In view of the dispersion phenomenon in the measurement of liquid refractive index by prism total reflection method，the original light source of sodium or mercury lamp was replaced by a laser，and the extinction phenomenon is observed by a camera，thus eliminating the influence of the complex spectral line on the measurement． Several liquids’refractive indexes under different wavelengths were measured with the improved device．The results show that the measured values are in accordance with the references with the relative uncertainty less than 0． 1%． The improved experimental method is easy to operate and has high accuracy，which has further application value．

College physics experiment(CPE)teaching is an important teaching method to consolidate the basic knowledge of college physics and cultivate experimental methods and innovative skills． It discusses how to introduce the resonance phenomenon in whispering gallery mode microspheres，a popular research topic，into CPE teaching． Utilizing the measurement experiment of the resonance mode in whispering gallery mode microspheres to carry out a complete and novel experimental teaching design and experimental process，which could enrich the CPE teaching content．At the same time，it aims to improve students’ability of analyzing problems，practicing and creative thinking．

Teaching comparative research is an important method of teaching research and an important teaching practice in line with the requirements of teaching innovation and development in higher education in the new era．The comparative research of experimental teaching includes teaching research activities from many aspects，such as teaching idea，system，content and method．By selecting the moment of inertia of rigid body，an important physical quantity，the similarities and differences between the tri-linear pendulum method and the torsional pendulum method are compared in detail，from the experimental principle，experimental content，

experimental operation and data processing． This kind of teaching comparison has important practical significance for improving the quality of education and teaching and enhancing students’innovation ability．It is worth extending to other experiments of physics experiment course．

Based on the relationship between solution concentration and dielectric constant，this experiment uses the FDC2214 capacitance sensor to measure the capacitance parameters of solutions as the dielectric medium，achieving real-time measurement of solution concentration without contacting the solution．At the same time，based on the specific gravity method，a pressure sensor is used to monitor the mass parameters of the solution in real-time to verify the accuracy of the capacitance method．Finally，a device for real-time automatic measurement of solution concentration and automatic configuration of specific concentration solutions is designed．Glucose solution is used as an example in the experiment，and the experimental results and errors are analyzed，showing a measurement error of less than 1%．Compared with existing methods and devices，this device is not only more convenient and practical，but also has low cost and good scalability．Other functions can be added according to actual application needs，which can serve a wide range of fields such as life，production，teaching，and research．

There are many ways to measure surface tension，of which the pull-out method is a simple and effective one．Based on pull-out method，this experiment measures the surface tension coefficient by changing the sediment content and temperature of the river water to explore whether the measured value of the liquid surface tension coefficient will be effected as the sediment content and temperature changes．And the variation of surface tension coefficient of river water in clear and turbidity state is compared and analyzed．According to the analysis of the experimental results，it can be seen that the measured value of liquid surface tension is

related to the change of sediment content and temperature，and the surface tension coefficient of the river water in the turbidity state is generally greater than that in the clear state．

In view of the many shortcomings of the existing rainbow and neon demonstration devices，combined with the optical principle，a new demonstration device for rainbow and neon reappearance is designed by using the physical phenomena of light refraction，reflection and dispersion．By placing one or two reflectors in the water tank，the light can be controlled to reflect once or twice in the water，and then refract out of the water，producing dispersion and forming clear rainbow and neon phenomena．The device realizes the reappearance of rainbow and neon and the quantitative study of influence factors．It has the advantages of simple structure，simple operation and obvious phenomenon． Through the demonstration of the device，students can better understand the optical phenomena in the atmosphere and the formation principles and laws of rainbow and neon．

The Frank-Hertz experiment plays an important role in students’learning and understanding of quantum phenomena．Through theoretical derivation and experiments，the movement of electrons in F-H tube is studied，and the influence of reverse voltage and acceleration voltage on current intensity is analyzed on this basis．The influence of the first grid voltage on the electron energy is analyzed，and the effect of the grid voltage on the current intensity is studied through a large number of experiments，and the possible reasons for this phenomenon are proposed．This has certain inspiration for physics experiment teaching．

