One hundred years ago Heike Kamerlingh Onnes arrived to one of the most important breakthroughs of 20th century physics - he discovered superconductivity. His finding as in many other cases in the history of science had been a result of use of a very new experimental technique. He used the cryogenic equipment in his Leiden's laboratory with the liquid helium cryocooler and measured electrical properties of metals near the absolute zero temperature. When cooled down to extremely low temperatures, near 4 Kelvin, very pure mercury suddenly lost its electrical resistance completely. Many major physicists of 20th century, experimentalists as well as theorists, devoted their life efforts to exploration of the mysterious properties of superconductors. Superconductivity has been shown to be one of the rare cases where quantum physics is observed on a macroscopic scale. Many chemical elements and thousands of compounds have been found to be superconducting. Fifty years after the discovery important practical applications such as strong magnets for laboratories and magnetic-resonance-imaging in hospitals came to the market. But more than seventy five years the superconducting materials had been functioning only at extreme cold, below 23 K (-250°C). In 1986 the "hightemperature superconductor's" era started with materials superconducting at -100°C. This paper surveys the history and the latest research into one of today's most fascinating physics and promising technologies., Peter Samuely., and Obsahuje bibliografii
Světelné znečistění odjakživa představuje palčivý problém zejména pro astronomy, kterým snižuje viditelnost noční oblohy. V posledních letech je však tomuto fenoménu věnováno mnohem více pozornosti i v jiných vědních oborech vzhledem k jeho negativním důsledkům, například v oblasti ochrany přírody, lidského zdraví, bezpečnosti či financí. V článku jsou tyto dopady stručně nastíněny a podrobněji jsou rozebrány fyzikální aspekty světelného znečištění, možnosti jeho měření a modelování a prognóza do budoucnosti., Light pollution (LP) poses a serious threat in particular, astronomers struggle with limited visibility of natural night sky objects. Due to the negative effects of bad lighting practices in various fields (e.g. environmental protection, human health, safety and security or economy) light pollution problematics have been extensively explored over the past years. This article presents a brief summary of these effects and a closer look into the physical aspects of light pollution, its measurement and quantification as well as future prospects., Milada Moudrá., and Obsahuje seznam literatury
Všude kolem nás je přítomno reliktní záření, světlo z období konce velkého třesku, které v sobě nese cenné informace o raném vesmíru a o prostředí, kterým k nám procházelo. Při poznávání vesmíru získáváme většinu informací o vzdálených objektech prostředníctvím elektromagnetického záření nejrůznějších vlnových délek. V mikrovlném oboru sledují dnešní specializované sondy nejen nejchladnější zákoutí vesmíru, ale i světlo dávných časů, které se vydalo na svou pouť v období, kdy se ve vesmíru formovaly první atomy., Cosmic microwave background radiation exists all around us. It is the light from the end of the Big Bang, which carries valuable information about the early universe and the environment, throught which it has passed. Most of the Information about distant objects we obtain through electromagnetic radiation at various wavelengths. In the microwave band today‘s specialised probes watch not only the coldest corners of the universe, but also the light from ancient times, which started its journey during the period when electron shells in atoms formed in the universe., Petr Kulhánek., and Obsahuje seznam literatury
Let us look at light used in art from the perspective of art history. Light is important in the methods used for displaying reality and the formation of different styles in painting. During the middle ages painters sought not only to display the real behaviour of light in the world but used light to view transcendental elements. Magister Theodoricus for example seemingly placed the light source inside the volume of figures of saints, and thus strengthened their spiritual presence in the area of the chapel in Karlštejn castle. The master of the Wittingau altar used a shadow to amplify the mystery of the scene, like the Dutch masters from the early 15th century in their night scenes. By using sfumato, Leonardo forced the viewer to start actively looking at indistinct contours of his characters and thus intensified their vividness. Caravaggio from before 1600 put emphasis on the contrasts of light and darkness, thus his chiaroscuro figures sharply emenate into light. The light carves objects out of the surrounding darkness and facilitates composing images. During this time, Galileo through his telescope and his art of drawing identified "spots" of the Moon as craters. Simultaneously, Annibale Carracci, and before him Jan van Eyck and after him Velásquez and many others used mirror optics for various pictorial representations of reality. Together, relations between light phenomena, optics and painting are rich in their complexity. and Ladislav Daniel.
