Simple Machines: Pulleys

 One morning, one of the boys noticed that there were a couple of round things hanging from the crossbar on the sensory table. 
"What are those things?" he asked.
"Those are called pulleys," I said. "They are one of the things that make work easier for us. Do you want to see how they work?"
"Yeah," he said.

Soon we were joined by a few other inquiring preschoolers. We go some yarn to thread through the pulleys and we put it around one of the big, long hollow blocks. I showed them how to use it to make the block go up. The kids decided to add some of the sorting animals inside the block.

"It's just like an elevator," one student said. I told them this was a similar system to the one that elevators use to go up and down.