Scientific variables are variables that are associated with the scientific method. The scientific method is a process that scientists use to explore the relationships between variables (Helmenstine, 2013). The process includes a series of steps you would follow to determine if any relationship exited between the variables you want to study. The steps in the scientific method are: 1) Identify the problem; 2) observe and gather data; 3) formulate a hypothesis; 4) analyze the data that was collected; 5) interpret the results; and, 6) form conclusions (Lee, 2014). The variables studied in this process are scientific variables.
Scientific variables fall into one of three categories. The first category is what is known as controlled variables. A controlled variable is held constant during the course of the experiment so that it will not interfere with the results. They are kept from changing so that they will not influence the outcome of the investigation.
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A second category of scientific variables is known as independent variables. An independent variable is one that the experimenter manipulates during the investigation to see what affect the changes have on the variable being investigated (Saunders, Lewis and Thornhill, 2009). The experimenter has hypothesized that changing the independent variable will cause a change in the variable under study, so it is important that the independent variable be changed.
The third, and final, category of scientific variables is known as the dependent variable. This is the variable being studied by the experimenter. It is the variable that is expected to change as a result of the changes in the independent variable (Saunders, Lewis and Thornhill, 2009). If this variable does not respond to changes in the independent variables, then the experimenter will probably reformulate the hypothesis and begin the experiment again.
As an example of scientific variables and how they are used, let’s assume that we are interested in knowing whether or not violent crime (i.e., armed robbery, murder, assault with a deadly weapon, rape, etc.) increases as the distance from the police district station house increases. We might formulate a hypothesis that says: The farther away a neighborhood, within the local police district, is from the station house, the higher will be the number of violent crimes against its citizens.
In this example, the hypothesis sets up the independent variable to be distance from the station house. In other words, as the distance from the station house increases, we would expect the number of violent crimes to increase. As the independent variable changes, we would expect to see a change in the dependent variable. At one mile from the station house, the level of violent crimes committed would be lower that they would be at two miles from the station house.
The dependent variable in this hypothesis is violent crime. Our expectations are that the number of violent crimes will go up as we move farther away from the station house. In this example, we are looking for a change in the number of violent crimes as we move our location away from the station house. If it turns out that the number of violent crimes does not increase, then we can say that there is a limited or no relationship between the distance a neighborhood is from the station house and the number of violent crimes committed in that neighborhood.
There are, of course, other variables that could affect the number of violent crimes in a given neighborhood. However, we are not interested in those variables in this experiment and hypothesis. They become control variables and are held constant as much as possible. Full control is never really possible, but the idea is to minimize their influence as much as possible.
- Helmenstine, A. M. (2013). “What is a Scientific Variable?” About Education. Available at: http://chemistry.about.com
- Lee, K. (2014). “How to Use the Scientific Method to Research Crime.” Ehow.com. Available at: http://www.ehow.com
- Saunders, M., Lewis, P. and Thornhill, A. (2009). Research methods for business students, 5th ed. Harlow, England: Pearson Education.
