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    06 July 2026 Volume 45 Issue 4
      
    2025 Nobel Prize in Physics explained: A century-long journey of  quantum superposition from the microscopic to the macroscopic
    YU Yihan, LI Xinyi, XU Kai1, FAN Heng
    College Physics. 2026, 45(4):  1.  doi:10.16854/j.cnki.1000-0712.250720
    Abstract ( 87 )   PDF (753KB) ( 18 )  
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    The 2025 Nobel Prize in Physics was awarded to John Clarke, Michel H. Devoret, and John M. Martinis in recognition of their decisive contributions to realizing and controlling macroscopic quantum coherent states in superconducting circuits. Their work demonstrates that coherent superposition—a core feature of quantum mechanics—is not exclusive to microscopic particles but can also exist and be precisely manipulated in engineered artificial systems composed of billions of electrons. This article begins with the fundamental concept of quantum superposition, explains how decoherence blurs the line between the quantum and classical worlds, and describes how the laureates used superconducting circuits to achieve macroscopic energy-level quantization, coherent oscillations, and quantum tunneling—ultimately laying the physical foundations for modern quantum computing and quantum engineering.



    Brief analysis of superconductor maglev
    LI Jingqi1, 3, XU Yiyuan1, ZHANG Jiatian2, MA Jiyun2, ZHANG Jinsong3, QIN Mingyang3, ZHU Beiyi3, JIN Kui1, 3
    College Physics. 2026, 45(4):  5.  doi:10.16854/j.cnki.1000-0712.260006
    Abstract ( 47 )   PDF (673KB) ( 21 )  
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    Superconductors can exhibit captivating levitation and suspension phenomena on magnets, which go beyond simple diamagnetic explanations. This paper first demonstrates the key experimental phenomena and then explains the physical origins of levitation and suspension based on the relationship between magnetization and force. For quantitative description, we further employ the Bean model to calculate the internal flux distribution and macroscopic magnetization of superconductors under varying external magnetic fields, aiming to establish a classical physical picture of superconducting magnetic levitation. The paper seeks to provide a preliminary theoretical framework for superconducting levitation. Professional terms involved—such as type-II superconductors, magnetic hysteresis, and flux quanta(vortex)—are introduced to meet the needs of readers with diverse backgrounds and to lay the groundwork for subsequent indepth analysis.


    Measurement of microwave electric fields based on Rydberg atoms
    WU Lianglong, CHEN Jinyu, XIAO Mengzhuo, CHEN Haixia, WEI Dong
    College Physics. 2026, 45(4):  11.  doi:10.16854/j.cnki.1000-0712.250248
    Abstract ( 43 )   PDF (762KB) ( 11 )  
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    Rydberg atoms possess a large electric dipole moment and are highly sensitive to external electric fields, making them suitable for precise measurements of electric field strength. The electromagnetically induced transparency (EIT)AutlerTownes (AT) splitting effect based on Rydberg atoms exhibits a splitting width proportional to the target microwave electric field strength, serving as the primary atomicbased traceability standard for microwave electric field measurements. Experimental results demonstrate that the minimum measurable electric field strength of the AT splittingbased microwave electric field sensor is 3.7 mV/cm. This experiment holds significant value in university physics laboratory teaching: on one hand, students can gain a deeper understanding of atomic spectroscopy and electromagnetically induced transparency, enhancing their theoretical knowledge; on the other hand, by independently constructing the experimental setup, students’ handson skills are notably improved. The experimental apparatus presented in this paper is simple in structure, easy to assemble, and highly suitable for teaching purposes.

    Effect of inductance on current distribution in a parallel superconducting circuit
    ZHANG Jiangao1, 2
    College Physics. 2026, 45(4):  16. 
    Abstract ( 33 )   PDF (567KB) ( 17 )  
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    There is no electrical resistance in the superconductor. This raises the question of how the current is distributed in a parallel superconducting circuit. In this study, we derive and experimentally verify the governing rule for the current distribution in parallel superconducting circuits. A measurement system is designed to accurately assess the current distribution in the parallel superconducting circuits. Hall effect detectors are employed to measure the current intensity to prevent damage to the zero electrical resistivity of the parallel circuits. The experimental results confirm that the current distribution in parallel superconducting circuits is inversely proportional to their inductance.

