All bodily functions, from thinking to lifting weights, to sleeping, require energy. For example, in addition to lifting patients and heavy supplies, an RN like Jolene will walk several miles over the course of working a 12 hour shift on the MED floor.  Energy is defined as the capacity to do work, such as lifting objects moving our bodies, and so by the end of  a shift Jolene feels tired because doing work has depleted her body’s energy stores. Any time that work is done, energy must be transferred from one category of energy to another, and/or from one object to another, but energy can never  appear or disappear. The previous statement is the Principle of Energy Conservation. In this unit we will use energy conservation to study the balance of energy in the body and other systems. The associated lab will guide us through an analysis of  forces on the body during a vehicle collision and how crumple zones are designed to reduce those forces. The learner outcomes for this unit are listed below, and below that are some related key terms to watch out for as you complete the chapter.