Three forms of sawdust can be formed by longitudinal cutting，including ribbon-shaped chip，plate-shaped chip and spiral chip．Based on the basic law of deformation，the forming mechanism of the ribbon-shaped chip is analyzed by using the beam bending model．Based on the principle of motion synthesis and decomposition，the shear stress model is used to explain the formation of spiral chip．The research content originates from the physical problems in production and life，and its research method is conducive to breaking through the influence of the thinking set in the teaching and learning of college physics，which is bounded by books and classroom．It can also provide valuable references for the scientific innovation training of college students majored in physics．

With the development of fast-paced life in today’s society，contemporary students increasingly ignore the importance of time management． They spend a lot of time in the fragmented entertainment that originally planned to watch only a few videos and play only a few games，which has a huge impact on their original study and life． To more effectively reflect the passage of time，the electronic hourglass circuit is specially designed to simulate the fall of sand in the hourglass by controlling the light beads．The electronic hourglass circuit simulates 30 seconds of normal hourglass dropping at non-hourglass time to remind people of the value of time．To cherish fragmented time，make a short time backtrack at the whole time，lower sand grains fall back to the upper hourglass again，and play a song and change the color of the lamp beads．This process is the same as 30 seconds，to remind people that time never goes back，people should pay attention to time management and make good use of time．

Poisson bright spot is a classic optical phenomenon caused by light diffraction，which is used as a typical demonstration experiment in the college physics for proving the wave character of light．The diffractions of circular screen are numerical calculated． And the influences of several parameters are systematically analyzed，including wavelength l，radius of circular screen Ｒ，distance between circular screen and receiving screen z，and roughness of the edge of circular screen．The results show that the number of Fresnel half-wave zones k is an important parameter．For the values of k that supporting high levels of Poisson bright spot intensity and contrast，the smaller k is supposed to benefit the demonstration．

This experiment explored the technology of measuring the surface tension of viscous liquids using the suspension drop method．By using micro injection control technology and combined with continuous image acquisition methods for dynamic processes，the droplet morphologies at different liquid volumes were obtained．The surface tension coefficient of silicone oil was calculated using the critical state image at the equilibrium case between droplet surface tension and gravity．Compared with the standard value，the relative error of the measurement data is about 4%．

Accurate temperature control is the key to measuring the temperature coefficient of metal resistance．Based on a temperature control device composed of PTC heating plate，micro-controller，temperature sensor，metal cavity，etc．，to achieve heating，temperature control，and temperature measurement of enameled copper wire．The improved experimental device has accurate temperature control，good linearity of experimental data．Linear correlation coefficient Ｒ 2 is over 0．999，and the measurement result is much closer to the theoretical value．

In conventional experimental teaching college physics，the interferometers operated with two-beam interference principle were constructed based on the spatial light structure．Due to the high cost and high losses in optical power of the interferometers，it is difficult to preserve them during the college teaching process．However，the panda polarization-maintaining optical microfiber interferometers have the merits of compact size，high stability and high refractive index sensitivity of 1 631 nm/ＲIU，high temperature sensitivity of －0．99nm/℃，and high measurement accuracy，they can be more suitable for applying in college teaching．Moreover，by fabricating the optical microfiber device and performing the measuring experiments，the operational ability of students can be improved，and the students’project learning interests can also be excited．It can also lay a solid foundation for the further experimental teaching research of novel optical fiber devices and their novel sensing applications．

The twenty-first century is facing a major issue of energy crisis，the country and enterprises urgently need to upgrade the energy structure and transform the energy mode． Gravity energy storage method is an important type of mechanical energy storage method，which is a clean energy storage method that converts gravitational potential energy into electrical energy and stores the electrical energy． A small gravity energy storage device was homemade in the laboratory，and the structure of various parts of the traditional device was optimized for equipment improvement．The effect of heavy mass，rise height and other unknown conditions on the efficiency of electrical energy conversion was investigated using a gravity energy storage device，which has the advantages of reducing experimental costs，saving time and facilitating multiple measurements compared to large gravity energy storage devices．In addition，because of the detachable and portable features of this device，it can also be used for teaching demonstrations and popular science displays．

By measuring the precession of the spiral micrometer head，combined with the charaon the experimental principle of Michelson interferometer，a special rotating device is added to the measurement optical path，which converts the tiny rotation of the cuvette containing the transparent liquid into the precession of the spiral micrometer，and accurately controls and records the start and end positions of cteristic change of the hyperbolic diffraction pattern formed，the refractive index of the solution to be measured is calculated，and then the linear relationship curve between the refractive index and the solution concentration is established， which realizes the accurate measurement of the liquid concentration，which not only expands the application scope of the Michelson interferometer，but also innovates the experimental teaching content of the Michelson interferometer．

