set of outcomes for the dependent variable.

Control Variable

Control variables are those factors in the experiment that you need to keep the same no matter what. Having control variables ensures that the results of your experiment change only in response to the independent variable.

In the hypothetical music and plants experiment, you would have several control variables. These would include the type of plant used in each test and the time of day you played music to the plant, among other things.

The Impact of an Independent Variable on the Scientific Method

The independent variable is one of the most important parts of the experimentation process.

It is the independent variable which determines the outcome of the entire experiment. By using one independent variable over another, you can study the effect of different stimuli on your dependent variable.

The independent variable should be changed each time a separate stage of your experiment is carried out. Many experiments need quite a few stages before conclusions can be drawn.

For example, you won’t draw any conclusions from simply observing a plant which you played heavy metal to for a week. You at least have to test out one or two other kinds of music to see how the plants behave in another environment.

It’s very important to remember that, although you may experiment with more than one independent  variable, you should never change the control variables.

Remember, the control variables are kept the same in order to protect your dependent variable from being affected by something other than your independent variable.

Tweaking the Independent Variable to Get More Results

In order to learn more about the cause-and-effect relationship between two variables, it is often necessary to test with more than one independent variable.

This is especially true with experiments like the effect of music on plant growth. With this experiment, it’s impossible to tell if the effects are from the music if you only test one type of music.

The “effects” you think you are witnessing may be caused by outside factors. Say you played hardcore metal to a basil plant, and a week later it was wilted. You don’t actually know that the hardcore metal music caused the plant to wilt.

However, by testing the effects of Beethoven out on the same type of plant and observing the results, you may detect a difference and be able to draw some conclusions.

It’s necessary that you perform a separate test for each independent variable you wish to try. If you played Beethoven and metal music to the same plant, how would you be able to tell which music has which effect?

You’d just wind up with a very confused plant.

Learn About the Independent Variable to Keep Your Child’s Science Fair Project on Point

The most important thing you can possibly do when science fair time rolls around is keep a good attitude and a clear head. Remember, science is a fun learning opportunity for all. So, get ready to dive into the exciting world of variables.

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