    Visualization of nanoscale electric fields: a case study of singlemolecule  manipulation using a teachingfocused STM system
    ZHANG Xin1, CHEN Xiaorui2, YAN Chao1, WANG Hengtong1, GAO Jianzhi1
    College Physics. 2026, 45(4):  21.  doi:10.16854/j.cnki.1000-0712.250308
    Abstract ( 43 )   PDF (654KB) ( 8 )  
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    In modern education, it is an innovative attempt to integrate cuttingedge technology into high school laboratory teaching. Addressing the challenge of visualizing the microscopic mechanisms of electric field effects in physics experimental teaching, this study designs and implements a nanoscale singlemolecule manipulation experiment using a teachingfocused scanning tunneling microscope (STM). By utilizing a selfdeveloped STM system with an electric field control module, we establish a controllable experimental framework for the extraction, transport, and release of C60 molecules. The successful synthesis of (C60)7 clusters notably enhances interdisciplinary innovation capabilities. This approach transforms frontier technology into reproducible teaching experiments, providing a pioneering paradigm for the visualized teaching of microscopic physical phenomena.

    Derivation of mass-energy equation and relativistic momentum  through the redistribution of kinetic energy and momentum
    JIANG Kexia, Wu Yi, WANG Chunfeng
    College Physics. 2026, 45(4):  24.  doi:10.16854/j.cnki.1000-0712.250550
    Abstract ( 32 )   PDF (787KB) ( 10 )  
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    This paper reviews the derivation methods of the mass-energy equivalence and momentum relations from the original literature, which are logically rigorous but procedurally complex, limiting their application in modern textbooks. The authors propose a novel derivation scheme based on the concept of “redistribution of kinetic energy and momentum”. By introducing the photon concept and incorporating the Doppler effect, the transformation relationships of energy and momentum in different inertial frames during symmetric photon radiation are analyzed. This approach simultaneously derives the mass-energy equivalence and relativistic momentum relations without relying on electrodynamics. The method is logically clear and mathematically concise, making it suitable for courses with limited teaching hours. It helps students understand the intrinsic connection between mass, energy, and momentum, offering new insights for improving the teaching of related content.


    Apparent charge of a moving point charge and the Lienard-Wiechert potential
    LI Bo, YU Hui
    College Physics. 2026, 45(4):  34.  doi:10.16854/j.cnki.1000-0712.250338
    Abstract ( 34 )   PDF (758KB) ( 16 )  
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    The retarded potential of a continuous charge distribution and the Lienard-Wiechert potential of a moving point charge are both key and challenging topics in undergraduate electrodynamics courses. This study constructs examples of continuous charge distributions analytically solvable with elementary mathematics, and presents graphical analyses of the charge distribution and total charge perceived by an observer. These examples are intended to aid in understanding the semi-intuitive derivation of the Lienard–Wiechert potential as presented in Griffiths classic textbook. This work helps clarify that the perceived charge is unrelated to relativistic length contraction, provides an intuitive picture of the finite speed of electromagnetic interaction transmission, and deepens the understanding of point charges in classical electrodynamics. 


    A logical process for deriving the Lorentz transform
    GUAN Congsen, FAN Huaxi
    College Physics. 2026, 45(4):  39.  doi:10.16854/j.cnki.1000-0712.250506
    Abstract ( 37 )   PDF (753KB) ( 13 )  
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    This article starts from the two basic principles of special relativity and, combined with spatial symmetry, provides a new detailed derivation process for the Lorentz transformation formula. Compared to the usual proofs in textbooks, this method utilizes spatial symmetry to clarify certain issues without introducing the concept of ‘interval.’ The paper carefully discusses the method for setting up coordinate systems and their impact on the transformation equations, demonstrating the reasons why the transformation formulas for x′ and t′ are independent of y and z, and why the transformation formulas for y′ and z′ are independent of x and t. These issues are not explained in standard textbooks. This proof process serves as a reference for students and teachers in learning or teaching university physics and physics majors.


