Day 1: Physics makes everything awesome!

I am sitting in Auckland Airport, waiting to board my flight to Europe via LA. Looking past my reflection in the window and out onto the tarmac, I can see one of the enormous jets of the 777 that is about to carry me over the Pacific. The compressor is spinning slowly, the little spiral in the centre rotating. By the landing gear of the plane stands an official with his hands folded behind his back. I wonder what he's thinking?

For me, just a moment's reflection on the physics underlying the journey on which I am about  to embark is dizzying - both in terms of the technology that will take me to the other side of the world, and the nature I will travel through to get there.

Looking at the world and trying to make sense of its underlying physics makes everything awesome.

I am a high school physics teacher. I have won a scholarship to travel from New Zealand to Switzerland and Germany to visit some of the most awe-inspiring science and technology sites from Geneva to Berlin. As I make my way through a packed itinerary, I will use this blog to sustain my curiosity about the physical world and ask questions along the way that I may share with my students on my return. This blog is for asking questions about physics.

As I wait to board my plane, all around me people are sitting, running their fingers over their tablet screens, fanning the stuffy air past their bored faces with their boarding passes. A child is climbing under the metal frames of the seats.

As Louis CK says, everything's amazing and nobody's happy.

Day 2: While watching the wing of an aeroplane

How do these movable sections affect the lift force?

As we flew across the Pacific, I spent a lot of time looking out across the wing at the cloudscape below. Dozens of questions came to mind about the formation of clouds, their shape, why they form in layers, etc., but what made me slightly nervous was the amount of upward force that must be exerted on the wings to allow us to remain in equilibrium up there. Apparently the mass of a fully loaded 777 is about 300,000 kg.

So the physics question for this day/night(?) is: The lift force on this 300,000 kg plane must be about 3,000,000 N. What are the factors that affect his lift force?

Day 3: The Bells of Saint-Pierre, Vieille Ville, Geneva

The Clemence Bell, Cathedral Saint-Pierre

During my walk around the old town of Geneva, I visited the archaeological site underneath the cathedral of Saint-Pierre. I saw the place where the great bell "Clemence" was moulded 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 of the bell you are casting, what pitch the bell will produce when struck?

Day 4: Where particles are smashed together, CERN, Geneva

Tinkering with magnetic quadrupole

I visited CERN today, and unfortunately, the tour was closed due to their being in the midst of their 60th birthday celebrations. However, their Microcosm exhibition was amazing. 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 the tiny early one, only a few centimetres in diameter, to the 27 km LHC. 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, but today's physics question relates to how the exotic particles that are being studied are produced.

The physics question for today is: When two particles collide at high velocity, why does their energy convert to new matter (and not electromagnetic photons - like in an x-ray tube)? Does our current model allow us to predict what matter will be produced in a particular collision? If so, HOW?

Day 5: The world's first battery, Musee d'histoire des sciences, Geneva

At the History of Science Museum on the shore of Lake Geneva, I was engrossed in the impressive collection of scientific apparatus and notes on the lives of the scientists who designed and used them. In one of the rooms, I stumbled on an account of one of the great blunders 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, 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, 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 when the magnet passes in front of the wire. He would have observed this had he left the galvanometer in sight. Induction was eventually discovered by Michael Faraday in 1831.
Moving through the densely packed collection, in an unassuming glass case, I discovered one of the greatest inventions of all time... one of the original prototypes of Volta's first battery.

The physics question for today involves a bit of chemistry: How is this electric pile pictured above able to produce a voltage to push a continuous electric current around a circuit (the pile is made of alternate copper and zinc discs, separated by cardboard soaked in salt water)?

Day 6: Plasma physics at the CRPP, Lausanne

Today I visited the CRPP - the plasma research centre on the campus of the Federal Polytechnic of Lausanne. Yves, our guide, is a physicist involved in managing the projects involving their experimental nuclear fusion reactor. He took me and a group of Swiss high school students through the facility, explaining the basic "basic" physics. This is an awesome combination of almost all aspects of physics in one machine. Microwaves at the different resonant frequencies of electrons and ions are used to raise the temperature of the plasma, enormous magnetic fields are used to trap the plasma in a helical trajectory around the torus, the Doppler shifting of laser light is used to determine the temperature, the angular momentum of the particles in the plasma has to be corrected for... It is an impressive compilation of all branches of physics. 

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?

Day 7: Time travel on a train between Lausanne and Bern

After saying my farewells to Bern, the town where Einstein first conceived his special theory of relativity, I boarded my train bound for Zurich. Speeding through the countryside, I found myself reflecting on the relationship between time and speed and space.

The physics question for today is: in a train travelling directly eastward will your day be extended or shortened, and how does the lengthening/shortening depend on the speed of the train?

