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NEWSLETTER – July 19th 2012 www.ipho2012.ee/newsletter

A jump into medieval life

Y

esterday all the competitors had a lovely chance to explore Estonia more during the excursion to Rakvere castle and to imagine how people lived in the old days when the laws of physics weren´t even written down. Right after entering the gates the medieval life unfurled in front of us as though we´d travelled back in time. Within only a few seconds the front yard of the castle had filled up with physicists trying out the mechanical carousel, exploring the medieval castle or climbing up the towers. It was as if the young scientists, who seem serious 24/7, had suddenly lit up. After the opening ceremony, which was accompanied by the real firing of a 500-yearold cannon, the students joined different workshops where they had the opportunity

to fashion things out of steel and clay under the eyes of the professionals, or learn how to make a candle in just a few minutes. While the boys put their warrior skills to the test, the girls had a go at horseriding. The most popular place probably was the old torture chamber in the cellar of the castle, where a humorous guide explained how people used to entertain themselves centuries ago. The day consisted of many historical contests, and this was when IPhO had its first champions. Battsooj from Mongolia, who had never held a bow in his hands, became IPhO’s archery champion. The highlight of the day was the ”fight against the flying cabbage competition“. The goal was to cut a cabbage into two halves with a sword while wearing a real warrior’s helmet. In the end it was Moldova against Australia. The lucky winner Siobhan, the

Photo: Siim Pille

Issue nO.5

only girl in the Australian delegation, commented laughing: ”Hopefully I can match this win with a gold medal in physics.“ But there was more. Only moments after the circus and the performance of the professional acrobats had ended, the front yard filled up with students trying to copy the acrobats they´d just seen. Everyone was surprised when 17-year-old Kaisar Bek from Kazakhs­ tan went on the stage and imitated the acrobats amazingly well. When asked about his skills he confessed he had often done some tricks for himself at school during the breaks. ”Anybody could do that!“ he said cheerfully. As the day passed the students made more new friends and, hopefully, calmed their nerves before the big challenge of the experimental exam waiting for them. Text: Anete Sammler


Picture gallery

Photo: Siim Pille

Photo: Andres Mihkelson

Cabbage fighting contest

Watch out!

Photo: Merily Salura

Photo: Merily Salura

Photo: Siim Pille

Surprise performer from Kazakhstan

Photo: Andres Mihkelson

On the edge of the Earth

Run for your life!

To the battle!

Preparing for the experimental examination

T

he curse of the long night struck again! Yesterday the leaders translated the experimental problems. They were examining the experiments with great interest. A leader from Japan said that they will take three copies of one experi­ment back to Japan: “We will use them to teach our students.“ The head of delegations hoped to finish the translations earlier than last time. “We are quite optimistic,“ said two leaders from Estonia. Text: Minna-Triin Kohv Photo: Karl Veskus


Physics in Estonia Jaak Kikas Head of Academical Committee

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stonia is one of the smallest European countries. Even so, physical research and education have their firm roots in the Estonian soil too. The story started in 1632, when the Swedish king Gustav II Adolf established in Tartu the Academia Gustaviana University. Already during this Swedish period Newtonian theories, quite new and not then generally accepted, were taught at the university. In 1802, now in the Russian Empire, the university’s first rector the physicist Friedrich Parrot was appointed (you can still see some nice physics demo setups he collected). Eminent scientists (to name a few) who contributed to the fame of the University are Lenz (sure you know the

Estonian astrono­ mers led to one of the greatest physical mysteries of our time.

Lenz’ Law), von Struve (astronomer, famous also for his meridian measurements – 2820 km from Norway to the Black sea), von Baer (more famous in biology, but Baer’s Law was referred to by Einstein), Ostwald (got the Nobel Prize for chemical kinetics – we like chemists too, do we?), Tammann (how many different phases of ice do you know - Tammann counted three already) and others.