    The holographic property of electromagnetic laws
    SONG Litao1, HE Jie2, WANG Jiefang1
    College Physics. 2026, 45(4):  44.  doi:10.16854/j.cnki.1000-0712.250345
    Abstract ( 34 )   PDF (501KB) ( 12 )  
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    This paper first introduces the concept of holographic property by analogy with the holographic principle. Then, starting from Stokes’ theorem and Gauss’ theorem in vector field theory, the holographic characteristics of electromagnetic laws is discussed. Finally, combined with the holographic property of electromagnetic laws, the physical essence of the uniqueness theorem of the boundary value problems of electrostatic fields and magnetostatic fields, as well as the boundary value definite solution problem electromagnetic wave fields, is analyzed. The results demonstrate that the uniqueness theorems of the electrostatic fields and magnetostatic fields, along with the boundary value definite solution problem electromagnetic wave fields, can all be regarded as concrete manifestations of the holographic property of electromagnetic laws in practical applications. This approach thereby helps students better understand the physical essence of these theorems and the HuygensFresnel principle.

    Interaction of gas molecules and gas-liquid phase transition
    CAO Wan-qiang, PAN Rui-kun, ZHANG Lei
    College Physics. 2026, 45(4):  47.  doi:10.16854/j.cnki.1000-0712.250195
    Abstract ( 29 )   PDF (494KB) ( 12 )  
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    The critical characteristics, condensation and supercoolingphase transition processes of real gas are derived in terms of the van der Waals equation. The results of analysis indicate that the stronger attraction and the weaker repulsion between molecules correspond to the higher phase transition temperature. The supercooled gas, due to the pressure resistance, below the critical temperature is metastable, which requires an external induction to overcome the resistance to conduct phase transition. To reduce the temperature will decrease the resistance and increase the volume shrinkage from supercooling state to phase transition point. The faster the temperature drops, the faster the phase transition of the supercooled gas will be. The influence of pressure on the gasliquid coexistence line has a discrepancy of a correction factor from that in the ideal gas. 


    Study on the electrical characteristics of an n-T type resistor network with feedback resistance
    TAN Zhizhong1, 2, YANG Jianhua1, 2, ZHANG Hua1, 2
    College Physics. 2026, 45(4):  50.  doi:10.16854/j.cnki.1000-0712.250478
    Abstract ( 22 )   PDF (509KB) ( 8 )  
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    The arbitrary n-order T-shaped resistor network (TRN) has significant value in the fields of circuits and microwaves. The article considers the electrical characteristics (including equivalent resistance and voltage at any node) of an n-order TRN with feedback resistor, achieving method extension and theoretical innovation. The main research method adopted is to establish recursive equation models and boundary condition equation models with node voltage as a variable. Through rigorous mathematical calculations, the general and specific solutions of the differential equation are derived, and the voltage analytical formula for any node of the TRN is derived. At the same time, the equivalent resistance formula between any two nodes is derived, and the special case of the conclusion is analyzed and discussed.

    Spatial distribution of the electrostatic field generated by a line charge on a Penrose kiteshaped tile#br#
    HAO Qinghai, ZHANG Hongyan, CHAO Minglu, TAN Hongge, YANG Xiong
    College Physics. 2026, 45(4):  54.  doi:10.16854/j.cnki.1000-0712.250342
    Abstract ( 38 )   PDF (929KB) ( 10 )  
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    Linear charge, as a classical model of electrostatic fields, holds significant importance in both teaching and research on electrostatic field distributions. Traditional models primarily focus on periodic or regularly geometric line charges, while the Penrose tile provides an ideal model for studying aperiodic line charges. In this paper, we select the Penrose kiteshaped line charge—an aperiodic yet longrange ordered planar tiling structure—to derive the electric field intensity at any arbitrary point in threedimensional space. This derivation is based on the electric field intensity formula for charged line segments and the superposition principle, employing vector field translation combined with rotational operations. The electric field distribution of the kiteshaped line charge is visualized, and the variation patterns along with their physical implications are analyzed. Using an adaptive Simpson′s integration algorithm, the potential distribution of the kiteshaped line charge is calculated. Within the plane containing the kiteshaped structure, equipotential surfaces are densely clustered near vertex regions, while becoming sparsely distributed and parallel to the charged line segments near midpoints of each edge, consistent with the electric field intensity distribution characteristics.

