Research On The Law Of Double-bar Model And Exercise Teaching In Senior High School Physics

In 2017,momentum related knowledge has been included in the required content of the college entrance examination,which has injected new vitality into the proposition of combining kinematics and mechanics.The problem of double conductor rods cutting magnetic induction lines in guide rails（hereinafter referred to as the double rod problem）has become a hot topic in the college entrance examination proposition.From the perspective of the characteristics of the double rod problem itself,such problems are difficult and require high ability of students,so students often lose points because of improper grasp of the law when analyzing such problems;from the perspective of the existing research on the double-stick problem,there is not much research on such problems,and there is a lack of in-depth analysis of the law of the double-stick problem and its exercise teaching.Therefore,this study takes the “ double-stick model ” as the clue,the “ exercise teaching ” as the realization path,and the “ law of the double-stick model ” as the content carrier.It focuses on the following three questions : first,what are the characteristics of the double-stick problem in college entrance examination questions,second,what are the laws of the double-stick model,and finally,how to carry out the exercise teaching of the double-stick model.Aiming at the first problem,based on the college entrance examination ability requirements and core literacy level,this paper analyzes the double-rod problem in college entrance examination in recent years,and finds that the double-rod problem has the following characteristics : Firstly,the double-rod problem has a wide range of contents and spans.Propositioners can examine students ’ mastery of corresponding knowledge from multiple perspectives such as movement,force,circuit,momentum and energy.Secondly,the process analysis of the double-rod problem is complex.In the double-rod problem,the velocity relationship of the two metal rods affects the induction electromotive force of the whole circuit and the magnitude and direction of the ampere force of the double rods,which leads to the different dynamic characteristics of the double rods and makes the dynamic analysis of the double-rod problem extremely complex.Thirdly,the double-stick problem has high requirements for students ’ thinking ability.In the complex double-stick situation,it has high requirements for students ’ scientific thinking ability such as reasoning,questioning and criticism,and model construction.For the second problem,based on the “ double-rod + guideway ” structure（hereinafter referred to as the double-rod model）in the situation of double-rod problem,two basic doublerod models with constant force and initial velocity are constructed by using the idea of modeling.By constructing the motion differential equation for solving the double-rod model,the law of the double-rod model is visually explored by using the idea of combining number and shape.In addition,this paper also expands the two types of basic double-stick models in three ways,analyzes the law of the expanded model,and compares the similarities and differences in the law with the basic model to help teachers and students understand the law of the double-stick model more comprehensively.The research results have clear directional characteristics: Correct understanding of the variation law of the motion and circuit characteristics of the double-rod model is the basis for solving the problem,and correctly grasping the characteristics of the stable state of the motion and circuit is the key to solving the problem.Therefore,when we analyze the law of the model,we focus on and analyze the variation of the motion and circuit characteristics of the basic model and the extended model,and determine the stable state characteristics respectively.In order to solve the third problem,we deeply analyze the problem-solving thinking on the basis of the study of the law of the double rod model.The commonly used scientific thinking methods are : conservation thinking,analogy thinking,equivalent thinking,holistic and isolated thinking,modeling thinking;in order to assist the exercise teaching,the corresponding exercise teaching strategies are put forward : the selection of exercise strategy,the image teaching strategy,the problem chain teaching strategy,and the one-to-three teaching strategy.Combined with problem-solving thinking and teaching strategies,a double-rod model exercise teaching is designed to cultivate students ’ problem-solving thinking and the ability to flexibly use physical knowledge and methods to solve practical physical problems,so as to realize the transformation from "problem-solving" to "bring an issue to a close".