For example, in biological experiments Pasteur, the variable is the presence or absence of bacteria into the two groups. Wherein a retort (retort prevents bacteria from entering) experimental group, normal bottle (bacteria can enter) is a control group.
experimental "and" control "is not clearly defined in biology, like mathematics," collection ", as just a basic concept. You can is understood as: experimental group refers to a portion of the experiment to explore the control group refers to a portion of the test compared typically, you can distinguish between the following two angles:.
1 experimental group the result is not known before, only to know through experiments. the group is known to themselves, do not know the test of common sense.
2 results experimental and control groups affected by many variables shall study carried out by "control of variables." follow variable single principle, i.e. to ensure that
different only variable inquiry, the other amounts to the same, and suitable to eliminate the influence of other variables of the experimental results the following are three common control where
① blank control: i.e. a group containing no variable processing experiments, experiments to test group containing variable processing
② own control: It refers to the experimental and control groups were performed on the same subjects as plasmolysis and recovery experimental observation of plant cells, the control group or normal onion epidermal cells and experiment i.e. plasmolysis and recovery of cells of the same group of cells , is a typical self-control experiment
③ each control: a control group not individually, but several of each experiment as a control "Comparative catalase Fe3 + and catalytic efficiency" experiments, respectively catalase and Fe3 + to the catalytic decomposition of hydrogen peroxide, for each comparison, to derive conclusions enzyme efficiency and the like.