It's all about designing a process to follow so that we can be confident about what we believe. The scientific method is a way of thinking and conducting.1) The control group is our standard. It's what we know. It's to what we compare something.
2) The blind experiment is exactly what it sounds like. Certain parties are made ignorant of part or all of an experiment. If we are testing whether or not Coke tastes better than Pepsi we cover the cans in paper so the taster doesn't know which is which. If we are testing a new medicine, we keep the patient and the person administrating the medicine from knowing whether they are handling the placebo or the real thing. The blind experiment is an attempt to eliminate bias.