Demonstration experiments in physics teaching: Bernoulli equation

Kvaliteta nastave fizike u školama od ključne je važnosti jer ona ne samo da treba dati temelje u razumijevanju osnovnih prirodnih pojava ključne za sve prirodne znanosti, već treba kroz fizikalni način razmišljanja učeniku dati alate i vještine koje može primijeniti u svakom segmentu života. Nastavnici i stručnjaci u svijetu neprestano rade na razvoju tehnika i metoda učenja fizike. Cilj novog nacionalnog kurikuluma trebao bi biti prijenos najboljih svjetskih iskustava u sve školske predmete. Tradicionalni oblici nastave, koji su učenicima često teški i nerazumljivi, mijenjaju se (često i do 50% kao u skandinavskim zemljama) s različitim oblicima projektne ili terenske nastave bazirane na istraživanju i individualnom pristupu. Osnovni alat za promjenu tih koncepata u nastavi fizike je pokus. Fizika je prirodna znanost temeljena na pokusu. Pokus u nastavi fizike kod djece potiče kreativnost, razvijaju kritičko razmišljanje i zaključivanje. Ovim radom u odabranoj temi Bernoullijeva jednadžba, želi se pokazati da se jednostavnim pokusima mogu na zanimljiv način prikazati bitna fizikalna svojstva. Ovi primjeri mogu biti sastavni dio nekog budućeg kataloga fizikalnih pokusa koji bi uz odgovarajuću edukaciju i motiviranje nastavnika bio okosnica moderne nastave fizike.The quality of teaching physics in schools is crucial because it contributes not only to the understanding the basic natural phenomena that are important for all the natural sciences, but also gives student through a physical way of thinking the tools and skills that can be applied in every aspect of life. Teachers and experts in the world are constantly working to develop techniques and methods of teaching physics. The aim of the new Croatian national curriculum should be a transfer of the world's best experiences in all school subjects. Traditional forms of teaching, that are often heavy and obscure to sudents, are replaced (often up to 50% as in the Scandinavian countries) with various forms of project based learning that is based on research and individual approach. The main tool to change these concepts in physics is experiment. Physics is a natural science based on experiments. The experiment in physics teaching encourages creativity, develop critical thinking and reasoning. This work in the chosen topic of Bernoulli equation will show that simple experiments can be an interesting way to display important physical concepts. These examples may be part of a future catalog of physical experiments that can become with proper training and motivation of teachers, the backbone of modern physics teaching

Prospective chemistry teachers' perceptions of their profession : the state of the art in Slovenia and Finland

The main purpose of this paper is to present Slovenian and Finnish prospective chemistry teachers' perceptions of their future profession, especially with regard to their understanding of the role of the triple nature of chemical concepts (macro, submicro and symbolic) and their representations in chemistry learning. A total of 19 prospective teachers (10 Slovenian, 9 Finnish) at master's level in chemical education participated in the research. The prospective teachers' opinions were gathered using an electronic questionnaire comprising six open-ended questions. The study revealed many parallels between Slovenian and Finnish prospective chemistry teachers' perceptions of their future profession and their understanding of the role of the triple nature of chemical concepts, especially particle representations, in chemistry learning. The majority of the prospective teachers from both countries believe that personal characteristics are the most important attribute of a successful chemistry teacher. Thus, they highly value teachers' enthusiasm for teaching and the use of contemporary teaching approaches in chemistry. The prospective teachers displayed an adequate understanding of the role of the triple nature of chemical concepts (i.e., particle representations) in the planning and implementation of a specific chemistry lesson.Peer reviewe

