A “shocking” fish The common torpedo, or eyed electric ray, is a species of fish found in the Mediterranean Sea and the eastern Atlantic Ocean. It has an unusual capability of stunning its prey, with what we now understand to be an electric shock. The torpedo was known to ancient Greeks and Romans who believed … Continue reading The Mystery of the Torpedo Fish and the Concept of Voltage
Today I thought of writing about a rare history-of-science book that I have in my collection. Wilhelm Ostwald, after whom the nitric acid manufacturing process is named, wrote an exhaustive history of electrochemistry in 1896. The book was in German, and was titled Elektrochemie, ihre Geschichte und Lehre (Electrochemistry: its History and Teaching). I came … Continue reading Ostwald’s “Electrochemistry: History and Theory”
William Beaumont’s experiments on his patient Alexis St. Martin’s stomach in the 1820s are probably well known. St. Martin’s gunshot wound left him with a hole in the stomach that wouldn’t close. Moreover, it formed a fistula with the skin as the wound healed, which meant that he was left to live with a direct … Continue reading A Window into the Stomach: Dr. Beaumont’s Experiments with the Gastric Juice
The experimental set-up A common experiment done in high school is to verify Ohm’s law. Ohm’s law, or rather one part of it, states that the current through a resistance is directly proportional to the difference in potential (voltage) between its two ends. The diagram below represents the circuit that is often used for verifying … Continue reading The Circular Reasoning of “Verifying” Ohm’s Law in School
A short paper titled “Circumstances affecting the Heat of Sun’s rays” appeared in the 1856 edition of the American Journal of Science and Arts. It was only a page and a half long, and had a brief and crisp description of three experiments. Effect of density The first one studied how the warming of air … Continue reading Eunice Newton Foote: the Woman who Foresaw Global Warming
In the introduction to his book Rediscovering Optics, physics educator and history of science scholar Nahum Kipnis lucidly summaries what he considers to be the main benefits of a historical-investigative approach to science teaching – an approach in which historical experiments are repeated and the findings reconstructed by the students. I paraphrase them below. 1. … Continue reading Nahum Kipnis on the 7 Benefits of a Historical-Investigative Approach to Science Teaching
A. K. T. Assis is a Brazilian scholar who has written some intriguing books on physics and the history of physics. He has very generously made all these books available for free access on his website – https://www.ifi.unicamp.br/~assis/books.htm. I have been flipping through the book Ampere’s Electrodynamics by Prof. Assis. It requires a much closer … Continue reading Ampere’s Alternate Interpretation of Electromagnetism
Two Faradays and two electromagnetic discoveries Michael Faraday is one of the most well known names in science, probably even for people outside science. He made two landmark discoveries which led to the invention of the electric motor and the electric generator — two devices which we benefit from, every single day of our lives. … Continue reading When Young Faraday’s First Discovery Led to Charges of Plagiarism
Read the previous parts if you haven’t: Part 1 Part 2 In the previous article, I briefly introduced the major developments in the knowledge of electricity up to the first half of the 17th century. So, what lessons and activities for the classroom can be designed based on this? I intend to describe one possible approach … Continue reading Electrostatics in Middle-School – Part 3: Early Electrical Knowledge in the Classroom
Read Part 1 if you haven’t. Amber and Lodestone Since antiquity, people have been fascinated and mystified by rare materials with special properties. Two such materials were amber — a fossilised resin from extinct pine-like trees — and lodestone — an iron-containing mineral that we now recognise as permanently magnetic. The ancient Greek (4th century … Continue reading Electrostatics in Middle School – Part 2: Early Knowledge of Electricity
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