A control experiment is a type of scientific experiment that is carried out alongside the test experiment, with all variables held constant except for one variable which is under consideration. A good example of a control experiment is testing the importance of the light aspect in germination process, whose procedure is given below.
The germination process requires key aspectslike the presence of water, light, oxygen and growth hormones in order to be successful.
To conduct a controlled experiment, two experiments are required: an experimental group and a control group. One tin of seedlings should be exposed to light and other tin of seedlings exposed to darkness, ensuring all other factors are constant.
In the experimental group, dry agricultural soil should be filled into a tin and named tin A. Two to three bean seeds should be placed into the soil and water should be added. The tin should be placed by the laboratory window, and the process monitored while the observations are recorded.
In the control group, dry agricultural soil should be filled in a tin and named tin B. Again, two to three seeds should be placed into the soil, and adequate amount of water added in the soil. The tin should be placed in a well-ventilated yet dark room. The process should be monitored and the observations recorded.
The expected results are that the seeds in tin A, that were exposed to light germinate into healthy seedlings. The seeds in tin B that were kept in the dark room will have stunted growth and start to wither. This shows that light is an important aspect of germination.