Paleopoplave v porečju kraške Ljubljanice

The scientific monograph ('Palaeofloods in karstic Ljubljanica River Catchment') presents a research on palaeofloods in the main water confluence in the Ljubljanica River Catchment, namely the area between the Pivka Basin, Cerknica Karst Polje, and Planina Karst Polje. Several geomorphological forms genetically related to floods have been identified, e.g. floodplains, river terraces, corrosion notches on cave walls, as well as laminated fine-grained sediments. Since they were found at higher altitudes than the present floods reach, they were considered as palaeoflood features. Morphometric analysis of the studied geomorphological forms was used to determine the volume of palaeofloods and their altitudinal range. The hydrometric characteristics of the palaeofloods where calculated by computer modelling. Petrological analyses of fine-grained sediments from the surface and caves were used to determine the origin of sediments and their settling velocities, hence to prove their flood origin. Furthermore, morpho-chronological analyses with radiometric methods 14C and U-Th on flowstones interlaying with flood sediments where carried out. The results show that the volume and altitude of palaeofloods throughout the study area fairly exceeded the highest known recent floods. In the Pivka Basin three palaeoflood periods were determined showing a decline of palaeofloods' altitude through time. Although palaeofloods reached higher altitudes, the dynamics of palaeofloods was similar to the dynamics of recent floods: laminated fine-grained sediments were deposited from suspension during palaeofloods, which is also characteristic of recent floods in the Pivka Basin and of other karst poljes of the Notranjska Region. Laminated material confirms periodical flooding, while its depth and thickness prove the durability of the processes, contradicting older theories which assumed the karst poljes where permanently flooded in the past geomorphological periods. In conclusion it was established the Ljubljanica River Catchment developed in several stages, with changing dynamics of the geomorphic processes reflecting palaeoenvironmental change in the Quaternary.Paleopoplave v porečju kraške Ljubljanice so bile preučevane na območju najpomembnejšega sotočja vod, med Pivško kotlino ter Cerkniškim in Planinskim kraškim poljem. Poplavne oblike se na tem območju pojavljajo tudi na bistveno višjih nadmorskih višinah kot jih dosežejo najvišje poplave v današnjih hidroloških razmerah. Te oblike, ki so danes nad hidrološko aktivnim nivojem, so obravnavane kot sledi paleopoplav. Z več metodami je bil ugotovljen prostorski obseg ter dinamika sedimentacije gradiva ob paleopoplavah. Časovna umestitev paleopoplav je temeljila na datacijah sige z radiometričnima metodama 14C in U-Th. Ugotovljeno je bilo, da je bila jakost poplav v preteklosti bistveno večja, a je bila dinamika pojavljanja paleopoplav podobna današnjim. Tako kot ob današnjih poplavah v porečju Ljubljanice se je tudi ob paleopoplavah iz suspenzije odlagalo drobnozrnato gradivo. Hidrološki razvoj porečja se je skladno z dinamiko geomorfnih procesov spreminjal skozi več faz paleookoljskih sprememb v kvartarju. &nbsp

Paleopoplave v porečju kraške Ljubljanice

The scientific monograph ('Palaeofloods in karstic Ljubljanica River Catchment') presents a research on palaeofloods in the main water confluence in the Ljubljanica River Catchment, namely the area between the Pivka Basin, Cerknica Karst Polje, and Planina Karst Polje. Several geomorphological forms genetically related to floods have been identified, e.g. floodplains, river terraces, corrosion notches on cave walls, as well as laminated fine-grained sediments. Since they were found at higher altitudes than the present floods reach, they were considered as palaeoflood features. Morphometric analysis of the studied geomorphological forms was used to determine the volume of palaeofloods and their altitudinal range. The hydrometric characteristics of the palaeofloods where calculated by computer modelling. Petrological analyses of fine-grained sediments from the surface and caves were used to determine the origin of sediments and their settling velocities, hence to prove their flood origin. Furthermore, morpho-chronological analyses with radiometric methods 14C and U-Th on flowstones interlaying with flood sediments where carried out. The results show that the volume and altitude of palaeofloods throughout the study area fairly exceeded the highest known recent floods. In the Pivka Basin three palaeoflood periods were determined showing a decline of palaeofloods' altitude through time. Although palaeofloods reached higher altitudes, the dynamics of palaeofloods was similar to the dynamics of recent floods: laminated fine-grained sediments were deposited from suspension during palaeofloods, which is also characteristic of recent floods in the Pivka Basin and of other karst poljes of the Notranjska Region. Laminated material confirms periodical flooding, while its depth and thickness prove the durability of the processes, contradicting older theories which assumed the karst poljes where permanently flooded in the past geomorphological periods. In conclusion it was established the Ljubljanica River Catchment developed in several stages, with changing dynamics of the geomorphic processes reflecting palaeoenvironmental change in the Quaternary.Paleopoplave v porečju kraške Ljubljanice so bile preučevane na območju najpomembnejšega sotočja vod, med Pivško kotlino ter Cerkniškim in Planinskim kraškim poljem. Poplavne oblike se na tem območju pojavljajo tudi na bistveno višjih nadmorskih višinah kot jih dosežejo najvišje poplave v današnjih hidroloških razmerah. Te oblike, ki so danes nad hidrološko aktivnim nivojem, so obravnavane kot sledi paleopoplav. Z več metodami je bil ugotovljen prostorski obseg ter dinamika sedimentacije gradiva ob paleopoplavah. Časovna umestitev paleopoplav je temeljila na datacijah sige z radiometričnima metodama 14C in U-Th. Ugotovljeno je bilo, da je bila jakost poplav v preteklosti bistveno večja, a je bila dinamika pojavljanja paleopoplav podobna današnjim. Tako kot ob današnjih poplavah v porečju Ljubljanice se je tudi ob paleopoplavah iz suspenzije odlagalo drobnozrnato gradivo. Hidrološki razvoj porečja se je skladno z dinamiko geomorfnih procesov spreminjal skozi več faz paleookoljskih sprememb v kvartarju. &nbsp

