What are three types of variables in science?
Independent and Dependent Variables
A dependent variable is a variable that changes in response to the changes in an independent variable. An independent variable is a variable that can be changed without affecting other variables. In an experiment, the independent variable is the factor that is changed or manipulated.
Independent and dependent variables
Independent Variable: A variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable.
Dependent Variable: A variable that is observed or measured in a scientific experiment. It is expected to change in response to the independent variable.
Control Group: A group in an experiment that does not receive the treatment or experimental conditions. The results from this group are then compared to the results of the experimental group.
Did you know?
The independent variable is the one that is intentionally manipulated in an experiment whereas the dependent variable is the one that changes in response to the manipulation of the independent variable. The independent variable is also known as the 'predictor' variable and the dependent variable is also known as the 'outcome' variable. The number of independent variables can determine how many dependent variables there are in an experiment. For example, if there are two independent variables, then there will be four dependent variables.
What is the difference between independent and dependent variables?
Think about an experiment you have conducted. What was the independent and dependent variable?
How do scientists use the scientific method to determine relationships between independent and dependent variables?
Clues
In pairs: Select one task
Question: In a scientific experiment, you are trying to figure out which factor affects the outcome. What are the independent and dependent variables?
Independent variables are factors that are changed or manipulated in an experiment. Dependent variables are factors that are observed to see how they are affected by the independent variables. Think about what you are trying to measure in the experiment.
A: Draw a picture of the experiment you are doing. Label the independent and dependent variables. B: Explain your experiment to your partner and see if they can identify the independent and dependent variables.
What is an independent variable?
- The variable that is measured or observed in response to the independent variable
- The variable that is manipulated or changed by the researcher
- A constant value in an experiment
What is a dependent variable?
- The variable that is measured or observed in response to the independent variable
- The variable that is manipulated or changed by the researcher
- A constant value in an experiment
In a study investigating the effect of temperature on plant growth, what would be the independent variable?
- Plant growth
- Time
- Temperature
In a study investigating how music affects concentration, what would be the dependent variable?
In a study examining the relationship between exercise and heart rate, what would be considered as an independent variable?
- Exercise
- Body weight
- Heart rate
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Work together in pairs: What is the difference between an independent variable and a dependent variable?