The experiment in which diode volt-ampere characteristics are tested via a voltlammetry method is an appropriate teaching content for students in the transition from secondary edueation to higher education due toits simple cireuit ,convenient operation and understandable principle.ln this work , the influences of temperature and meter eonnections in the experiment are studied to help people understand the experimental prineiple as well as improve the teaching quality. lt is suggested that the current flowing through the diode should be limitedto reduce the experimental error introduced by temperature rise.The experimental error is much smaller when the ampere meter is connected outside the voltmeter-diode loop, After math ematieal trealments by introducing the internal resistances of the meters , the experimental results measured when the ampere meter is connec tecinside the voltmeter-diode loop are similar to those when the ampere meter is connected outside the voltmeter. diode loop.The analyses of the experimental results and the oretieal formula show that the ideal current-voltage relationship in positive biased PN junction is not suitable for practical diodes.

With the rapid development of China's electric power industry ,the renewable energy ,e.g.,wind andsolar energy,has rapidly   developed.However,the uneven spatial distribution and the supply instability greatlrestrict the development of new energy technologies. Focused on the development of gravity energy storage( CES) technologies ,it introduces four kinds of new grid-level gravity energy storage technologies emerging inthe world in recent years,including Gravity Power CES in USA,Ares Mountain GES in USA, Energy VaultCES in Swiss ,and Gravitricity CES in UK.Compared to the traditional electrochemical energy storage methodsuck kinds of CES technologies has the advantages of safety , large storage capacity and small impact on theenvironment.Also,they significantly reduce the dependence on geographical conditions and water resources.which are beyond the application of the traditional pumped hydro storage CES method.Thus , these new CESmethods have broad application prospects. According to the available researches, it also points out thedevelopment obstacles and technical problems of the new gravity energy storage technology ,which can providespecific guidance on the domestic development of GES technologies in China.

The metal linear expansion coefficient of metal is studied common physical quantities ,to make amore accurate measurement of metal linear expansion coefficient,it lights amplification principle merged intothe field of measuring metal linear expansion coeficient,using self-made experimental devices such as lighisource ,light screen, heating device, etc. According to the geometric relationship between the reflection angleformed by the light path belore and after heating and the spot position before and after the light screen moves.the small shape variable of the metal is calculated through the moving distance of the spot ,and then the linearexpansion coefficient of the metal is obtained. The linear expansion coefficient of metal is obtained bycalculating the tiny shape varable of metal through the moving distance of the light spot.The average value ofthe linear expansion coefficient of copper is studied ,and compared with the standard value ,the relative error is0.05% ,and the method is extended to the measurement of the linear expansion coefficient of aluminum andtitanium,the relative error is less than 0.90% ,indicating that the method can be used for the measurement ofthe linear expansion coefficient of common metals.

There have been many studies on the evaluation of the uncertainty of the focal length of convex lensand the methods to reduce the experimental error.lt focuses on how to correctly select the appropriate focallength and aperture diameter of convex lens to reduce the experimental error,puts forward the important factorcausing the experimental error-the relationship between the focal depth and the lens parameters , and studies theinfluence of paraxial light on the experimental error.The research results provide a new way to reduce theexperimental error,and further study the law of lens imaging.

We design an Android smartphone application software Physics+ which can verify Newton's secondlaw based on the app.This method directly measures the acceleration of the slider movement in traditionalexperiments through mobile phone App and external acceleration sensor,records the complete change processof the acceleration ,and analyzes the experimental error automatically. Compared with the traditional experimentto verify Newton's second law ,this method is simple ,cost-effective ,fast and accurate ,and solves the problemsof low accuracy and large error of the traditional experiment method.The use of Android smart phones inphysical experiment teaching can help students understand Newton’s Second Law more vividly, stimulatestudents’interest in leaing physics, and is expected to become a powerful tool for physical experimentexploration and teaching.

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．

It focuses on the common problems in current experimental teaching of Newton Ｒing，such as students’lack of theoretical understanding，neglect of formula correction and sloppy error analysis．Heuristic teaching process is discussed to closely link the experimental operation with formula derivation．Students could find errors in the measurement process by themselves．Under the guidance of a teacher，a comprehensive data handling is conducted to obtain a revised scheme for error correction．This clear teaching process is based on the doubt and correction of experimental data，so that students’ participation is greatly improved．The significance of successive differential method and normalization processing could be deeply understood，while the comprehension of error factors measurement correction and data processing is greatly deepened．

Physics experiment competition is an effective way to cultivate students’higher-order thinking and innovative ability．It used the lag sequence analysis method to analyze the learning behavior of the participants in the Excellence Cup College Physics Experiment Competition，compared and analyzed the results of the expert review，and constructed a competition-teaching combination learning behavior sequence suitable for innovatively designed physics experiment competitions．The research methods and strategies can help teachers to objectively understand the learning goals and learning behavior characteristics of participating students，thereby improving the pertinence and effectiveness of the guidance for students’innovative practical activities．

The output voltage of the force sensor is an important parameter to be measured in the experiment ofmeasuring liquid surface tension coefficient by pulled off method. lt is very important to understand theexperimental principle and improve the accuracy of the experimental measurement.lt focuses on the study of thestate of the ring and the liquid film ,the change of force and the change of voltage with the height of the liquidhilm carried out by the ring during the measurement process,based on the experimental principle of measuringliquid surface tension coefficient by traditional pulling method.Finally,the selection of voltage measurementpoint in the experiment is clarified, the theoretical analysis formula is modified and the experiment ayerification is carried out.The verification results show that when the sling is in the critical state , the sensoroutput voltage U, should be selected as the maximum value of the voltage reading,which is more consistentwith the experimental principle.Moreover,the quality of the liquid film can not be ignored and should beincluded in the theoretical analysis and calculation to get more accurate results.The research results canprovide analysis ideas and reference for the course teaching of this experiment.

With the development of Internet technology in China,online teaching mode has emerged,and the hybrid teaching mode combining online and offline gradually appears.In order to improve the teaching quality of liberal arts physics experiment course,this paper uses the Superstar platform , 0Q and wechat etc., combined with offline classroom teaching to explore the mixed online and offline teaching mode of liberal arts physics experiment.The practice shows that the mixed teaching enriches the teaching means, improves the teaching elfect and learning efficiency and provides an effective way for the reform of liberal arts physics experiment

teaching.