Biomaterial science is a rapidly growing field that has scientists and doctors searching for new ways to repair the body. A merger between medicine and engineering, biomaterials can be complex subject matter, and it can certainly capture the minds of middle school students. In the lesson described in this article, seventh graders generally learn concepts such as systems in living things, properties of matter, and bioengineering technologies as they relate to adaptive and assistive technologies. In this article, two classes of seventh-grade students were given the task of repairing a 15-year-old boy's broken femur. (Contains 4 figures and 5 online resources.)