The Yavneh Academy seventh graders built a Human Body Expo—interactive models of two body systems out of recycled materials. They presented the models to early childhood students who have been learning about the body systems. The early childhood students enjoyed their tours through the expo. They put marbles down an esophagus, completed circuits to send a signal through the nervous system and pulled strings to contract muscles. The seventh graders shared their knowledge of how the body systems work together.