After he explained all the stations, he had the children divide into groups. He had an obstacle course laid out for the children to guide a storage tote filled with heavy books around the room. They had to only use simple machines to get the tote from one side of the room to the other.
Using a wheel and axle with a lever to move the tote across the floor.
Pulling the rope on the pulley system to move the tote.
This was wonderful exercise to have the children work together and use critical thinking during the obstacle course. They all had a wonderful time.