One is called the dependent variable and the other the independent variable. The independent variable is the variable the experimenter manipulates or changes, and is assumed to have a direct effect on the dependent variable. For example, allocating participants to either drug or placebo conditions independent variable in order to measure any changes in the intensity of their anxiety dependent variable.
In a well-designed experimental study , the independent variable is the only important difference between the experimental e. The dependent variable is the variable being tested and measured in an experiment, and is 'dependent' on the independent variable.
An example of a dependent variable is depression symptoms, which depends on the independent variable type of therapy. Possible dependent variables include: number of beans, weight of the plant, leaf surface area, time to maturation, height of stem. Independent -- is what is varied during the experiment; it is what the investigator thinks will affect the dependent variable.
Student performing science experiment with variables. Different Types of Variables in Science As a budding scientist, you want to learn about the world around you. Independent Variable In an experiment, you need some type of control.
Examples of independent variables include: In an experiment to see what brand of diapers hold the most liquid, the independent variable is the brand. In an experiment studying plant growth in different types of soil, the independent variable is the soil. Dependent Variables The dependent variable is your effect. For example: In the diaper experiment, the dependent variable might be how much liquid you add to the diapers to see their liquid capacity.
In the plant experiment, the dependent variable would be the growth of the plant. It is going to change depending on how you change the independent variable soil or amount of light.
Control Variables When doing a science experiment, some variables need to remain constant. The control variable in the diaper experiment could be the size of the diaper you use. Varying the size of the diaper could skew your results. So, you should keep all the other variables the same you control them so that you can see only the effect of the one variable the independent variable that you are trying to test. Similar to our example, most experiments have more than one controlled variable. Some people refer to controlled variables as "constant variables.
In the best experiments, the scientist must be able to measure the values for each variable. Weight or mass is an example of a variable that is very easy to measure. However, imagine trying to do an experiment where one of the variables is love. There is no such thing as a "love-meter.
So, love is not measurable in a scientific sense; therefore, it would be a poor variable to use in an experiment. In some experiments, time is what causes the dependent variable to change. The scientist simply starts the process, then observes and records data at regular intervals. When a scientist performs a test or survey on different groups of people or things, those groups define the independent variable. For example:. For example, something might be either present or not present during an experiment.
Here is a sample containing the variables and hypothesis. Menu Science Projects. Project Guides. View Site Map. Science Projects. Grade Levels.
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