Block and Tackle Experiment
This simple apparatus shows how blocks and tackles increase power. You need two lengths of broomstick and a length of clothesline. Fasten one end of the line to one of the sticks. Wrap line loosely around both sticks as shown. Have two of your biggest den members grasp the sticks and try to keep them apart while the smallest den member pulls on the line. He should be able to pull the sticks together no matter how the others try to keep them apart.