George M. Hopkins (1842-1902) wrote a series of articles on demonstrating physical phenomena in the "Scientific American" during the last years of the 19th century. These were collected in a book, "Experimental Science," that was first published in 1890, with revisions in 1892 and 1902. It must have been well received, for the…

In this article, we discuss the replication of a forgotten chemical instrument in the context of undergraduate chemistry education. Together with students, we have attempted to replicate an eighteenth century "eudiometrical" procedure. Eudiometry was the practice of measuring the "goodness" of the air by looking at the volume…

Cell size is an important variable in the study of cellular growth, metabolism, and the cell cycle. The large size of "Amoeba proteus" and the ease with which it can be collected and cultured have made it a star in biology education--and it was a model for research on cell biology before the introduction of molecular genetic methods.…

It is well known that Newton's work on mechanics depended in a crucial way on the previous observations of Galileo. The key insight of Galileo was that one can analyze the motion of bodies using experiments and mathematical equations. One experimental observation that roughly emerges from this work in modern terms is that two objects of different…

A popular introductory physics laboratory experiment is one focusing on Snell's law. This is straightforward to complete with lasers and prisms, but here we present an alternative version that guides the students through some of the major historical developments, recreating and analyzing significant experiments. The discovery of Snell's law has a…

Over 200 years ago, Alessandro Volta published his observations of a steady voltage when a piece of electrolyte-soaked cardboard was sandwiched between two dissimilar metals. This observation initiated a century of argument as to the origin of voltaic electricity (contact vs chemical) and catalyzed practical advances, such as the first…

The five papers published by Hodgkin and Huxley in 1952 are seminal works in the field of physiology, earning their authors the Nobel Prize in 1963 and ushering in the era of membrane biophysics. The papers present a considerable challenge to the novice student, but this has been partly allayed by recent publications that have updated the…

Joseph Priestley, discoverer of oxygen, lived in Nantwich, Cheshire, UK, from 1758 to 1761. In 2019, an exhibition featuring his life and achievements, and also celebrating the International Year of the Periodic Table, was developed by the Nantwich Museum. The historical research of Priestley's life, development of the exhibition, and rationale…

Student understanding of the laws that describe the flow of a fluid is often hampered by a defective knowledge of basic classical mechanics (kinematics, statics, dynamics, and conservation laws) and by wrong common-sense ideas about quantities related to fluids, such as velocity and pressure. A pedagogical discussion about the Venturi effect,…

An apparatus of the 70s for measuring thermal conductivity in different materials is used to visualize, through an infrared thermal imaging approach, temperature fields and the heat diffusion process. The observed temperature profiles also suggest solid grounds for a fair mathematical modelling of this phenomenon.

In the modern and exciting world of particle physics, in which scientists talk of Higgs bosons and supersymmetry, it would be natural for someone to dismiss the common proton as a particle too pedestrian to be interesting. Yet in the centennial year of the announcement of its discovery, studies of the humble nucleus of the hydrogen atom continue…

In 2018, we celebrated the sesquicentennial birthday of Robert A. Millikan, a Nobel laureate in physics who worked among the greats such as Niels Bohr and Albert Einstein. His name, however, is perhaps not as widely known. He was born in 1868 in Morrison, Illinois, and moved with his family to the small town of Maquoketa, Iowa, at age nine. It was…

Ask a physics person what the name of Robert A. Millikan brings to mind, and most would immediately think of the eponymous experiments that he did with the charge on the electron in the years 1908 to 1913. A few might remember his work, starting in 1914, with the experimental determination of Planck's constant using the photoelectric effect. Few…

Winston Churchill once said of Russia that it was a riddle wrapped in mystery inside an enigma. Were the British Bulldog a physicist, he might have been talking of something other than our Slavic comrades. He might have been talking about an electron. This article covers the more modern representations of the electron. A brief reminder of the…

As is true of a far more famous story, it all began a long time ago, in a galaxy far, far away. It even involved a binary star system. A small star, called a white dwarf, had become a burned out husk of its former self and it turned to gorging on hydrogen and helium from its bloated red giant neighbor. The transferred gas reignited the fires of…