Each year, 6th grade students experiment with simple machines and the concept of mechanical advantage. After learning about the 6 simple machines and examining the work formula (Work =Force x Distance), we measure the number of students that it takes to tow my full size pick-up truck up a hill without any mechanical advantage. Normally, it takes 8 or 9 students.

We set up a pulley system and measure how many students it takes using the simple machine. This normally requires as few as 2 students. Next, we calculate the mechanical advantage (the factor by which forces are reduced in a simple machine). Since the number of students was reduced by a factor of four or five, we estimate the the mechanical advantage of the pulley system is about four or five. We also measure the change in distance between the truck’s motion and the amount that the rope moves with the pulley. This will again give us around four times more distance for the rope than the truck. Students always like the activity, and even though we do accomplish scientific Work, it doesn’t really feel like school work (ba dump tsss).

Mark Pendergrass
Middle School Science Teacher