    Discussion on voltage measurement in vortex electric field
    CAO Jiangwei, WANG Hui-cui, ZHAO Lingyi
    College Physics. 2026, 45(4):  58.  doi:10.16854/j.cnki.1000-0712.250382
    Abstract ( 22 )   PDF (652KB) ( 10 )  
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    Vortex electric field (VEF) is one of the difficulties in the course of “Electromagnetics”. Although the loop integration and curl can accurately describe its differences from the electro-static fields (ESF), the unglamorous mathematical formulas cannot help students to understand their physical essence. Walter Lewins demonstration experiment on voltage measurement in a VEF intuitively presents the difference between VEF and ESF, but it also brings many doubts to students. This article discusses the distribution of electric field and charge accumulation in a conductor circuit in a VEF under equilibrium, and answers the question of what the “voltage” measured in a VEF is. These analyses are beneficial for deepening students understanding of the concept of VEF and its differences from ESF, while it also cultivates the scientific spirit of seeking the essence through phenomena.


    Overcoming teaching challenges in electrodynamics based on physics research methods#br#
    ZHANG Yue
    College Physics. 2026, 45(4):  63.  doi:10.16854/j.cnki.1000-0712.250319
    Abstract ( 27 )   PDF (458KB) ( 12 )  
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    The significant difficulty in teaching Electrodynamics is a common issue in university physics education. Based on systematic research from years of teaching experience, this paper identifies the root cause of this pedagogical challenge: traditional teaching methods fail to effectively convey the exploratory thinking characteristic of theoretical physics, which is marked by a “hypothesis-verification” approach. Given the constraints of existing curricula, which make it difficult to offer a separate course on the history of physics, this study proposes a teaching reform strategy embedded within standardized textbook content. The approach involves organically integrating the research paradigm of theoretical physics into the knowledge delivery process, achieving a deep fusion of subject matter and physics research methodology. Using case studies—such as the proposal of the displacement current hypothesis, the solution to electrostatic boundary-value problems, and the establishment of retarded potentials—the paper elaborates on practical implementation pathways for exploratory thinking in teaching. Finally, through an evaluation of teaching outcomes, the study summarizes transferable pedagogical insights and offers suggestions for further improvements.

    Teaching reform of thermodynamics——ideological and political education with moral education as the core#br#
    QU Bo
    College Physics. 2026, 45(4):  70.  doi:10.16854/j.cnki.1000-0712.250653
    Abstract ( 26 )   PDF (458KB) ( 9 )  
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    Thermodynamics, as a core course in the physics major, not only encompasses rich scientific knowledge but also carries profound philosophical ideas and value connotations. Based on the concept of curriculum-based ideological and political education, this paper explores how to organically integrate ideological and political education elements into thermodynamics teaching, achieving the unity of knowledge transmission and value guidance. By delving into the scientific spirit and patriotic sentiments in the history of thermodynamics development, the philosophical thinking embodied in thermodynamic laws, and the ecological perspective reflected in the entropy increase principle, a “knowledge-capability-socialist core values” tripartite teaching model is constructed. This paper proposes specific implementation strategies such as case-based teaching, thematic seminars, extracurricular practices, and scientist story sessions, aiming to cultivate students scientific literacy, social responsibility, and patriotic sentiments, providing references for the ideological and political construction of major courses.

