In this unit students have been exploring how contact forces cause damage in a collision. As a culmination project, students undertook an engineering design challenge to address the problem of concussions in competitive cheerleading. They explored how materials provide different cushioning properties and some of the criteria and constraints they would face in their design. They presented their proposed solution and developed a prototype of their model. To test their designs they built their prototype and testing its effectiveness by its ability to cushion an egg during a fall.