My son's science project was supposed to demonstrate a control group. He put two identical plants on the windowsill. He watered both. He talked to one. He presented it to the class. He said, 'The plant I talked to grew two centimeters taller.' The teacher said, 'What variable did you control?' He said, 'I controlled the talking. I only talked to one. The other one had to sit there and not get talked to. That was the control. The control was silence. The control was the plant being ignored. I feel a little bad about the control group.'