Design a fall reminder device for the elderly based on STM32 single-chip microcomputer，this device is composed of STM32F429BIT6 controller as the core，using buzzer and gyroscope as alarm device，through GPS(Global Positioning System)positioning and communication module to transmit location SMS to the user’s children．The gyroscope used in this device is a three-axis accelerometer，by comparing the measured tilt angle with the set threshold to determine whether the elderly have fall behavior，if there is a fall behavior，it is through STM32 to pull up the corresponding pin level，the buzzer accepts the command to start the alarm，while the GPS module captures the user’s real-time location and sends it to the ATK-IDM750C module，and uses the AT command to send a text message containing the detailed location of the elderly to the user’s children．This system helps to protect the personal safety of the elderly，and is safe and efficient，reliable data，convenient and accurate，greatly improving the rescue efficiency of the elderly after falling，and can effectively protect the personal safety of the elderly．

In the digital electronic technology，“logical not”symbols have different representations，and their meanings are not uniform．It leads confusion in studying and application of logic circuits and logic devices．An argumentation is induced for the usage of “logical not”in logical circuit． The correctness of the way and meaning of“logic not”symbol in digital logic circuit are analyzed．The similarities and differences of "logic not in different logic circuits are summarized，and the teaching method of digital logic circuit is strengthened．

In modern college physics experiments，how to correctly process experimental data is a crucial step，and using software to process relatively complex experimental data can often make the results more accurate． Python is the most widely used computer programming language，but its application in physics experiments is relatively rare．Taking the Michelson interferometer experiment as an example，we discuss in detail how to use Python to achieve data processing，and compare the results obtained by processing data with traditional methods．The results show that the accuracy of the relevant parameters obtained by using Python is higher．In

addition，visualization images of interference circles are achieved through Python simulation，which helps to deepen the understanding of the essence of the experiment．Therefore，using Python to process college physics experimental data is worth further research and promotion．

One of the most important classical experiments in college physics，the photoelectric effect experiment proves the quantum properties of light．However，due to the limitations of experimental conditions and technical level，it is impossible to visualize experimental phenomena．Here，the photoelectric effect process is simulated based on the particle tracking module of Comsol software．The simulation can achieve the following functions:1)Ｒesearch can be carried out by adjusting parameters such as incident wavelength (frequency)，anode voltage，cathode work function，electrodes distance，and cathode emission current;2)The trajectory of electrons under different voltages can be simulated and displayed;3)Through the relationship curves between photocurrent and anode voltage and cathode emission current，the cut-off voltage is obtained to verify the basic laws of photoelectric effect．Students will have a deeper understanding and understanding for the process and laws of photoelectric effect through the application of this model．

Compared with the traditional multi-rotor UAV，the bicopter has stronger maneuverability and endurance，but the sensor measurement error will affect the control precision．In response to this problem，in terms of the overall structure，the bicopter test prototype was built and the dynamic model was deduced;In terms of control algorithm，the error compensation algorithm of the triaxial accelerometer is developed independently，and the improved cascade double closed-loop PID algorithm is formed by combining the algorithm with the traditional PID control algorithm innovatively，which can realize the suppression of the

cumulative error of the measured value of the triaxial accelerometer，at the same time，30 system control simulations were carried out by Simulink．The simulation results show that the improved cascade double closed-loop PID algorithm can theoretically reduce the overshoot of Y-axis displacement，roll Angle，pitch Angle andyaw Angle by about 78%，26%，19% and 44%，respectively．In the aspect of experimental measurement and control，a test prototype + measurement and control ground station system was built，and 10 groups of air hover comparison experiments were finally completed．The experimental results show that the steady-state errors of hover height，roll Angle，pitch Angle and yaw Angle of the improved PID algorithm are reduced by 35．68%，49．04%，2．33% and 55．96% compared with the traditional PID algorithm，which verifies the accuracy and actual effectiveness of the improved control algorithm．

College physics experiment is an important practical course to consolidate relevant basic theoretical knowledge．Combining cutting-edge scientific research content with physics experiment is helpful to cultivate students’research interest and scientific innovation ability．Important scientific theorems in the field of gas detection are analyzed and studied． Through the establishment of LabVIEW simulation experiment system，students are guided to independently explore the physical significance of relevant parameters and exercise their ability to discover and solve problems．

