If you’re looking for an identifying independent and dependent variables in science worksheet with an answer key, then look no further!
What is a variable?
A variable is anything that is changing. Variables are all around us: the weather, your mood, what you had for breakfast, your age, and more! Variables are interesting to scientists because as they change, they affect other things.
Scientists are curious about the ways variables affect each other. Below is a list of some questions scientists might ask about how variables interact.
- How do carbon dioxide levels affect the global temperature?
- How do vaccines affect the rates of autism?
- How does sugar affect heart health
- How does standardized testing affect teaching and learning methods?
What are independent and dependent variables?
Identifying independent and dependent variables is one of the most important steps in any scientific investigation. First, the independent variable is the variable that is changed by the investigator or scientist. It is sometimes called the manipulated variable for this same reason.
Next, the dependent variable is the variable that is measured. It is the variable that depends on the independent variable. The dependent variable responds or reacts to changes in the independent variable. For that reason, the dependent variable is sometimes called the responding variable.
Identifying independent and dependent variables in science worksheet
Why are independent and dependent variables important?
Let’s look at an example. A theater is wondering how the price of tickets affects concert attendance. They decide to do an investigation. In January, the theater hosts a Justin Bieber concert. They price the tickets at $50 each. On the day of the concert, they record that 1500 people came to the concert. In February, a traveling pair of banjo players asks if they can hold a concert at the theater. The theater agrees and decides to complete their investigation by pricing tickets to The Banjo Brothers at $10. On the day of the concert, only 100 people come. The workers conclude that, based on their investigation, more expensive tickets result in greater concert attendance.
Is this a fair investigation?
The answer is no! In this investigation, the independent variable (ticket price) and the dependent variable (concert attendance) were clearly defined. Sadly, everything went downhill from there because the investigators forgot to control other variables.
Controls or constants are the other variables which might affect your investigation’s results. You need to keep these the same throughout your study if you want valid results. Some variables that may have affected this group’s investigation include:
- Public interest – do more people like Justin Bieber than The Banjo Brothers? Can you really compare ticket sales to their two concerts?
- Other events – Is it possible that people really love The Banjo Brothers but that there was a big sporting event in the city on the same night that people wanted to attend even more?
The only way to truly determine how ticket price affects concert attendance would be to have two identical concerts in the same town on the same night with the same performer singing the same set of songs and to offer those tickets to the same people at two different prices. Then you could record the number of people in attendance at each concert to determine how price affects attendance.
Notice that only the independent variable, the manipulated variable, changes here? And the dependent variable responds. This is the definition of a controlled experiment. Of course, this is usually impossible. That doesn’t stop scientists from trying, though! We do our best to eliminate other factors which might influence our results by keeping them the same. Doing so allows us to complete a controlled experiment and to achieve reliable results.
Graphing independent and dependent variables
If you’re ever looking at scientific data, most likely the data that will be reported is information on the independent and dependent variables. In almost every case, the independent variable is graphed on the x axis (the bottom line) and the dependent variable is graphed on the y axis (the up and down line). Information about the controlled variables is rarely included because, quite frankly, it should be irrelevant. Seeing a simple graph of the independent variable and dependent variable together helps scientists to determine the relationship of the two variables.
In this case, if the experiment was done carefully and correctly, the scientists would conclude that as ticket price increases, concert attendance decreases.
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