Morfogeneza in klasifikacija korozijskih uravnav v Sloveniji

A new study of corrosion plains in Slovenia provides a systematic classification based on their geological settings and morphology. They are grouped into four types: karst plains, dry poljes, marginal plains of contact karst, and marginal plains of fluviokarst. Karst plains are the largest, formed through denudation under stable tectonic and hydrogeological conditions. Dry poljes are closed basins composed of bedrock and scattered sediment. Marginal plains of contact karst are formed at the boundary between non-karst and karst environments, while marginal plains of fluviokarst result from multiphase formation of poljes due to tectonic activity. This study enhances understanding of corrosion plains and can assist in their identification and management in karst areas.Raziskava korozijskih uravnav v Sloveniji podaja sistematično klasifikacijo korozijskih uravnav na podlagi njihovih geoloških in morfoloških značilnosti. Klasifikacija jih združuje v štiri kategorije: kraški ravnik, suho kraško polje, robna uravnava kontaktnega krasa in robna uravnava fluviokrasa. Kraški ravniki so največji in nastanejo z denudacijo v stabilnih tektonskih in hidrogeoloških razmerah. Suha kraška polja so zaprte živoskalne kotanje le mestoma prekrite s sedimenti. Robne uravnave kontaktnega krasa so nastale na stiku kraških in nekraških kamnin. Robne uravnave fluviokrasa so nastale z večfaznim razvojem kraških polj zaradi tektonske dejavnosti. Ta raziskava prispeva k boljšemu razumevanju korozijskih uravnav in lahko pomaga pri njihovi identifikaciji in upravljanju v kraških območij

The role and importance of the landscape park Udin Boršt

Udin Boršt is an isolated conglomerate terrace in Gorenjska region, Slovenia. A number of surface karst features and caves developed here due to the predominance of carbonate gravel. It is one of the last contiguous areas of lowland forest in Gorenjska region, and a popular recreation location for the people living nearby. Due to its karst surface and the forest it offered shelter to the locals in turbulent times. Its role during the period when bandits (rokovnjači) was common and during the Second World War is still preserved in folk memory. Due to its natural and cultural heritage, the area was protected as a Memorial park in 1985, but the legislation has become outdated and needs to be amended and updated. This article presents new findings on the geomorphological and intangible cultural heritage that need to be incorporated in the amended legislation