    Analysis of application and effect of AI assisted hybrid physics teaching
    DAI Jun
    College Physics. 2026, 45(4):  73.  doi:10.16854/j.cnki.1000-0712.250242
    Abstract ( 24 )   PDF (954KB) ( 8 )  
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    Online and offline blended teaching has become the main form of physics teaching style, but the survey found that the online resources of blended teaching have problems that are difficult to solve, such as insufficient interactivity and innovation, learning effect and information differentiation, and low achievement of abstract knowledge comprehension. Based on the current artificial intelligence AI open source tools, this paper explores the use of AIassisted experiment design innovation tasks embedded in blended teaching, through the stepbystep design of independent exploration experiments, to realize the optimization of experimental methods and details by AI technology, promote students' active learning in the process of blended teaching, improve students' ability to realize AIassisted physical experiment design exploration based on personal learning characteristics, and enhance learners' physics situational experience. The results of the questionnaire survey show that the students' knowledge comprehension, memory and internalization, innovation and collaboration ability, and positive learning emotion have been significantly improved by AIassisted experimental physics scenario construction.

    Design and research of liquid refractive index measuring device based on linear CCD
    MENG Xiang-yu1, WANG Shuo-yan, KE Ju-yang, SHI Yu-hang, ZHANG Ji-yuan, YU Yin
    College Physics. 2026, 45(4):  78.  doi:10.16854/j.cnki.1000-0712.240269
    Abstract ( 17 )   PDF (769KB) ( 5 )  
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    In order to measure the refractive index of liquid accurately, quickly and conveniently without contact, this paper presents a scheme to measure the refractive index of transparent liquid by using refraction method and linear CCD, and designs a new device to measure the refractive index of liquid. The optical path of the device is precisely designed and applied to the measurement of liquid refractive index, and the measurement results are quantitatively analyzed. The relative error of refractive index of ethanol solution with different concentration is less than 0.6%. The device has the advantages of simple structure, good portability, simple operation and accurate measurement, and achieves high precision measurement of refractive index of transparent liquid.

    Calculation of dielectric constant for complex structures #br# based on coordinate axis transformation#br#
    QI Ningwei1, LI Sihan1, ZHANG Yang2, LIU Jun1
    College Physics. 2026, 45(4):  84.  doi:10.16854/j.cnki.1000-0712.250309
    Abstract ( 13 )   PDF (509KB) ( 2 )  
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    Crystals exhibit higher structural symmetry, which influences the macroscopic physical properties of crystals. As an important physical quantity, dielectric constant can be effectively simplified through theoretical calculations. Furthermore, theoretical calculations can simplify experimental measurements. In this work, a method of rotating coordinate system is proposed, basing on the dielectric constant of crystals as a secondorder tensor. To be more intuitive, the dielectric constant of the crystal can be calculated. Taking the regular tetrahedral crystal structure as an example, the symmetry operations on the crystal in the new coordinate system can achieve rotation matrix. Consequently, the degradation of the dielectric tensor is achieved. Compared with the existing methods, this approach substantially mitigates the empirical limitations and mathematical abstraction. The whole derivation visually demonstrates the degradation of the crystal dielectric constant, while simultaneously deepening students comprehension of the physical properties of the dielectric constant and advancing their theoretical calculation ability. 

    Average relative speed of ideal gases under Boltzmann, Fermi, and Bose distributions#br#
    HUANG Jin-long, LI Ning, WANG Fei, HU Hai-yun , ZHANG Yong-you
    College Physics. 2026, 45(4):  87.  doi:10.16854/j.cnki.1000-0712.250299
    Abstract ( 10 )   PDF (517KB) ( 2 )  
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    The average relative speed of gas molecules is a core physical quantity for understanding the transport properties of gases. This work derives expressions for the average relative speed of ideal gases under three common statistical distributions—Boltzmann, Fermi, and Bose distributions. For the Boltzmann distribution, corresponding to Maxwell distribution, the analytical solution of the average relative speed is rigorously derived. At absolute zero temperature, the average relative speed and average speed of an ideal Fermi gas are u=3635vF and v=34vF (vF is the Fermi rate), respectively, while both the average relative speed and average speed of an ideal Bose gas are zero. At non-zero temperatures, these quantities need to be solved via numerical integration. Calculation results show that the average relative speed and average speed are entirely determined by the velocity distribution law, which provides an important supplement to thermal physics teaching related to the kinetic theory of gases.


