Energy is a fundamental physical element, which can be defined simply as: the capacity of a body or system to accomplish "work." Work is defined as: the result of a force being applied over some distance. As such, work can be accomplished in various ways, as is illustrated by the following examples: (a) a baseball bat strikes a ball, causing it to fly though the air; (b) an engine transforms energy of gasoline into motion of a drive-shaft, allowing an automobile to be driven along a highway; (c) heat from a stove is absorbed by water in a kettle, causing it to boil, and (d) the pigment chlorophyll absorbs sunlight, converting its energy into a form that plants and algae can use to manufacture simple sugars through photosynthesis. In each of these cases of "work," energy has been transformed from one state to another, and a measurable outcome...