This paper investigates the intriguing climbing motion of magnets proposed in Problem 4 of IYPT 2025. The results show that the climbing motion originates from periodic stick-slip interactions. A theoretical model based on the magnetic charge method is established, and an experimental apparatus is constructed to systematically study the effects of the parameters of neodymium magnets and ferromagnetic rods. The results show that, within the critical range, the climbing velocity first decreases and then increases with increasing magnet length and ferromagnetic rod diameter. The climbing velocity decreases as the remanence of the magnet increases. In addition, as the distance between the constraint point and the magnet or the magnet diameter increases, the climbing velocity first increases and then decreases. The theoretical predictions agree well with the experimental results, providing a clear explanation of the physical mechanism and main influencing factors of the climbing motion.

Digital oscilloscope experiment is an important basic experiment in college physics experiment course. In this paper, we introduced the basic principle and experimental method of digital image reconstruction on digital oscilloscope in detail based on principle of XY mode in the digital oscilloscope, and built the experimental platform and successfully achieved the function to display images on digital oscilloscope. The experimental model provided in this paper includes multi-disciplinary knowledge such as Lissajous graph and digital image information processing methods, can be serving as an extension of the conventional physics experiment project.

This article independently designed a demonstration experimental instrument for water wave interference diffraction, which was enhanced by the light shadow method to demonstrate the effect of water wave interference diffraction. And the interference diffraction phenomenon under different conditions such as vibration frequency and diffraction slit width was studied, and the principle of this phenomenon was deeply explored. At the same time, this article developed a visual virtual simulation experiment of water wave interference diffraction based on Matlab, which has the advantages of graphical and intuitive. The rationality of the simulation experiment was verified through comparison with the demonstration experiment phenomenon. Simulation experiments can be better applied to demonstrate in university physics classrooms. The research results can promote the research and application of physics related fields, and are of great significance for promoting the development of related fields.

This paper designs three methods of the earth's radius measurement, the sunset time difference method, the sun elevation difference method and GPS positioning method, which is in the context of COVID-19 outbreak and based on the smart phone. These experimental methods provided in this paper don't need professional physics experiment measuring tool and can be completed at home. The earth radius measured by the sunset time difference method and the sun elevation method are 6246km and 6239km with the measuring relative errors 2.0% and 2.1%, respectively. In the GPS positioning method, three point taking methods are designed including the point taking at the same longitude, at the same latitude and any point. The measured earth radius are 6432km, 6400km and 6343km respectively, and the measuring relative error can reach 1.0%, 0.5% and 0.4% respectively. The error accuracy of all methods in this paper can meet the requirements of basic physics experiment course design, and the measurement accuracy of GPS positioning method is obviously better than sunset time difference method and solar elevation method. At the same time, the main influencing factors of measurement error are also analyzed.