Energy is a central concept in physics. Because energy is conserved, it is possible to understand the behavior of complex systems by tracing the flow of energy through them. On the other hand, we humans “consume” energy, degrading it into less useful forms, as it powers modern societies. Providing energy for the world to use in a sustainable fashion is a major, perhaps existential challenge for humankind in the 21st century. The scale and scope of the problem is enormous. The implications for Earth and human societies are profound.
Economic considerations and political decisions will be central to any attempt to address this energy challenge. However, decisions made in the absence of good scientific understanding have the potential to waste vast amounts of effort and resources and to adversely affect countless lives and large ecosystems. A clear understanding of the science of energy is essential for specialists and non-specialists alike. Physicists and our universities have an opportunity, even a responsibility to provide this understanding.
In response to this challenge, Washington Taylor and I developed a physics course for MIT undergraduates and an associated textbook — “The Physics of Energy” –– that focus on the sources and uses of energy, and on energy systems and the externalities associated with energy use, including climate change. After setting out the nature of the problem, I will describe the motivation for and structure of an energy-centered university physics course for students with a strong science and math background, illustrate the topics it covers, and relate some of the insights that we uncovered along the way.