Teaching energy: a systems approach

The systems approach to teaching energy for 15-16-year-old students in a recently published Dutch physics textbook (Licht et al 1990) is characterized by the definition of a system and the study of energy exchange between the system and its environment. The energy exchange is visualized in an energy-budget diagram showing input energy, output energy and the change in energy content of the system. Strengths of the approach are (a) the use of energy as a unifying concept linking various branches of physics, (b) the power of the method in provoking rather fundamental questions from students and (c) a consistent approach to problem-solving. Weaknesses are (a) students do not immediately use the method correctly - they have to be trained in it explicitly, and (b) the method raises some physics questions that are above the level of the students. However, this problem has been overcome through acceptable simplifications.