The hitchhiker’s guide to physics
26/11/2014Join physics teacher FELIX OLSSON as he explores European scientific landmarks, in a quest to plan the perfect class trip.
Introduction
As a New Zealand high school physics teacher, like many of my peers locally and internationally, I am always looking for ways to better understand my subject and to better understand how students learn – and what gets them excited about physics. I’m lucky to be working in a country that has an incredibly open and exciting curriculum, and I am privileged to be at a school that encourages its teachers to develop their practice through experimentation with the possibilities offered by new ideas in teaching and learning.
I was blown away when my school approved my application for a scholarship to travel to Europe over the October holidays to further my professional development. They offered me this scholarship to travel from Geneva to Berlin over two weeks with the objectives of a) visiting some of the most awe-inspiring science and technology sites in Switzerland and Germany open to the public; b) planning and developing an itinerary for a physics-focused trip through Switzerland and Germany suitable for inspiring a group of high school physics students; and c) to meet with educators overseas to share ideas about pedagogy and new developments in the use of ICT in the physics classroom.
I want to give special thanks to Tristan O’Hanlon, who, prior to my trip, passed on a wealth of knowledge and experience from his two trips through Europe with students, and whose itinerary I used as a starting point for planning my journey.
Before departing New Zealand, I took a look at my packed itinerary and decided to set up a blog to record some reflections on the physics I came across in my travels. To focus my attention, and as a reminder to maintain my curiosity, I set myself the task of each day coming up with a physics question relating to the places I visited. As I did this, I was very quickly reminded of the fact that physics is everywhere, and that maintaining our awareness of this makes nature and technology even more awesome.
What follows is an edited version of my blog reflections from some of the highlights of the trip.
Vieille Ville, Rousseau and the Bell of Saint-Pierre, GENEVA
Left: The Bell of Saint-Pierre. Image: Wikimedia Commons.
A 16,000 kilometre trip across twelve time zones is about as large a journey in space and time as one can take and still remain on the planet. To adjust my body and mind to my new location, I decided to begin my time in Geneva by stretching my legs and taking a walk through the historical Old Town.
It was a quiet Sunday morning, and access to the ancient Cathédrale Saint-Pierre was temporarily barred due to the Sunday service. I had hoped to climb the North Tower, to get a better view of my new surroundings, but had to put those plans off. Instead I strolled a few blocks through the quiet, cobbled streets of the Old Town to the Espace Rousseau. The museum was established at the birthplace of the great Genevan thinker, Jean-Jacques Rousseau, to disseminate some of his ideas in the form of a fascinating A/V installation. Prior to my visit, I had not been aware of Rousseau’s contribution to pedagogy and education, expressed in his novel Emile, or On Education (1762), which inspired the new curriculum in France after the revolution. “The abuse of books,” wrote Rousseau in Emile, “kills science. Believing that we know what we have read, we believe that we can dispense with learning it.” The argument against pedagogies drawing too heavily on passive book learning might have started two and a half centuries ago with Rousseau – it remains a hot topic of discussion amongst teachers on Twitter feeds today.
I returned to the cathedral, and heard the organ music still filtering through the heavy doors into the square. Realising that the service was still in progress, I made my way to the entrance to the archaeological site underneath the building. Amongst the excavations, I saw the place where the cathedral’s great bell "Clemence" was cast in 1407.
As I later climbed the North Tower of the cathedral, I heard the bell chime tunefully, along with a number of smaller bells.
The physics question for today is: How can you predict, based on the dimensions and material of the bell you are casting, what pitch the bell will produce when struck?
CERN and Huge Scale International Collaboration, GENEVA
Left: Particle Accelerator, CERN, Geneva. Photo: Felix Olsson.
I visited CERN today, and unfortunately, the guided tour was closed due to their being in the midst of their 60th(!) birthday celebrations. However, I was able to make my way through their amazing Microcosm exhibition. It included a number of recordings of physicists talking about what they thought were the biggest, most fascinating unsolved mysteries of the universe. It also showed the evolution of particle accelerators, from an early prototype, only a few centimetres in diameter, to the massive, 27 km diameter Large Hadron Collider. I have understood (more or less) how the accelerator works - though I get a kind of vertigo when I think of the magnitude of the undertaking of building this.
Perhaps more impressive than any of the science I saw at CERN was the inspiring level of sustained, massive-scale international collaboration, without which the multitude of ground-breaking projects carried out at the site would never have been able to get off the ground. In a world that seems on many levels to be focused on the differences and disputes between nations and people, it is inspiring to see physics bring people together in genuine collaboration.
Today's physics questions relates to how the exotic particles that are being studied are produced.
