The January 2013 Physics Challenge for Teachers and Students has some features that are surprising and worth a closer look. The problem concerns a Carnot-cycle refrigeration unit operating inside a tent. It achieves dynamic equilibrium with a freezer ("cold") compartment temperature of T[subscript C] = 13°C, tent temperature of…

In 2009, President Obama proposed an initiative to decrease our country's energy consumption and dependence on fossil fuels. One key to this plan was to decrease the amount of energy used to heat and cool our homes through government incentives. The EPA estimates that the average American household spends over $1000 annually for heating and…

Al Bartlett's video "Arithmetic, Population, and Energy" spells out many of the complex issues related to energy use in our society. Bartlett makes the point that basic arithmetic is the fundamental obstacle preventing us from being able to grasp the relationships between energy consumption, population, and lifestyles. In an earlier…

Energy Theater is a dynamic, full-body activity that engages all students in representing the flow of energy in various phenomena, such as a light bulb burning steadily or a refrigerator cooling food. In Energy Theater, each participant acts as a unit of energy that has one form at a time. Regions on the floor correspond to objects in a physical…

Going "green" is a slogan that is very contemporary, both with industry and in the political arena. Choosing more energy-efficient devices is one way homeowners can "go green." A simple method is to change home lighting from hot incandescent bulbs to compact fluorescent lights (CFLs). But do they really save energy? How do their illuminations…

The scientific method is arguably the most reliable way to understand the physical world, yet this aspect of science is rarely addressed in introductory science courses. Students typically learn about the theory in its final, refined form, and seldom experience the experiment-to-theory cycle that goes into producing the theory. One exception to…

Most likely, solar cells will play a significant role in this country's strategy to address the two interrelated issues of global warming and dependence on imported oil. The purpose of this paper is to present an explanation of how solar cells work at an introductory high school, college, or university physics course level. The treatment presented…

Throughout North America the curriculum of introductory physics courses is nearly standardized. In 1992, Tobias wrote that four texts dominate 90% of the introductory physics market and current physics education research is focusing on how to sustain educational reforms. The instructional team at the University of British Columbia (UBC) recently…

The hybrid automobile is a strikingly new automobile technology with a number of new technological features that dramatically improve energy efficiency. This paper will briefly describe how hybrid automobiles work; what are these new technological features; why the Toyota Prius hybrid internal combustion engine operates on the Atkinson cycle…

An introductory approach to black holes is presented along with astronomical observational data pertaining to the presence of a supermassive black hole at the center of our galaxy. Concepts of conservation of energy and Kepler's third law are employed so students can apply formulas from their physics class to determine the mass of the black hole…

Energy concepts are fundamentally important for describing and analyzing systems ranging from subatomic particles to spiral galaxies. In general, students first encounter such concepts in introductory courses that typically focus on forms of energy, energy transfer, and conservation laws. Within these courses, conservation of mechanical energy is…

The standard formulation of energy conservation involves the subsidiary ideas of kinetic energy ("KE"), work ("W"), thermal energy, internal energy, and a half-dozen different kinds of potential energy ("PE"): elastic, chemical, nuclear, gravitational, and so forth. These quantities came to be recognized during the centuries over which the…

Discusses Newton's apparent oversight of the role of energy considerations in collisions between two spherical bodies related to the third corollary of his "Laws of Motion." Investigates several theories that provide solutions to the mysterious oversight. (LZ)

Comments on a news item on rail traffic that is meant to promote conservation of energy. (GA)

Discusses the potential and feasibility of future widespread exploitation of the vast geothermal energy resources, that could greatly reduce the need for other forms of energy resources. (GA)