The Teacher Michael
1970s and 1980s
Hi! My name is Michael* and I am a physics teacher at a high school in Sarstedt. Back in 1972, I attended an introductory lecture on experimental physics in Göttingen and was fascinated by the lively demonstrations I saw. I intend to pass this enthusiasm on to my students until I retire in 2015—in fact, you will see how I try to keep these exciting experiments alive through my teaching. The three-volume textbook authored by Robert W. Pohl has been a close companion since my student days, and I often use it to help prepare for my classes. Pohl’s first edition appeared in 1927, and he updated it constantly, adding new experiments until the end of his life in 1976. I’ve heard that this textbook fundamentally changed the way schools and universities teach physics…but more on that later.
*Michael is a fictional character based on the retired physics teacher Dr. Michael Barth.
I can always find useful, interesting ideas and experiments in Pohl’s textbook to help me teach physics in high school. He did a great job, writing a school book that is immensely useful to both students and teachers. This certainly helps explain its popularity, as well as its straightforward, clear approach to making complicated concepts visible—and presentable—in the classroom. However, some experiments require hours of preparation, and only make sense in a larger lecture hall. From time-to-time, I tell my students what it was like to attend these wonderful lectures.
As part of the research project “Projections: The Teaching Collection of Robert Wichard Pohl”, Dr. Michael Markert conducts an interview with physics teacher Dr. Michael Barth.
“That was my ‘go-to’ book for experimental physics.” “Really?” “Yes! I studied it intently for two years, used it to prepare for my University exams, and keep referring to it even now because, in my opinion, it explains physics in a clear, simple way that makes it a very useful tool for teaching at the secondary school level…”
“In one lecture—it must have been Professor Gründig—we were shown on the blackboard how a boomerang flies. That’s a pretty complicated topic, with torque forces, conservation of angular momentum and aerofoil dynamics and angle of attack and the Bernoulli vacuum principle. He completely dissected the entire concept of a boomerang, including how to throw it, how it returns to its point of origin and so on. Then, he reached down under the podium and pulled out a boomerang…a really BIG boomerang! He held it up to his audience and said, ‘Here, I’ll show you again…’, this time explaining with the actual device in-hand, indicating where the vectors are, how to hold it properly, ’…and when we throw it, it spins through the air and returns exactly as I’ve explained.’ And then I remember him saying: ‘Students up there, under the ceiling lights, please pay attention.’ Suddenly, he wound up and launched this huge boomerang out into the lecture hall, sent it flying over the heads of his audience in a great soaring loop and, when it finally whirled back to the stage, snatched it out of thin air! I have never seen anything like it.”
“In my classes, I often recount these experiments—the transformer, the boomerang, or some other impressive demonstration—to make the point: I was THERE! By doing so, I hope to convey my enthusiasm not just for the experiments themselves, but also to show my students how wonderful and interesting it is to study physics.”
“Of course it’s a circus, but it’s a circus with a function.”
An excerpt from Pohl’s 1953 textbook on mechanics, acoustics and thermodynamics shows how illustrations were employed to help describe physical phenomena.
Pohl’s textbook Introduction to Physics was an internationally recognized “gold standard” in its field for many decades, and remains in wide circulation today. Shortly after publication of the first edition, it was already referenced in English-language specialist journals, and soon thereafter was translated into English, Italian, Russian and even Marathi, a language widely-spoken in India. While Pohl’s textbook was well received in many parts of the world, his shadow projection technique was seen mostly in German universities.
Professor Pohl constantly updated and refined his textbook, sometimes extensively, until his death in 1976. Since his passing, subsequent editions have been produced by his son Robert Otto Pohl, also a professor of experimental physics. Together with other experts, Robert O. Pohl has produced more than 60 short films demonstrating the most important experiments from his father’s lectures and publications—converting Pohl’s original “shadow plays” into digital form and transforming them from black & white to full-color. Included with recent editions of the Introduction to Physics textbook, these demonstrations can also be viewed virtually through the multimedia portal of the German National Library of Science and Technology (TIB), hosted by Leibniz University in Hannover.
In this video, Prof. Dr. Klaus Lüders demonstrates conservation of angular momentum, assisted by Prof. Dr. Robert Otto Pohl. (Lüders, Klaus; Pohl, Robert Otto; Beuermann, Gustav; Samwer, Konrad: Drehstuhlexperimente zur Erhaltung des Drehimpulses. Physikalische Experimente nach Robert Wichard Pohl (1884 – 1976), IWF (Göttingen), 2003. https://doi.org/10.3203/IWF/C-14826.)