At constant current (I) the forward bias potential (V) of a "pn" junction diode may be considered to vary linearly with temperature (t) within a temperature range. Based on this property we have constructed diode thermometer using germanium (Ge) and silicon (Si) diodes. The experimental "V-t" data at constant forward current…

A common misconception about dissolving is that heating and/or stirring are required for the dissolving process to occur. In this study, quantitative experimental evidence was collected and analyzed to demonstrate that neither heating nor stirring is required for dissolving. Educators can use the data and results in this study to address this…

In the present theoretical study, we introduce the entropy concept into Chi's ontological shift theory. Chi distinguishes between two categories of process phenomena, direct and emergent, and claims that incorrectly considering emergent processes as direct ones is one of the sources of students' robust scientific misconceptions. The present study…

This article describes our modeling approach to teaching the one-dimensional heat (diffusion) equation in a one-semester undergraduate partial differential equations course. We constructed the apparatus for a demonstration of heat diffusion through a long, thin metal rod with prescribed temperatures at each end. The students observed the physical…

Flipped classrooms support learner-centered approaches to improve conceptualization, comprehension, and problem solving skills by delivering content outside the classroom and actively engaging students inside the classroom. While literature in engineering and science education supports and encourages the use of inverted instruction, many core…

An alloy is an intimate association of two or more metals, with or without a definite composition, which has metallic properties. Heterogeneous alloys, such as tin-lead (Sn/Pb) solders, consist of a mixture of crystalline phases with different compositions. A homogeneous alloy with a unique composition having the lowest possible melting point is…

In order to interpret laboratory experimental data, undergraduate students are used to perform linear regression through linearized versions of nonlinear models. However, the use of linearized models can lead to statistically biased parameter estimates. Even so, it is not an easy task to introduce nonlinear regression and show for the students…

The physics and chemistry education literature has grappled with an appropriate definition for the concept of heat for the past four decades. Most of the literature promotes the view that heat is "energy in transit" or "involves the transfer of energy" between the system and surroundings because of a difference in temperature. Given that many…

Some peculiarities of the heat transfer through a sample that is heated by the superficial absorption of light energy under continuous uniform illumination are discussed. We explain, using a different approach to that presented in a recent article published in this journal (Salazar "et al" 2010 "Eur. J. Phys." 31 1053-9), that the front surface of…

In this study, a Thermodynamic Concept Test (TCT) was designed to assess student's conceptual understanding heat and thermodynamics at undergraduate level. The different statistical tests such as item difficulty index, item discrimination index, point biserial coefficient were used for assessing TCT. For each item of the test these indices were…

A microwave-assisted synthesis of "N"-phenylsuccinimide has been developed for the second-semester organic teaching laboratory. Utilizing this procedure, "N"-phenylsuccinimide can be synthesized in moderate yields (40-60%) by heating a mixture of aniline and succinic anhydride in a domestic microwave oven for four minutes. This technique reduces…

Substitution reactions, a central part of organic chemistry, provide a model system in physical chemistry to study reaction rates and mechanisms. Here, the use of inexpensive and readily available commercial conductivity probes coupled with computer data acquisition for the study of the temperature and solvent dependence of the solvolysis of…

Heat and thermodynamics is a conceptually rich area of undergraduate physics. In the Indian context in particular there has been little work done in this area from the point of view of misconceptions. This prompted us to undertake a study in this area. We present a study of students' misconceptions about heat transfer mechanisms, i.e. conduction,…

Here, we propose a simple method for measuring the built-in potential and its temperature dependence of a photodiode by a photosaturation technique. The experimental design facilitates both current-voltage and null voltage measurements as a function of white light intensity. This method gives the built-in potential directly; as a result its…

This paper focuses on the determination of the final equilibrium state when two ideal gases, isolated from the exterior and starting from preset initial conditions, interact with each other through a piston. Depending on the piston properties, different processes take place and also different sets of equilibrium conditions must be satisfied. Three…