    Reflection and refraction of vortex beams
    DENG Di-wen, YANG Yuan-jie
    College Physics. 2026, 45(4):  91.  doi:10.16854/j.cnki.1000-0712.250293
    Abstract ( 18 )   PDF (713KB) ( 2 )  
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    As a special optical field carrying orbital angular momentum, vortex beams have demonstrated significant application potential in optical manipulation and optical communication in recent years. While reflection and refraction represent the most fundamental optical phenomena in nature, vortex beams exhibit unique reflection and refraction mechanisms distinct from conventional light. This review article first presents the fundamental concepts of vortex beams, then analyzes their distinctive phenomena during reflection and refraction, with particular emphasis on the theoretical mechanisms underlying the vortex-induced additional Goos-Hnchen shift and Imbert-Fedorov shift. Finally, we conclude with a prospective outlook on the potential applications.


    Experimental method for ultrasonic flaw detection using square-wave modulation waves
    XIE Rong-xue, XIN Zhi-hui, ZENG Jian-xiang, BAI Xin-lv, WU Sheng-feng, YIN Yi-wen, CUN Zhi-yang
    College Physics. 2026, 45(4):  98.  doi:10.16854/j.cnki.1000-0712.250339
    Abstract ( 12 )   PDF (1104KB) ( 2 )  
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    To enhance the measurement accuracy and operability of the ultrasonic flaw detection experimental device,the flaw echo method in the pulse reflection technique and the concept of square-wave modulation waves are used. A semi-automated ultrasonic flaw detection system is built by integrating a PicoScope 6000E series oscilloscope, a fixed device for ultrasonic flaw detection, probes, etc. This system generates square-wave modulation waves through amplitude keying method. The oscilloscope then receives and analyzes the echo signals. Subsequently, Matlab performs wavelet denoising and B-scan analysis to determine the depth and specific position of the defect. The experimental results show that the relative depth error of a 10mm deep planar defect does not exceed 2.02%; The relative depth error of a 13.5mm deep circular hole defect is within 1.53%; The relative position error of a 10mm deep and 2mm wide plane defect is less than 1.49%. The improved device effectively enhances measurement accuracy and operability.

    Research on the strategies of leading middle school science popularization by cuttingedge technology under the core literacy——taking gravitational wave detection as an example
    CAO Zhenyu, WU Yuan, GUO Jinxian, CHEN Liqing
    College Physics. 2026, 45(4):  104.  doi:10.16854/j.cnki.1000-0712.250274
    Abstract ( 12 )   PDF (1173KB) ( 2 )  
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    Based on the demand for cultivating core literacy and the requirements of the compulsory education curriculum standards for the popularization of cuttingedge technologies, this paper focuses on the strategic issues of integrating cuttingedge technologies into middle school science popularization education. The research adopted the methods of questionnaire survey and interview, and found that there are problems such as narrow coverage, insufficient attention from families and schools, and broken content connection in current popular science. Based on this, from the perspective of core literacy, the curriculum strategies of experimental demonstration, game interaction and exercise detection are proposed. Taking "Laser interferometer detection of Gravitational Waves" as an example, the "Ripples in Time and Space" curriculum case is designed. Practice shows that the relevant strategies have effectively enhanced the effect of popular science education and are feasible. The research has constructed a multidimensional path for the integration of technology and the classroom, providing a replicable practical model for the teaching design of science popularization education in middle schools and facilitating the development of students' scientific literacy.




    The differences between university and high school mechanics from the  perspective of problemsolving methods
    LIU Shuxin
    College Physics. 2026, 45(4):  113. 
    Abstract ( 9 )   PDF (715KB) ( 3 )  
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    By comparing the problemsolving methods in mechanics, this paper analyzes the differences between college mechanics and high school mechanics from multiple perspectives, hoping to provide some reference for the selection of textbooks, the optimization of teaching contents, and the configuration of the scope and difficulty of exercises.