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…

Potash, an essential raw material of the 18th century, used to be produced from the ashes of plants. Known since antiquity, it was in 1807 that Humphry Davy put an end to the decades-long controversy about its nature as a compound. The technology behind potash production was implemented in Brazil by the Portuguese naturalist Frei Velloso. The…

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…

Old physics textbooks give us a great opportunity to learn about the history of science and rediscover different methods to teach physics to our students. There are many disused and forgotten experiments in them, but these can still be very useful to affirm and understand physics. This is the case of an instrument used in the 19th century to…

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…

Michael Faraday is considered one of the greatest science lecturers in history. He popularized the Christmas Lectures as a format of science communication that has survived until today in the Royal Institution of Great Britain. Especially, his "Chemical History of a Candle" has become a classic of science communication that has inspired…