Astronomy and astrophysical research have had a long tradition in Estonia, dating back to Struve. The milestones on this “road to the stars“ comprise determination of the distances to one of the brightest stars, Vega (Struve, 1837), to Andromeda galaxy (Öpik, 1922) and, finally, revealing the ultimate large-scale (“honeycomb“) structure of our Universe (Einasto, 1977). The modern studies by Estonian astronomers led to one of the greatest physical mysteries of our time – the missing mass in the Universe (search for “mass AND Einasto“). But space is not only for telescopes – space technology embraces a wider field of investigation. As to the Estonian students’ space project - find out, what EstCUBE is! Physics research in Estonia took a new direction in the 1950s. Studies of luminescence and luminophores soon expanded into a broader field of experimental and theoretical research into various optical phenomena in solids. Discoveries of the phenomena of hot luminescence (faster rather than really hot) and persistent spectral hole burning (a delicate way to manipulate the spectra of solids) highlighted these studies. There followed a demonstration of space-and-time domain holography (yes, you can do this if you manage to record the spectrum of light) and “fasterthan-light“ light pulses (no harm done to special relativity). Inspired by its unparalleled power in the research of structure and micro-properties of strategic materials like Estonia’s main energy source oil-shale (often referred to as “brown gold”) nuclear magnetic resonance (NMR) was introduced in Tallinn. This opened up possibilities for intensive studies of modern chemical compounds, catalysts, and novel superconductors. Now, you know this technique better as MRI (just magnetic resonance imaging without nuclear) and its traditions continue in the emerging Estonian MagnetLab. A non-exhaustive list of topics that physicists in Estonia are dealing with nowadays

Happy Birthday! Milan Krstajić

Saba Kharabadze

includes: optical phenomena (synthesis and properties of exotic light pulses, nanooptics & plasmonics); theory of dynamical phenomena in solids (non-linear vibrations,

By its very essence physics has no nationali­ ty and is increasingly carried out in interna­ tional collaborations.

phase transitions, novel superconductivity); synthesis and characterisation of nanomaterials (atomic layer depositions, scanning probe microscopy, graphene studies); magnetic phenomena in solids, including nano- and quantum magnetism, batteries and fuel cells, high-energy physics, astrophysics, etc. The main Estonian research institutions in physics are the Institute of Physics of the University of Tartu and the National Institute of Chemical Physics and Biophysics in Tallinn. However, exciting physical and physics-related research is also going on in different labs of the Tallinn Technology University and other institutions. By its very essence physics has no nationality and is increasingly carried out in international collaborations, extending to all continents (yes, even to Antarctica – find out what the Ice Cube is!). These collaborations enable physicists from small countries like Estonia to participate in frontline studies, for example at CERN (with LHC now running), large observatories, neutron sources and high magnetic field facilities in Europe, US and Japan. Estonian physicist are frequent visitors to synchrotron sources in Lund (Sweden) and Hamburg and are looking eagerly to the opening of the new European Spallation Source and European synchrotron facility Max-IV in Lund with an Estonian beamline. Stay tuned to physics news from Estonia!

Yummy chocolate fabric experi­ ence, leaders’ thoughts about the experimental examination and Rakvere castle pictures... As you know a picture is worth a thousand words AND there’s a lot of them - check it out from www.ipho2012.ee/newsletter


Delegates

Feynman’s Corner

Roads (solution) This a surprising example of a situation known in physics as “the broken symmetry”, where the symmetry of the solution is lower than the symmetry of the problem. Of course, there is an equivalent solution rotated by 90°.

Dew on grass (solution) It turns out that small water droplets work as retro-reflectors. A retro-reflector reflects incident light directly back towards its source. Consider a parallel beam falling on to a sphere of refractive index n = 2; those rays which enter the sphere with a small impact parameter are reflected directly back. Indeed, the spherical surface of the ball works as a thin lens and focuses the rays into a single point at the opposite surface of the sphere. The ball’s surface reflects the light partially back, and the aforementioned “lens” reverts the conical light rays into a back-propagating parallel beam. Note that such small spheres are used for the production of one type of retro-reflective materials (for safety clothing, road markings etc); the other type of retro-reflective material is referred to as a corner reflector, see also http://en.wikipedia.org/wiki/Retroreflector. A water droplet with a too small refractive index is not a perfect retroreflector, but still, some light rays which enter the droplet at a correct distance from its centre are reflected back.

The total length of the above construction for the unit square is 31/2+1 » 2.73, compared to the value of 2×21/2 » 2.83 for the crossed diagonals, e.g. Essentially the same problem arises when considering the minimum surface of the soap film spanning four parallel long rods. Sandcastle Sandcastles cannot be built with dry sand. Meanwhile, too wet is also not good: when flooded, a sandcastle will fall down. Why?

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