Procjena karijes rizika u djece

Karijes je usko povezan s razvojem dentalne medicine kao znanosti i kliničke discipline od njenih začetaka. Budući da karijes ima biološku podlogu, samim time posjeduje osobinu nepredvidivosti, kao što je to uvijek slučaj kada promatramo određene pojave u živom mediju. Pristup karijesu u kliničkoj praksi temelji se na odgovarajućem dijagnostičkom sustavu koji uključuje medicinsku i stomatološku anamnezu, kliničke znakove aktivnosti karijesne lezije te određene testove koji nam pomažu u pronalaženju pacijenta s visokim rizikom od nastanka karijesa. Nakon detaljne anamneze i pregleda, pristupa se individualnom planiranju liječenja koji se mora uskladiti s djetetovim godinama, zrelošću i kooperativnosti. Mnogo je napora uloženo u razvoj modela za predikciju karijesa. Kako doći do apsolutno točnog modela, još nije riješeno jer nas već spomenuta složena etiologija karijesa ograničava u tome. Cariogram je jedna od naprednijih metoda pomoću koje možemo odrediti nastanak karijesa. Ona uzima u obzir indikatore rizika i biokemijske faktore koji utječu na nastanak karijesa. Najvažnija zadaća je identificirati visoko ugrožene pacijente, liječiti ih, provesti pojačane preventivne mjere i promicati interes u održavanju dobrog oralnog zdravlja.Caries is closely linked to the development of dental medicine as a science and has been a clinical discipline from its early beginnings. Given that caries has a biological substrate, it consequently possesses an unpredictable characteristic, as is always the case when viewing particular events in a live medium. Access to caries in clinical practice is based on an appropriate diagnostic system that includes a medical and dental history, clinical signs of caries lesion activity and particular tests that aid in finding patients at high risk of caries. A thorough history and physical examination is followed by an individual planning of treatment, which must conform to the child's age, maturity and cooperativeness. Much effort has been invested in developing a model for predicting caries. The issue of obtaining a completely accurate model has not yet been resolved because the already mentioned complex etiology of dental caries poses some restrictions. The cariogram is one of the more advanced methods that allows us to determine the onset of caries. It takes into account risk indicators and biochemical factors that influence the onset of caries. The most important task is to identify highly vulnerable patients, treat them, implement enhanced preventive measures and promote interest in maintaining good oral health

Volcanic glass - an ideal paleomagnetic recording material?

Volcanic glass is often considered an ideal recording material for paleointensities. Experiments to determine the ancient field intensity are time consuming and mostly have low success rates. Studies have shown that the usage of glassy samples can increase success rates very much as the remanence carriers are in or close to the single domain range. Further, effects like magnetic anisotropy and cooling rate correction can be corrected for. The aim of this thesis is to clarify whether an ideal behavior can be expected when working on volcanic glass. Studies were done on samples of different compositions (phonolite, pantellerite and rhyolite) and varying degrees of devitrification/hydration. Rock magnetic measurements were done to determine the remanence carriers of remelted glass samples of phonolitic composition. Single domain (SD) titanomagnetites were identied to carry the stable remanence and in the course of paleointensity experiments the validity of a cooling rate correction method that makes use of the natural cooling rate of the samples as determined from relaxation geospeedometry was shown. After correction the samples reproduce the intensity of the previously applied field. For the unhydrated samples from Montana Blanca, Tenerife (phonolitic composition, 2 ka old) and from Mayor Island, New Zealand (pantelleritic composition, 8 ka old) remanence carriers in or close to the SD range were found and high quality well defined paleointensities were obtained. Success rates of the paleointensity experiments were 70%. The results compare very well with other paleointensities from close-by studies at the respective times. These data support the ideal recording behavior of volcanic glass. Yet, rock magnetic and paleointensity experiments on devitrified and hydrated samples give contrary results: It was found that hydration and devitrification result in a loss of magnetic stability and remanence carriers, an increase in grain size of magnetic particles and a decrease of the "apparent" paleointensity. A possible explanation for these obsevations is a partial or full overprint of the original thermoremanent magnetization by a chemical remanence. It is therefore obvious that suchlike altered glasses are far from being ideal recorders. Great care has thus to be taken when sampling volcanic glass. If pristine glass is sampled, an ideal behavior during paleointensity experiments is probable and - as the here presented data suggest - a good estimate of the ancient field intensity is likely to be gained. If, however, the glass is unknowingly altered the determined paleointensities are prone to underestimate the true field value

Assessment of plate waste by weighing in two elementary schools in the City of Zagreb

