I haven't been lurking for awhile.. but I'm back with a couple of questions.

 

Q1: What is a "control" sample?

Q2: Why is it important to have "controls" in your experiment?

 

I do roughly know what a control sample is, but I need the proper definitions. Your help would be greatly appreciated.

'Control samples' are the basis of experimental method.

 

When you're doing an experiment, you're basically testing what changing one variable has on a subject. For example, you could be testing how differently coloured light affects the rate of photosynthesis in plants.

 

You do this test (say, shining blue light at a fern) and you get your results. What do they mean?

 

This is where the control comes in.

 

The control sample is one which has all the conditions from the test, except the one your are testing. So, in the example, for the control you have white light, or no light, shining on it (depending on how you want to work the test). It's basically the thing you're testing in it's vanilla state.

 

Without having a control sample, the experiment is meaningless, because you cannot know whether the data you have gathered was a result of the thing you are trying to test, or whether something in the setup of the experiment caused it. With a control sample, you have a base to compare with.

Got it. Thanks man