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The same material about friction was covered by the same teacher in three different ways: using only verbal and textual means of communication (text group), using visual aids (diagram group) and using simple experiments (experiment group). The conceptual understanding of each group was evaluated using a test developed for this research. The scores were similar across the groups. HIGHLIGHTS We used friction examples to compare three methods for teaching physics: textual, visual and practical. The first group of students had the textual version of the lesson, with no drawings or diagrams. The second group of students had the usual class, in which the verbal explanation is accompanied by drawings and diagrams on the board. The third group had the complete bundle – verbal explanations, diagrams on the board, and a chance to conduct simple experiments. The effectiveness of teaching methods was evaluated using a conceptual test developed for this research. The scores of all groups were very similar.

Single slit diffraction is part of many high-school physics curricula throughout the world. In this study, we aimed to investigate whether high-school physics teachers from Bosnia and Herzegovina, Serbia and North Macedonia are adequately prepared to discuss with their students about various aspects of the single slit diffraction pattern, particularly about vertical length of diffraction fringes. To that end we conducted a written survey which included 57 high-school physics teachers. Besides asking teachers about students’ difficulties in learning about single slit diffraction, we also asked them to specify their own difficulties with this topic and required them to solve a conceptual task. Almost every second teacher believed that vertical length of diffraction fringes can be increased by changing shape or width of the slit and only 1 out of 57 teachers managed to correctly answer why diffraction fringes become shorter when we move away from the central maximum. We concluded that physics teacher education programmes should be changed to develop understanding of both, horizontal and vertical aspects of the diffraction pattern. To that end it is useful to provide learning opportunities which encourage combining ray and wave model of light.

This paper presents the effects of the Generalized Uncertainty Principle (GUP), i.e. its classical version expressed through the deformed Poisson brackets in the phase–space of a one-dimensional minisuperspace Friedmann cosmological model with a mixture of non-interacting dust and radiation. It is shown, in the case of this model, that starting from the specific representation of the deformed Poisson algebra, which corresponds to the change of the potential energy term of the oscillator, the size of the early universe can be related to its inflationary GUP expansion.

Students often have difficulties comprehending situations in which wave characteristics of light are manifested. After teaching wave optics, we studied the level of understanding of reflective diffraction of light with a group of secondary school students, and the phenomenon of diffraction in general. We analysed the possibility of using convenient reflexive diffraction gratings (compact discs and rulers with millimetre and half-millimetre markings) using suitable research school experiments which can be prepared. With appropriate methods of visualising the superposition of light waves, those experiments represent the basis for an appropriate conceptual change in the understanding the diffraction of light.

In this paper the interior of the Schwarzschild black hole, which is presented as a vacuum homogeneous and anisotropic Kantowski-Sachs minisuperspace cosmological model, is considered. Lagrangian of the model is reduced by a suitable coordinate transformation to Lagrangian of two decoupled oscillators with the same frequencies and with zero energy in total (an oscillator-ghost-oscillator system). The model will be presented in a classical, a p-adic and a noncommutative case. Then, within the standard quantum approach Wheeler-DeWitt equation and its general solutions, i.e. a wave function of the model, will be written, and then an adelic wave function will be constructed. Finally, thermodynamics of the model will be studied by using the Feynman-Hibbs procedure.

A vacuum homogeneous and anisotropic Kantowski-Sachs minisuperspace cosmological model is considered. In a classical case, Lagrangian of the model is reduced by a suitable coordinate transformation to Lagrangian of two decoupled oscillators with the same frequencies and with zero energy in total (an oscillator-ghost-oscillator system). The model is formulated also on noncommutative space.

Dimensional analysis is a simple, clear and intuitive method for determining the functional dependence of physical quantities that are of importance to a certain process. However, in physics textbooks, very little space is usually given to this approach and it is often presented only as a diagnostic tool used to determine the validity of dependences otherwise obtained. This paper presents the basics of dimensional analysis in two cases: the resistance force of the fluid that occurs when a body moves through it and the speed of propagation of waves on water. After that, a general approach to dimensional analysis based on the Buckingham theorem is shown. The material presented in the paper could be useful to both students of physics and physics graduates.

The main contribution of this paper is didactic adaptation of the biomechanical analysis of the three main lifts in powerlifting (squat, bench press, deadlift). We used simple models that can easily be understood by undergraduate college students to estimate the values of various physical quantities during powerlifting. Specifically, we showed how plate choice affects the bench press and estimated spine loads and torques at hip and knee during lifting. Theoretical calculations showed good agreement with experimental data, proving that the models are valid.

Application of the p-adic analysis and Green function in relativistic quantum theory is considered. Integrability of the free relativistic particle model is discussed. A convenient gauge is fixed. The Green function, as a corresponding propagator, are calculated in 4-dimensional p-adic Minkowski space. For this model, detailed calculation is performed for all three different cases: p ? l(mod)4, p ? 3(mod)4 and p = 2. .

