What is the function of a control group in an experiment?
The function of a control group in an experiment is to be a stable to account for any effects a given environment has on variables in your experimental group. The control group isolates any uncontrollable phenomena by not being subjected to the unknown variable being tested. The most powerful experiments have two types of control groups a positive and negative control group. A positive control group is subjected to conditions, which are known to make a positive result to show your experiment is working as expected. A negative control group is subjected to conditions where a negative result is expected. Both of these controls can then be compared to your experimental group to quantify the effect your unknown variable has relative to your controls.