The physics question for today is: When two massive particles collide at (VERY) high velocity, why does their energy convert to new matter? Does our current model allow us to predict what matter will be produced in a particular collision? If so, HOW?
The Musee d’Histoire des Sciences, GENEVA
A short bike ride through the park that lines the shore of Lake Geneva, on a hill overlooking the lake, is the History of Science Museum. The impressive collection of scientific apparatus and the stories behind them and the scientists who designed and used them (the museum takes great care in the presentation of these stories), really give a sense of how the history of science is littered with failed attempts, flawed experiments, violent clashes of personalities, and accidental discoveries. The fact that the progress of science is a messy business is often concealed in the way we teach and learn physics.
Right: Musee d'Histoire des Sciences, Geneva. Photo: Felix Olsson.
In one of the rooms, I stumbled on an account of what must be one of the greatest near-discoveries in the history of electromagnetism. We've all heard of Michael Faraday, but how many of us are familiar with Genevan scientist Jean-Daniel Colladon?
In 1825, the young Colladon was seeking to prove that a magnet presented to a coil of conducting wire can induce an electric current in the wire. In order to ensure that the magnet did not interfere with the galvanometer, however, he placed the latter in a different room. After presenting the magnet to the wire coil, he moved to the other room to observe the galvanometer, and saw that the needle had not moved. The young scientist had not realised that induction is transitory, and occurs only while the magnet moves in the vicinity of the coil. He would have observed this had he left the galvanometer in sight.
Electromagnetic induction, the process by which we now generate almost all of the electricity we use, was discovered six years later, in 1831, by Michael Faraday.
Left: Volta's Electric Pile, Geneva. Photo: Felix Olsson.
Moving through the densely packed collection, in an unassuming glass case, I discovered one of Alessandro Volta’s original prototype batteries, the electric pile, designed in 1800. It is made of a stack of alternate copper and zinc discs, separated by cardboard soaked in salt water.
The physics question for today: How is Volta’s electric pile able to produce a voltage to push a continuous electric current around a circuit?
CRPP, Plasma Physics, and Future Focused Problem Solving, LAUSANNE
On my way through Lausanne, I visited the CRPP - the plasma research centre on the campus of the Federal Polytechnic of Lausanne. Yves, our guide, is a physicist managing projects involving their experimental nuclear fusion research reactor. He also helps to co-ordinate their involvement in the massive international collaboration: ITER (Latin for “The Way”). This project, based in southern France, is aimed at finally making power generation through nuclear fusion a reality, a goal that is expected to be realised by the year 2050. Listening to Yves speak with excitement about this, it occurred to me that projects like these require that we assume a broader perspective on time, progress and education than that to which we are accustomed. Many of the scientists that will be completing the projects that are just now beginning have not yet been born!
I joined up with a group of aspiring young physics students who had travelled from a high school in Zurich, as Yves brought us through a passage in the enormous concrete shielding wall to their research reactor.
From Yves’ explanations of the “basic” physics and the questions of the students and teachers in the group, we quickly came to realise that this project was an awesome combined application of almost all aspects of physics in one machine. A plasma made from deuterium atoms is injected into the torus and confined to move in a helical path through a strong (!) circular magnetic field. Microwaves at the different resonant frequencies of electrons and ions are used to heat the plasma to temperatures in the order of a hundred million degrees. Doppler shifting of laser light reflected off the plasma is used to monitor its temperature. Although this reactor will never be used to produce energy, the idea is to exploit the energy of neutrons emitted in the fusion of deuterium and tritium to provide heat for energy generation.
The physics question for today is: In order to keep the plasma contained inside the reactor, a strong magnetic field is used. How does this work, and what shape must the magnetic field be to produce the helical trajectory followed by the plasma around the torus?
Einsteinmuseum, BERN
Above: At the Einsteinmuseum, Bern. Photo: Felix Olsson.
In 1905, while living in Bern and working as a patent clerk, Albert Einstein published a number of seminal papers. His papers on Special Relativity and the Photoelectric Effect changed the way we think not only about space, time and the nature of “stuff” on the very small scale, but also how we think about the nature of scientific discovery and creativity.
I crossed the Aare River, and climbed the hill towards the imposing façade of the Historical Museum which houses the Einstein exhibition. It is enormous, and lays bare a fascinating, complicated life alongside brief explanations of his ingenious and remarkably simple, ground-breaking theories.