Environmental problems arise from an interaction of man with nature Environmental physics uses a number of sub-disciplines of physics in order to solve this problem. This in turn necessitates the study of various aspects of the man-environment interaction through educational programs. In this paper we discuss the motives for teaching environmental physics and present some ideas of how to improve the position of this subject in the educational system in Serbia. The role of specific seminars in this field is emphasized.

We consider dynamics of a free relativists particle at very short distances treating space-time as Archimedean as well as no Archimedean one. Usual action for the relativistic particle is nonlinear. Meanwhile, in the real case, that system may be treated like a system with quadratic (Hamiltonian) constraint. We perform similar procedure in p-adic case, as the simplest example of a no Archimedean space. The existence of the simplest vacuum state is considered and corresponding Green function is calculated. Similarities and differences between obtained results on both spaces are examined and possible physical implications are discussed. .

p -Adic quantum cosmology is one of the considerable applications of p -adic quantum theory, which takes into account possible nonarchimedean (ultrametric) aspects of space-time. For this reason, we consider minisuperspace cosmological models in the framework of p -adic and adelic quantum mechanics. In particular, we investigate the de Sitter model and obtain p -adic and adelic wave functions, which are briefly discussed.

The paper considers the properties of space and time in quantum cosmology. It presented the basic ideas of the substantial and relational conceptions of space and time, as well the basic ideas of the continuity and discreteness of space and time. The basics of standard quantum cosmology, i.e. quantum cosmology formulated over the field of real numbers R, have also been presented. Quantum cosmology is the application of the quantum theory to the universe as a whole in the early phases of its evolution, when the universe was very small so that all the four interactions were practically unified. In order to obtain the maximum possible information from quantum cosmology it is necessary that it be "complete". The concept "complete" refers here to the formulation of the theory over the field of real numbers and the field of p-adic numbers Qp. Since p-adic numbers are generally not well-known, the idea of their introduction has carefully been considered. Within the p-adic quantum cosmology representing quantum cosmology over the field of p-adic numbers Qp, the main results concerning the de Sitter model have been presented. The consequence of this (complete) formulation of the de Sitter model is the radius discreteness of the universe.

We consider classical and quantum dynamics of a tachyonic system described by a DBI type Lagrangian and inverse cosh potential. This investigation is partially motivated by the string theory and D-brane dynamics, but mostly by their application in cosmological inflation. A formalism for describing dynamics of spatially homogenous tachyon scalar field with this kind of potentials is developed. Classical actions and corresponding quantum propagators in the Feynman path integral approach, both on real and nonarchimedean spaces, are calculated. Possibilities for a quantum adelic generalization of these models are noticed. Cosmological applications are pointed out and discussed.

p-Adic and adelic generalization of ordinary quantum cosmology is considered. In [1], we have calculated p-adic wave functions for some minisuperspace cosmological models according to the "no-boundary" Hartle-Hawking proposal. In this article, applying p-adic and adelic quantum mechanics, we show existence of the corresponding vacuum eigenstates. Adelic wave function contains some information on discrete structure of space-time at the Planck scale.

The imperative of today’s education in the field of physics and natural sciences is to overcome the conventional form of teaching which is mostly reduced to students’ repetition of the appropriate lessons. Having that in mind, we are more concentrated on involvement of students in the teaching process through stimulation of their individual way of thinking and the use of knowledge gained through their own experience. The paper describes in detail three geometric optics experiments that can be explained on the basis of knowledge about the linear propagation, reflection, refraction and total internal reflection of light. These experiments, although simple to perform, are of problem‐solving character because their results represent the paradox between the acquired knowledge and the already experienced one, thus attracting the students’ attention and making them more interested in the acquisition of knowledge.

A simplified model of tachyon matter in classical and quantum mechanics is constructed. p-Adic path integral quantization of the model is considered. Recent results in using p-adic analysis, as well as perspectives of an adelic generalization, in the investigation of tachyons are briefly discussed. In particular, the perturbative approach in path integral quantization is proposed., 11 pages

A motivation of using noncommutative and nonarchimedean geometry on very short distances is given. Besides some mathematical preliminaries, we give a short introduction in adelic quantum mechanics. We also recall to basic ideas and tools embedded in q-deformed and noncommutative quantum mechanics. A rather fundamental approach, called deformation quantization, is noted. A few relations between noncommutativity and nonarchimedean spaces as well as similarities between corresponding quantum theories on them are pointed out. An extended Moyal product in a proposed form of adelic noncommutative quantum mechanics is considered. We suggest some question for future investigations.

The significant matter for the construction of the so-called no-boundary proposal is the assumption of signature transition, which has been a way to deal with the problem of initial conditions of the universe. On the other hand, results of Loop Quantum Gravity indicate that the signature change is related to the discrete nature of space at the Planck scale. Motivated by possibility of non-Archimedean and/or noncommutative structure of space–time at the Planck scale, in this work we consider the classical, p-adic and (spatial) noncommutative form of a cosmological model with Friedmann–Robertson–Walker (FRW) metric coupled with a self-interacting scalar field.