This article discusses light propagation in an optical fibre from the point of view of both geometrical and wave optics. We describe the fibre eigenmodes and their wavefronts, evolution of a general state of light along the fibre, and the modes of a bent fibre. Numerous figures are used to illustrate the presented priciples., Tomáš Tyc., and Obsahuje seznam literatury
Zlaté sedmeré světlo, vůkol planoucí, duši ti dává směsice barev..., Light was the symbol of the Enlightenment or the Age of Light. The physics of light was widely studied and popularised at that time. The theoretical description of light inspired Maupertuis and Euler to formulate the Principle of the Least Action., Jiří Langer., and Obsahuje seznam literatury
Here we present some interesting aspects of interplay between quantum theory and functional analysis. We show that some of the deepest problems in both disciplines are unexpectedly equivalent. Starting from a historical point of view we comment on the following topics: connection between the structure of von Neumann algebras and the structure of quantum theories, construction of quantum integral and logic of quantum systems, Bell inequalities in light of Grothendieck inequality and operator space theory. Finally, we discuss bohrification and topos approach to quantum theory., Martin Bohata, Jan Hamhalter., and Obsahuje bibliografii
Vysychání kapek a následné formování "kávových kroužků" představuje velice zajímavou fyziku z běžného života. V článku se však pustíme dále - do oblasti aplikací tohoto jevu - a ukážeme si, jak pomáhá koncentrovat biomolekuly, které jsou pak přístupné studiu Ramanovou spektroskopií. Položíme si otázku, jak se liší konformace biomolekul v "kávových kroužcích" od jiných fází, přidáme však i přehled dosavadních užití až po biomedicínské aplikace., Desiccation of droplets and subsequent formation of "coffee rings" represents very interesting physics in an ordinary life. in this article, we go further into the region of applications of this phenomenon and we show that it helps to concentrate biomolecules, which are then accessible to Raman spectroscopy. We address questions about the difference of conformation of biomolecules in "coffee rings" with respect to other phases, finally we give an overview of the present employment of this method as far as biomedical applications., Vladimír Kopecký Jr., and Obsahuje bibliografii
Příspěvek nabízí jak nezbytné základní informace o tandemové výuce, tak osobní zkušenost autorky s realizací tandemové výuky fyziky na Gymnáziu Nový Jičín, která probíhala v prvním pololetí školního roku 2019/2020 u žáků 2. ročníku tohoto gymnázia. Cíle, které byly v rámci tandemové výuky fyziky sledovány, zahrnovaly prohloubení spolupráce učitele fyziky z gymnázia s odborníkem (v našem případě s vysokoškolským pedagogem z Katedry fyziky Přírodovědecké fakulty Ostravské univerzity), ověření, zda může tandemová výuka vést ke zlepšení kvality výuky fyziky, a ověření, zda může mít tandemová výuka pozitivní vliv na postoje žáků k fyzice. Po každé vyučovací hodině proběhla mezi vyučujícími reflexe s důrazem na zhodnocení použitých edukačních forem a metod a jejich vlivu na poznávací procesy žáků. Zjištění směřující k ověření stanovených cílů byla získána analýzou odpovědí z evaluačních dotazníků, jež vyplnili všichni žáci, kteří tandemovou výuku absolvovali. Průběžně byly s žáky vedeny také rozhovory. Součástí příspěvku jsou výsledky evaluace, upozornění na výhody i případná úskalí tandemové výuky fyziky, stejně jako osobní pohled a zkušenost autorky., The paper deals with tandem education and the author's personal experience with tandem physics teaching at Nový Jičín Grammar School ( first term of the 2019/2020, second class). The aims of tandem physics teaching include improving cooperation of a teacher with an expert (in this case it was a university lecturer, from the Department of Physics, the Faculty of Science, University of Ostrava). Verification of whether tandem education leads to improvement in physics education and has a positive impact on students' attitude to physics was also carried out. After each lesson, there was reflection among the teachers with an emphasis on the utilised educational forms and method and their influence on the cognitive processes of students. Verification of the goals were obtained by analysing answers in evaluation questionnaires, which were completed by all students who had finished the tandem education. Interviews were also conducted with students on an ongoing basis. This part of the paper includes the results of the evaluation, advantages and potential difficulties of tandem physics teaching, as well as the author's personal view and experience., Jana Škrabánková., and Obsahuje bibliografické odkazy