High-purity germanium (HPGe)detector is one of the important equipment for γ radioactivity analysis．HPGe detector experiment is crucial to the talent cultivation of nuclear science．Based on the teaching demand of HPGe detector experiment in School of Nuclear Science and Technology，Lanzhou University，a visual data analysis system using LabVIEW is developed．Based on the visual programming methods，the visual data analysis system can be used to carry out the efficiency and energy calibrations for HPGe detector，realize the experimental data analysis and processing and the visual output of experimental results．There are mainly two kinds of common functions，that is，activity measurement and judgement of unknown nuclide，in the system．The visual data analysis system is clear，simple and easy to operate，which can enrich the experiment teaching mode，stimulate students’interest in learning and improve the effect of experiment teaching． Moreover，the visual data analysis system is also useful for the neutron activation analysis，nuclide analysis and environmental radioactivity monitoring，etc．

Considering the character of the opt-electric profession of Henan University of Science and Technology，on the base of Former Soviet psychologist Vygotsky’s zone of proximal development theory，we introduced expanding computer simulation experiment into the traditional experimentcal teaching of electrostatic field simulation at different levels．Depending on the hierarchical teaching mode，the design with ideological and political education included the teaching objects，the teaching objectives，the contents of course，the teaching methods and the instructional evaluation．The hierarchical instructianal design gived full play to the students’initiative，improved their physical science literacy and practical ability，motivated their scientific spirit of thinking and exploring．The students’professional confidence was also improved．

The successive differential method and the least square method are used to process the experimental data of Young’s Modulus Measurement Based on Matlab．The Matlab GUI is used to design an interactive interface for data processing and the fitting diagram plotting．Moreover，the experimental results are analyzed by inputting the measured data and experimental paramete．The operation is simple，which can improve students’ ability to use software and the experimental efficiency．

Oscilloscopes are widely used in college physics experiment teaching． Compared with traditional analog oscilloscopes，digital oscilloscopes convert input analog signals into digital signals for display．It designs a new comprehensive experiment for human voice recognition using a digital oscilloscope．In the experiment，the piezoelectric ceramic sheet was attached to the tester’s throat near the vocal cords．After the vibration of the vocal cords was converted into electrical signals，a digital oscilloscope was used to analyze the tester’s sound characteristics．On this basis，a voice sample database containing multiple testers is established，and the voice recognition of a specific tester is realized by comparing the tester’s voice frequency．This experiment broadens the experimental teaching content of oscilloscope and achieves good teaching effect．

With the rapid development of Internet technology，the traditional university physics experiment teaching has been difficult to apply to the complex teaching scene in the new era．In view of the shortcomings of traditional college physics experiment teaching，this paper analyzes and compares the advantages and disadvantages of online and offline teaching modes．Through the combined use of online teaching resources，home physics experiment and virtual simulation platform，an online intelligent classroom of college physics experiment is constructed，and a new teaching reform strategy of college physics experiment is explored in order to improve the traditional experimental teaching mode． To promote the reform of experimental teaching in colleges and universities，improve students’physical thinking ability and independent experimental ability．

“SEFDS”teaching mode focuses on the training needs of“new engineering”talents，takes students as the center，pays attention to the participation of students in knowledge，the generation process and output of knowledge system，and pays attention to the cultivation and exercise of students’self-learning ability，innovation ability and application ability． It takes Ampere circuital theorem as an example to discuss the application of this teaching model in teaching practice．

In order to give full play to the role of modern physical experiments in cultivating students’ innovative practical ability，innovative design elements are integrated on the basis of traditional confirmatory experiments，and scientific research and teaching experiments are organically integrated，which can effectively cultivate students’independent innovative thinking ability and practice ability，and retain the effect of traditional experimental teaching，both for undergraduate teaching and for future students’career development．The innovative and designed experimental mode is described by taking the preparation of metal element doped bismuth telluride based thermoelectric materials by magnetron sputtering as an example．It combines vacuum coating，thermoelectric properties and X-ray diffraction experiments with three important modern physics experiment projects，focusing on cultivating students’abilities of independent learning，independent design and independent innovation to meet the needs of future society and national development．