Day 8: Muons at the start of he Einstein museum, Bern

In 1905, while living in Bern and working as a patent clerk, Albert Einstein published a number of seminal papers that changed the way we understand time, space, and the fabric of "stuff" on the smallest scale were, to an extent, redefined as a result of his papers on Special Relativity and the Photoelectric Effect. The impressive Einstein exhibition at the Historical Museum laid bare a fascinating, complicated life alongside brief explanations of his remarkably simple, groundbreaking theories.

At the beginning of the exhibit, there was a scintillator showing the regular arrival of muons travelling at near the speed of light from the upper atmosphere. These short-lived particles ought not to make it to this low altitude.

The physics question for today is: 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?

Day 9: At the Zurich Hauptbahnhof

While drinking my coffee, waiting on platform 13 of the imposing Zurich Hauptbahnhof for the train that would carry me to Munich, I noticed that the electric locomotives were powered by a single point of contact with an overhead wire above the train.

The physics question for today is: How is it possible to power an electric motor with only this single electrical contact?

Day 10: Backwards Clock of the Isartor

Isartor's Backwards Clock

Since my visit to the Einstein Museum in Bern, the concept of time has been turning around in my head. While trying to find my way to the Deutsches Museum, I came across a clock that looked at first as if it were showing the wrong time. On closer inspection, I noticed that all of the numbers on the face of the clock were reversed. The clock was a mirror reflection of a real clock, its hands turned the other way; behind its face, all of the clockwork must have been meticulously designed to run in reverse. On the opposite side of the tower was an identical clock running "forwards" - i.e. the correct way.

I recalled seeing, in the Musee d'Histoire des Sciences in Geneva, an orrery. This machine, a clockwork model of the solar system, can be seen as a sort of metaphor for what is now termed "classical" mechanics - i.e. physics prior to relativity and quantum physics. The universe is governed by clearly identifiable and deterministic laws; it evolves in a perfectly predictable way as if it was driven by a sort of clockwork mechanism. This is an attractive prospect - it makes it seem as though the universe is really knowable, on the most fundamental level, through physics.

Seeing this clock on the Isartor turning backwards throws up some interesting philosophical questions. What if time really did run backwards? What if the mechanism behind the "clockwork universe" was reversed? How would our world look different?

The physics question for today: Imagine a world where time runs backwards. The world would look like a film played in reverse. What physics experiment could you do to determine that time was, indeed, running in reverse and not "forwards"?

Day 14: Neutron Reactor at HZB

Bioref Reflectometer - neutrons pass through "guide" pipe on the right

The neutron research reactor at the Helmholtz Zentrum Berlin was my destination this morning. I arrived at Wannsee, and took the bus to Hahn-Meitner Platz (recognise those names?). I was about a half-hour early, so I decided to take a walk through the surrounding forest. The facility was surrounded by an overgrown forest and double barbed wire fences with security cameras every twenty metres or so.

After I had given my passport details at the security gate, my host, Robert Wimpory, came and welcomed me to the facility. We put on our electronic radiation badges, recorded the starting radiation level in a little book, and headed past another security gate into the reactor area. At the centre of the facility there were stacks of concrete blocks, and behind them, I was told, was the reactor itself - a uranium fission reactor. It emits neutrons radially outwards in all directions, and "guides" lead out to an array of diverse, ingenious experiments (see setup here):

Some experiments were geared towards determining the fundamental properties of matter, some were investigating the structure and behaviour of molecules involved in biochemistry, some were investigating the paints used in artwork masterpieces, while others were testing the structural properties of materials for engineering purposes. In some places diffraction of neutrons through materials was exploited, in others, their magnetic properties were used. One enormous new piece of equipment, the High Field Magnet (HFM), being installed was capable of producing magnetic fields up to 25T (this, Robert informed me, was why the ceiling was so high) to deflect the neutrons. Here is an animation explaining the operation of the HFM.

How cool would it be to be working on one of these experiments, shoulder to shoulder with teams engrossed in their own investigation, 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.

The physics question for today is: If a neutron carries no overall charge, how is it that it can interact with a magnetic field?

Source for image (labelled for reuse with modification): 

Day 14: Radiation on a Plane

When I was replacing my dosimetry badge after leaving the HZB nuclear reactor in Wannsee, I asked Robert if he had ever had to take time off due to exposure to radiation. His replied that pilots, and even frequent flyers, are exposed to significantly larger doses than those working in this reactor. In fact, he said, pilots have a younger retiring age than most professions for this very reason.

I am now sitting in the back of a 747 somewhere over China, trying to keep from elbowing my neighbours as I type. Engrossed in a film - some science fiction epic - the lady beside me is unaware that she is being bombarded with unusually high levels of radiation.

The physics questions for today are: Why are we exposed to more radiation when we are flying than when we are on the ground? What is the nature of this radiation? And what is the source?