Energy conversion devices such as fuel cells, metal-air batteries, and electrolyzers have been envisaged as possible solutions for cutting down the continuous accumulation of greenhouse gases resulting from the combustion of fossil fuel. The bottleneck reaction for these devices is the oxygen reduction reaction (ORR) occurring at the cathode. The…

Historically, classical thermodynamics was developed during attempts to improve the efficiency of steam engines. Those investigations led to the well-known zeroth, first, and second laws of thermodynamics. Although these laws are presented independently, linkages between the zeroth and second laws have been pointed out in the physics teaching…

Breathing is something we all do, usually without thinking about it. But when viewed through the lens of physics, respiration becomes an example of elementary thermodynamics. As shown here, the lungs can be modeled as a two-stroke heat engine. Breathing thereby provides a novel physics application for life science students, demonstrating the…

The change in enthalpy of a chemical reaction conducted at constant pressure is equal to the heat of the reaction plus the nonexpansion work of the reaction, ?H = qP + w[subscript additional]. After deriving that relationship, most general and physical chemistry textbooks set w[subscript additional] = 0 to arrive at the claim that ?H = qP, and…

Physical principles are involved in almost any aspect of cooking. Here we analyse the specific process of baking pizzas, deriving in simple terms the baking times for two different situations: for a brick oven in a pizzeria and a modern metallic oven at home. Our study is based on fundamental thermodynamic principles relevant to the cooking…

The article proposes a new research object for a general physics course--the vapour Cartesian diver, designed to study the properties of saturated water vapour. Physics education puts great importance on the study of the saturated vapour state, as it is related to many fundamental laws and theories. For example, the temperature dependence of the…

Using everyday life examples is proven didactically useful for teaching physics, as it presents effective applications of physical laws. Cooking and food, in particular, serve two useful purposes: on one side, they are able to engage students in the study of physics with familiar examples; on the other side, thanks to the wide range of physical…

The argument that the second law of thermodynamics contradicts the theory of evolution has recently been revived by anti-evolutionists. In its basic form, the argument asserts that whereas evolution implies that there has been an increase in biological complexity over time, the second law, a fundamental principle of physics, shows this to be…

Small organic molecules offer a rich opportunity to discuss the interplay of chemical structure with properties such as the melting point and phenomena such as glass formation and can form the basis of fundamental considerations of structure-property relationships in macromolecules. Of particular importance are thermal transitions, specifically…

Comfort whilst camping overnight during outdoor pursuits is based on pain free and warm sleeping arrangements and is highly dependent on the performance of the sleeping bag and sleeping mat. In adventurous and challenging situations, performance can contribute to safety and expedition success. From the manufacturer's point of view, thermal…

When carbonated beverages (which are supersaturated solutions of aqueous carbon dioxide) are confined within a narrow-necked container, events which rapidly release the gas from solution produce a fountain out of the beverage. One well-known variant of this experiment is the addition of Mentos candies to a bottle of Diet Coke. Previous reports…

The enthalpy of vaporization (?H[subscript vap]) of salt solutions is not easily measured, as a certain quantity of pure water has to be evaporated from a solution, at constant composition, and at a fixed temperature and pressure; then the corresponding heat input has to be measured. However, a simple bubble column evaporator (BCE) was used as a…

It is well known that heat transfer between two objects results in a positive change in the total entropy of the two-object system. The second law of thermodynamics states that the entropy change of a naturally irreversible process is positive. In other words, if the entropy change of any process is positive, it can be inferred that such a process…

Flooded heat exchangers are often used in industry to reduce the required heat-transfer area and the size of utility control valves. These units involve a condensing vapor on the hot side that accumulates as a liquid phase in the lower part of the vessel. The heat transfer occurs mostly in the vapor space, but the condensate becomes somewhat…

A highly instructive, wide-ranging laboratory project in which students study the effects of various parameters on the enzymatic activity of alcohol dehydrogenase has been adapted for the upper-division biochemistry and physical biochemistry laboratory. Our two main goals were to provide enhanced data analysis, featuring nonlinear regression, and…