A negative control is a control group in an experiment that uses a treatment that isn’t expected to produce results. A positive control is a control group in an experiment that uses a treatment that is known to produce results.Click to see full answer. Then, what is the purpose of a positive control?A positive control is a group in an experiment that receives a treatment with a known result, and therefore should show a particular change during the experiment. It is used to control for unknown variables during the experiment and to give the scientist something to compare with the test group.Subsequently, question is, what is a positive control example? A positive control group is a control group that is not exposed to the experimental treatment but that is exposed to some other treatment that is known to produce the expected effect. As a positive control, you might swab an existing colony of bacteria and wipe it on the growth plate. Just so, what is the difference between a positive and a negative control? It can be defined as an experiment that is designed to minimize the effect of variables other than the independent variables. The main difference between positive and negative control is that positive control gives a response to the experiment whereas negative control does not give any response.What is positive and negative control in microbiology?The positive control is an experiment that involves the repetition of the test using working treatment. On the other hand, a negative control is an experiment in which the microbiologist knows that there will be a negative outcome. In the negative control, the microbiologist does not expect any response.