# I did this science experiment in class where we tested substances for sugars and starch. We had twelve test tubes, divided into six and six. Both halves were labeled with numbers 1 through 6. All...

I did this science experiment in class where we tested substances for sugars and starch. We had twelve test tubes, divided into six and six. Both halves were labeled with numbers 1 through 6. All test tubes had 20 drops of distilled water. The corresponding numbers had the same substance. For example, #1 had 15 drops of sugar solution each, #2 had 1/2 scoop of potato buds each, #3 had 1/2 a ripped up marshmallow each, #4 had 1/2 a scoop of powdered eggs each, #5 had 1/2 a scoop of corn starch, and #6 only had the original 20 drops of distilled water.

We put 3 drops of Lugol's solution each into the first 6 test tubes to test for starch. We put 5 drops of Benedict's solution each into the remaining 6 test tubes each to test for sugar. We put the test tubes with the Benedict's solution into a large beaker with 250 mL of water and we put it on a hot plate to heat it. We were watching for the colors of the test tubes. With the Lugol's, purple or black meant there was starch. With Benedict's, any color other than blue meant there was sugar.

I was wondering what the control in this experiment is? Is it the amount of distilled water, the solution that was put into the test tube(Lugol/Benedict), or something else?