Intended to supplement undergraduate college geography courses, this resource paper investigates several concepts which are prerequisite to the study of physical geography. The student is provided with a "systems" approach to physical geography, which combines the underlying principles of physics with the contextual application of these principles to the specific domain of physical geography. The particular framework introduced is based upon the idea that nature tends to remain in steady states through the action of internal regulation mechanisms known as feedback. The underlying physical principle is one of conservation: the conservation of mass, energy, and momentum. Examples are given to illustrate these conservation laws and how they ultimately account for the weather and erosion. The general circulation of the atmosphere is described and provided as an explanation for climatic conditions, such as precipitation and wind effects. Fluvial erosion is presented as another example of feedback operations, in which energy is traced from its source in the atmosphere through a number of steps to stream flow. (Author/MLH)