Physics and chemistry students learn several methods to determine the density of materials. While measuring the mass of materials is usually simple, volume measurements are more complex. For simple shapes the volume may be determined by measuring its geometry; for more complex shapes students often use Archimedes' principle. However, neither of…

Two bodies initially at different temperatures gathered into an isolated container exchange heat and reach an equilibrium state with a common final temperature. During the process, the system is out of equilibrium and its intermediate temperature is not well defined. By conceiving a quasi-static process with infinitesimal steps from the initial to…

Project-based learning has been shown to be an effective pedagogical strategy that motivates students and thus promotes learning. In this article we describe a project-based unit centered on the physics of solar cookers (Fig. 1 and 3). Our goal was to elevate the solar cooker from a summer camp activity to a college-level project that could be…

What follows is a description of several activities involving the Stefan-Boltzmann radiation law that can provide laboratory experience beyond what is normally found in traditional introductory thermodynamics experiments on thermal expansion, specific heat, and heats of transformation. The activities also provide more extensive coverage of and…

The literature has revealed that many students encounter substantial difficulties in applying the first law of thermodynamics. For example, university students sometimes fail to recognize that heat and work are independent means of energy transfer. When discussing adiabatic processes for an ideal gas, few students can correctly refer to the…

On Dec. 27, 2006, we drove with our children and their families to a cabin we rented on the grounds of the "YMCA of the Rockies" in Estes Park, CO, for a few days of winter relaxation and recreation. On the night of the 27th a snowstorm dropped over half a meter of new snow, creating a beautiful winter wonderland. For the next couple of days the…

When most materials are heated they expand. This concept is usually demonstrated using some type of mechanical measurement of the linear expansion of a metal rod. We have developed an alternative laboratory method for measuring thermal expansion by using a Michelson interferometer. Using the method presented, interference, interferometry, and the…

Energy is a critical concept that is used in analyzing physical phenomena and is often an essential starting point in physics problem-solving. It is a global concept that appears throughout the physics curriculum in mechanics, thermodynamics, electromagnetism, and modern physics. Energy is also at the heart of descriptions of processes in biology,…

A pair of fine tweezers and a steady hand may well be enough to pick up a grain of sand, but what would you use to hold something hundreds of times smaller still, the size of only one micron? The answer is to use a device that is not mechanical in nature but that relies instead on the tiny forces that light exerts on small particles: "optical…

Discusses the difficulties with the standard model for introduction of attractive forces into the van der Waals equation. Presents an analysis in terms of force and time delays and an alternative analysis for more advanced students in terms of energy. (JRH)

Describes the working of the Adiabatic Gas Law Apparatus, a useful tool for measuring the pressure, temperature, and volume of a variety of gases undergoing compressions and expansions. Describes the adaptation of this apparatus to perform isothermal measurements and discusses the theory behind the adiabatic and isothermal processes. (JRH)

Demonstrates misconceptions of the meaning of temperature based on classical kinetic energy. Discusses some misconceptions about negative temperatures and the effect of compression. (YP)

Discusses interesting aspects of the Carnot cycle and other thermodynamic cycles that are generally not dealt with in elementary physics texts. Presents examples that challenge the student to think about the extraction of net work from a cycle. (JRH)

Reviews "Thermodynamics" (Cross Educational Software) and "Calorimetry and Thermodynamics" (Educational Materials and Equipment Company). The first package has seven programs (briefly described) while the second package contains virtually an identical subset of the Cross package. (JN)

Describes experiments designed to investigate the cooling rate of microwave-boiled water as compared to that of stove-boiled water. Concludes that within experimental limits, microwave-boiled water and stove-boiled water cool at the same rate. (JRH)