In the experimental process of measuring liquid surface tension coefficient by pull-off method，there are many factors that influence the experimental results． Four factors that have significant influence on the experiment are summarized and analyzed by theoretical analysis，namely，the error of surface tension coefficient caused by temperature measurement deviation; Incorrect k value caused by rust or wear of weight leads to error of surface tension coefficient; The surface tension coefficient error is caused by the change of △U caused by the water on the ring，and the surface tension coefficient error is caused by the measurement error of the inner and outer diameters of the ring．The analysis results show that the surface tension coefficient measured by the experiment will gradually decrease with the increase of temperature，and its measurement error will be
aggravated with the increase of the number of rusty weights，the mass of water droplets attached to the ring and
the measurement error of inner and outer diameters．The research results can play a guiding role in reducing the
measurement error of liquid surface tension coefficient by pull-off method in the experimental teaching process
of college physics teaching．
Based on the Fourier transform and spatial filtering theory of spectrum, the theoretical analysis of the light intensity and phase modulation of Gaussian beam after spatial filtering by 4F system is carried out. The MATLAB mathematics software is used to simulate the image formed by the high-pass and low-pass filtering of the "light" screen after 4F system. The differential screen was designed by ourselves, and the edge enhancement effect was realized by changing the phase of the diffracted light. The simulation results are in good agreement with the experimental data. Through theoretical simulation, the physical connotation of Gaussian beam Fourier transform and spatial filtering optical phenomena is vividly and deeply revealed, which lays a foundation for the design and effect demonstration of functional filters.
We have established a model for the analysis of azimuthal-radial pendulum by Lagrangian mechanics. We list the I agrangian function of the system and consider the influence of air resistance. The theoretical trajectory of the azimuth-radial pendulum is obtained by numerical simulation.The influence of the weight' s mass , the releasing azimuth angle and the releasing radial angle on the maximum displacement in the direction of azimuth was investigated by using the method of controlling variables.The experimental results were in good agreement with the numerical simulation results , which further proved the correctness of our theory.
The determination of Young's modulus of wire is one of the important experiments in college physics experiment. This experiment comprehensively trains students' basic physical experiment skills, such as measurement, data processing and measurement skills. In this paper, the teaching content has been expanded. For the aspect of the method, the reference ruler is proposed to measure the distance between mirror rulers and the length of wire, which is difficult to accurately measure, so as to improve the measuring accuracy. For the aspect of the content, the research contents of elastic hysteresis property of materials are expanded by the characteristics of stress corresponding to strain when adding or subtracting weights; In terms of data processing, the least square method and item-by-item difference method are adopted to process the data, the young's modulus values obtained are 1.88454×1011 Pa and 1.88959×1011 Pa, respectively. The relative error between them is only 2%.
Based on the GGDC-B type silicon photocell comprehensive experimental instrument, the basic characteristics of silicon photocells were studied. Through our experiments, it is concluded that as the illumination increases, the output voltage and current of the silicon photocell gradually increase. In a certain range of illumination, as the load resistance increases gradually, the output current is still linear with the illumination. The smaller the resistance of the load, the larger the range in which the output current is linear with the illumination. In the visible range, the sensitivity of a silicon photocell increases with increasing wavelength.
It introduces an experiment of measuring charge-mass ratio of electron by the method of magnetron controlling. It was focus on analyzing the way of processing the experimental data. In addition, it presents the “Midpoint” method of dealing with experiment data systematically, combining the way of the “Half Saturation Current” and the “Intersection”. The charge-mass ratio of electron was about 1.65×1011 C/kg and 1.81×1011 C/kg with relative errors of 6.25% and 2.84% by using the method of half saturation current and intersection method, respectively. However, the charge-mass ratio of electron was about 1.74×1011 C/kg with relative errors of 1.14% by using the method of “midpoint”. It can be found that the method of “midpoint” can obtain charge-mass ratio of electron with higher precision compared with the method of “Half Saturation Current” and “Intersection”.
with the rapid rise and development of computer technology, Computers are being used more and more frequently in college physics teaching, and computer simulation has become the third important research method besides experimental research and theoretical research. This paper mainly uses a Matlab numerical simulation software to write a visual application. Image the Maxwell rate distribution function and adjust different parameters by setting. Intuitively and dynamically demonstrate the changing rules, supplementing and perfecting the shortcomings of traditional teaching. Enhance the effectiveness and interest in the learning process of physics knowledge, which improves students' initiative and enthusiasm to study.
Poisson bright spot is an important experimental phenomenon which be used for proving the fluctuation of light. Based on the Fresnel diffraction theory, the diffraction processes of Poisson bright spot were simulated by a Matlab program in a computer. The change tendency of the Poisson bright spot and its diffraction rings were studied by different wavelength of incidence light, diameter of the disk, and position of the receiving image. This study shows that single dark ring and multiple dark ring can be realized by suitable conditions, which has potential applications in micro-nano fabrications of semiconductors.
The experimental data of the pull-off method to measure the surface tension coefficient is calculated in detail，and the accuracy of the measurement results is better at room temperature．A single measurement was performed under variable temperature． Due to the low accuracy of the temperature control device of the instrument and the small change of the surface tension coefficient with temperature，the measured value of each temperature point has a certain deviation，but the change trend of the experimental results is basically the same．
The coefficient of liquid expansion is the ratio of the volume change to its volume at 0 ° C for every 1 degree Celsius change in temperature. In this paper, the experimental device for measuring the liquid expansion coefficient is assembled. The capillary and the temperature sensitive bubble are assembled into a container for the temperature sensitive liquid for experiment. Then, the constant temperature water bath is used as the device for changing the temperature of the liquid, the experimental data is recorded, the data is processed, and the water is obtained. And the coefficient of expansion of ethanol. The experimental conclusion has an important reference for the design and calibration of the thermometer. The error between the experimental results and the standard values is 2.9% and 3.0%, respectively, and the relative error is small, indicating that the experimental scheme is feasible.