Školski obroci pridonose dnevnom energetskom i nutritivnom unosu u djece. Ostatak hrane na tanjuru u školama ne predstavlja samo gubitak resursa i novaca, već ukazuje i na to da učenici nemaju adekvatan prehrambeni unos. Cilj ovoga rada bio je metodom vaganja izmjeriti ostatak ručka na tanjuru, a metodom Probaj i ocjeni utvrditi stupanj sviđanja variva od povrća učenika od 1. do 4. razreda u dvije zagrebačke osnovne škole (n=137). U prosjeku je bačeno 41% kruha, 27% variva od poriluka, 23% mesa i 7% pudinga u odnosu na serviranu porciju. Većina učenika (69%) varivo je ocijenila visokim ocjenama, a među onim učenicima koji nisu pojeli cijelo varivo jedan od najčešćih razloga nedovršavanja obroka bio je neprihvatljiv okus (36%). Energetska vrijednost prosječne porcija ručka nije u skladu sa Nacionalnim smjernicama za prehranu učenika u osnovnim školama, te djeca u prosjeku unose i do 50% manje energije od preporučenog. Potrebno je revidirati jelovnike i prilagodit ih s obzirom na energetske i nutritivne potrebe konzumenata školskih obroka.School meals contribute to the daily energy and nutrient intake of children. Plate waste in schools does not only represent a loss of resources and money, but it also indicates that the pupils dietary intake is inadequate. The aim of this research was to assess lunch plate waste by weighing, and vegetable meal preferences with the Taste and rate method, among pupils from 1st to 4th grade in two elementary schools in Zagreb. On average, 41% of bread, 27% of leek stew, 23% of meat and 7% of pudding was wasted. Most pupils (69%) graded the stew with high grades, while among those children who did not finish the stew one of the most common reasons was that they disliked the taste (36%). The energy value of the average lunch serving does not comply with the National guidelines for nutrition of students in elementary schools with children getting up to 50% less energy than recommended. It is necessary to revise the menues and adjust them accoring to energy and nutrient needs of the school lunch consumers

The Concept of Compulsory Military Service: A Comparison of France, Norway, and Finland

Predmet ovoga rada je prikaz i kompracija politika obveznog vojnog roka u tri europske države, Francuskoj, Finskoj i Norveškoj. Cilj je analizirati nekoliko država unutar europskog konteksta s obzirom na: utjecaj geografskih i geopolitičkih faktora na sigurnosne i obrambene strategije; različit vojno-politički položaj s obzirom na članstvo u političkim i vojnim savezima, odnosno NATO-u i Europskoj uniji; različite regionalne odnose, sigurnosno okruženje i različita povijesna iskustva te na koji način ti faktori utječu na politiku obveznog vojnoga roka, odnosno na model popunjavanja vojnih jedinica. Rad je zamišljen kao komparativna studija slučaja triju europskih država, a temelji se na pregledu već postojećih tekstova i istraživanja. U prvom dijelu rada definira se obvezni vojni rok, njegov povijesni razvoj i moderni trendovi. U drugom dijelu razmatra se Francuska i razvoj obveznog vojnog roka do njegovog ukidanja. Zatim se razmatra Norveška, obvezni vojni rok te njeno članstvo u NATO savezu. U četvrtom dijelu razmatra se Finska kao država izvan vojnih saveza i njena politika obveznog vojnog roka. Rad završava komparacijom ovih država te se zaključuje kako mnogi različiti faktori utječu na politiku obveznog vojnog roka.The subject of this paper is the presentation and comparison of compulsory military service policies in three European countries, France, Finland, and Norway. The aim is to analyze several countries within the European context with regards to the impact of geographical and geopolitical factors on security and defense strategies; different military and political positions with regard to membership in political and military alliances, namely NATO and the European Union; different regional relations, security environment, and different historical experiences, and how these factors affect the military conscription policy, or the model of military unit replenishment. The paper is conceived as a comparative case study of three European countries, based on a review of existing texts and research. The first part defines compulsory military service, its historical development, and modern trends. The second part discusses France and the development of compulsory military service until its abolition. Norway, compulsory military service and its membership in NATO are then discussed. The fourth part deals with Finland as a state outside the military alliances and its compulsory military service policy. The paper concludes with a comparison of these countries and concludes that many different factors influence the policy of conscription