Controlled Experiment Definition

Are you looking for a controlled experiment definition? Experimental testing is required by the scientific method to test the validity of a theory believed to answer a scientific question. During scientific testing, a scientist typically designs a controlled experiment to test a theory. Controlled experiments compare an experimental or test group to a controlled group of test subjects, limiting the factors affecting test results. What should you know about a controlled experiment?

What is the basic definition of a controlled experiment? A controlled experiment is a scientific experiment during which a control group and an experimental group are subjected to an identical set of variables or factors—except for the variable being tested by the study. Only the experimental group is exposed to the tested variable so that the variable’s effect on the tested group may be determined—without the impact of outside factors.

What is an example of a controlled experiment? One of the earliest controlled experiments was conducted by 17th century Italian scientist, Francesco Redi. Redi sought to disprove the belief that maggots spontaneously generated from non-living objects. He conducted a controlled experiment in which he placed a piece of meat in each of eight jars. He created a control group by covering four jars with muslin cloth. The experimental group of four jars was left uncovered to test the theory that exposure to the open air environment—not spontaneous generation—led to the formation of maggots on the meat. As Redi theorized, maggots formed only in the uncovered jars—not within the controlled set—indicating that spontaneous generation was not responsible for maggot growth.

What are the requirements for a successful controlled experiment? Controlled experiments must have both an experimental test group and a control group. Both groups must be tested under identical circumstances—with only the experimental group subjected to the variable under study. In order to be considered a valid scientific study, a controlled experiment must be reproducible under the same circumstances and variables.

What are the pros and con of a controlled experiment? Controlled experiments lend greater validity to the reported cause and effect relationship of a tested variable on the experimental group as outside factors are limited. Controlled experiments are easier to replicate under the original test conditions. Unfortunately, every scientific test cannot be controlled in a rigid laboratory setting. Critics of controlled experiments are quick to note that controlled laboratory experiments often create unrealistic real-world generalizations where additional factors beyond the test variables can and often do contribute to results.

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