I discovered, amongst the biographical details of his life, that the widely held belief that Einstein hated school and was bad at it, is a myth. In fact, Einstein loved his last years of high school, was the youngest in his graduating year, and achieved higher average grades than any of his fellow graduates. The key to his discovery of the joy of learning and education was the progressive pedagogy adopted by the school he attended in Aargau, Switzerland. In his own words, “It made me clearly realise how much superior an education based on free action and personal responsibility is to one relying on outward authority.” The school had embraced the student-centred approach endorsed by Swiss pedagogue Pestalozzi (who had been profoundly influenced by Rousseau’s earlier ideas on education).
At the beginning of the exhibit, there was a scintillator showing as little flashes the regular arrival of muons travelling at near the speed of light from the upper atmosphere. These short-lived particles provided ought not to be able to make it to this low altitude.
The physics question for today is one relating to one of the first experimental confirmations of the predictions made by Einstein’s Special Theory: How is it that muons from the upper atmosphere, whose short average lifetime should result in their decay long before reaching the Historical Museum, are being detected with remarkable regularity in the scintillator at the beginning of the Einstein exhibition?
The Helmholtz Zentrum and its Neutron Reactor, BERLIN
Above: Neutron Guide, Helmholtz Zentrum, Berlin. Photo: Helmholtz-Zentrum Berlin.
After about a half hour train ride from central Berlin, is the Helmholtz Zentrum’s Wannsee site. Upon arrival, I found myself standing at a deserted and silent Hahn-Meitner Platz (recognise those names?) between an overgrown forest and the barbed wire fence around the nuclear research facility I had arranged to visit today. The road was lined with plaques about the various projects underway at the facility, but even after reading these, I had about half an hour to pass before my tour. I decided to skirt the security fence, and take a walk through the surrounding forest. The facility was encircled by two razor wire fences, separated by a cordon about twenty metres wide. At one stage, looking past the security cameras through the two fences, I spotted what must have been a group of scientists having a game of volleyball.
After I had given my passport details at the security gate, Robert, my contact at the facility, came and welcomed me. We put on our electronic radiation badges, recorded the starting radiation level in a little journal, and headed past another security gate into the reactor area. The reactor was housed at the centre of an enormous warehouse filled with machinery. At the centre of the facility there was an enormous pile of concrete blocks, stacked like Lego, and behind them, I was told, was a uranium fission reactor. The fission taking place in the uranium fuel rods emits an enormous amount of neutrons radially outwards in all directions. The purpose of this facility was to exploit the properties of these neutrons to probe materials in experiments set up around the warehouse. The neutrons are guided from the reactor to the experiments by a number of “guides,” or pipes, the insides of which are reflective to neutrons.
Perhaps the most striking thing about my tour of this facility was the diversity of the experiments being undertaken there. It housed experiments set up by biologists, engineers, physicists and art historians. Some were geared towards extending our understanding of the fundamental properties of matter and the laws of physics, others were investigating the structure and behaviour of molecules involved in biochemical processes, and still others were testing structural properties of materials to better understand how to strengthen them structurally. One fascinating experiment involved bombarding famous oil paintings with neutrons in a process called “neutron activation autoradiography.” The radiation subsequently emitted by the paintings allows experimenters to see the order in which the pigments were originally laid down, and even whether the canvas has earlier paintings concealed underneath the surface paint.
In some experiments, diffraction of neutrons through materials was exploited, in others, their magnetic properties were used. One enormous, newly installed piece of equipment, the High Field Magnet (HFM), is capable of producing magnetic fields up to 25 tesla (this, Robert informed me, was why the steel ceiling of the building had to be so high) to deflect the neutrons.
How cool would it be to be working on one of these experiments, shoulder to shoulder with teams engrossed in their own investigations, COMPLETELY different in nature? According to Robert, all you have to do is come up with an experiment and then apply for "beam time." Then, pending approval by a panel, your experiment can be scheduled.
Many of Robert’s descriptions of the experiments in the facility threw up interesting questions. The physics question for today is: If a neutron carries no overall charge, how is it that it can interact with a magnetic field?
Final Thoughts
I can’t wait to bring a group of students through Switzerland and Germany in April, 2015. Seeing the culmination of these enormous, ground-breaking collaborative projects in science, that are alive with young scientists doing meaningful research is inspiring, whether you are a student or a teacher. I cannot imagine a better way to encourage aspiring students to make a contribution to the exciting field of physics. This will be the ultimate field trip.
I encourage anybody interested in pursuing a similar trip to get in touch. I am happy to share my contacts and details of planning the logistics of the trip.
- Felix Olsson is a science teacher at St. Cuthberts School in Auckland.
felix.olsson@stcuthberts.school.nz
The blog can be accessed here: http://transeuropephysicsexpress.blogspot.co.nz/
