Reflection on acceleration teaching

Part 1: Reflection on Acceleration Teaching

The concept of acceleration, for the middle school students who have just stepped into the high school threshold, is too abstract! First of all, in daily life, in most cases, students only involve how many distances, displacements, and movements. Rarely encounters the phenomenon that speed changes are fast and slow. It can be said that physics is not studied, and the concept of "acceleration" is not spontaneously formed in the mind. Secondly, students' abstract thinking ability is not high, and changes in speed and speed are The difference in the rate of change of speed is difficult to distinguish; finally, in the teaching process, students often only focus on results, light processes, and then through a large number of exercises to remember the conclusions, if so, students' thinking ability will not be cultivated. In addition, acceleration is a bridge between dynamics and kinematics, mechanical vibration, electromagnetic field, energy conservation, momentum theorem, etc. are all involved. It is impossible to explain it through a class of time, so that students can automatically accept and use it psychologically. This is a gradual process. Therefore, teachers should fully excavate the materials of books, such as images, tables, and data. When doing their best, collect the phenomena related to the speed of change, and cause students to pay attention to the concept of acceleration; use demos, analogies, metaphors, etc. to help Students understand the meaning of acceleration; mobilize students to participate in the teaching process, cultivate students' thinking ability, and mobilize the interest in learning physics.

Part 2: Reflection on Acceleration Teaching

In the previous lesson, I learned the concept of speed. Students learned how to use the ratio method to describe the motion of an object. It allows students to review the process of drawing out the speed concept and use the analogy method to migrate to the concept of acceleration. This gives learning acceleration. A concept lowered the steps. However, because students' abstract thinking ability is not strong, the difference between speed and speed change and speed change is difficult to distinguish; in the student's life experience, there are not many phenomena related to acceleration, which makes students form and understand acceleration. The concept of science brings difficulty.
Teachers create physical situations that allow students to discover and experience after observation and experience. They use scientific thinking to germination and refine scientific problems, making the teaching process a process of discovering problems, asking questions, analyzing problems and solving problems. Let the students use the method of inquiry to “walk” the establishment process of the acceleration concept, and explore the order from simple to complex, from special to general. It is logical to introduce the concept of acceleration. Then, from the two aspects of formula and image, through the analysis and comparison of the concept of acceleration and speed in life, to deepen the understanding of the physical meaning of acceleration, the design process of this class teaching is: subjective feelings of students - asking questions - divergence analogy - expanding inquiry - Communication and cooperation - analysis and argumentation.
After introducing the concept of acceleration, the actual application of acceleration is experienced through an interesting example. The specific data table shows that the uniform linear motion is the motion with constant acceleration. Due to the importance and relevance of speed and acceleration, students should be guided to compare and analyze the changes in speed and speed, in order to have a deeper understanding of them. You can use the way of class discussion to emphasize two problems to the students: First, the physical meaning of speed, speed change and acceleration is completely different, and the acceleration with large speed change is not necessarily large, but also depends on the change. Secondly, the magnitude of the acceleration does not have any direct relationship with the magnitude of the speed. The acceleration of the car at a high speed on the highway has zero acceleration. Temporarily avoid several problems: First, only propose that the acceleration is a vector, how to judge the direction should be temporarily avoided, pay attention to gradual progress, do not require too high understanding, to be introduced to Newton's second law and then study; second, should not mention "speed The speed of change, including "the speed of change in speed direction."

Chapter 3: Reflection on Acceleration Teaching

The concept of acceleration is both important and difficult. First of all, pay attention to the introduction of acceleration. It can be started by bus and trolleybus, and the speed is accelerated from zero to 5m/s, which makes students realize how fast the speed changes. It can also be demonstrated that the object slides down from the slope of different inclinations, and the distance of sliding on the horizontal plane is about the same. What is the difference in the speed change of the inclined surface of the object at different inclination angles? Therefore, it is proposed that the speed change is fast and slow. After introducing the concept of acceleration, two issues must be emphasized. First, the acceleration does not indicate an increase in speed, nor a change in speed, but the speed at which the speed changes. Second, the magnitude of the acceleration does not have any direct relationship with the magnitude of the speed. The acceleration of the car at a high speed on the highway has zero acceleration. Both of these issues can be discussed in a classroom discussion.
Temporarily avoid a few questions:
First, only the acceleration is a vector. How to judge the direction should be avoided temporarily, and the second law of Newton should be extracted and studied.
Second, it is not appropriate to mention "the speed of speed change", including "the speed of the speed direction change";
Third, it is not advisable to mention the average acceleration and the instantaneous acceleration.
In the teaching process, you may wish to give more examples, which will help students understand the concept of "acceleration". For example, we can give students an example of a car that increases its speed from 0km/h to 108km/h in 10s. If it is uniform acceleration, the acceleration is 3m/s2. When the car encounters special circumstances, Starting from 108km/s and stopping at 4s, the acceleration at this time is 7.5m/s2.
The above car is in the acceleration phase, the acceleration is 3m/s2, then the first second is 3m/s, the second second is 6m/s, the third second is 9m/s... The tenth second is 30m/ s, is 108km / h. In the braking phase, the acceleration is 7.5m/s2, starting from 30m/s, the brake reaches 22.5m/s in the first second, 15m/s in the second second, and 7.5m/s in the third second, the fourth second. At the end, reach 0 and stop.
The examples should be easy to understand, and then you can give a few more. If you let the students give each other a group of examples, the effect is the best.

Part 4: Reflection on Acceleration Teaching

Acceleration is an important concept in mechanics. It is a bridge between dynamics and kinematics. The focus of this lesson is on the concept of acceleration and its physical meaning. The difficulty is the difference between acceleration and speed. Acceleration is the physical quantity defined by the ratio definition method. The textbook starts from the definition of acceleration, proposes the concept of change rate, and correctly understands the meaning of change rate. It is very important for learning and correctly understanding other physical quantities defined by ratio.
The relationship between acceleration and real life is relatively close. In addition to the concept of the face of acceleration introduced from the comparison of many practical examples, the textbook introduces the familiar speed of linear motion in the life of cars, trams, airplanes, skydiving and other life. The actual value, and in the exercise infiltrated experimental data reflecting the acceleration performance of the car. In this lesson, we should start from the familiar phenomenon of students, interact with teachers and students, discuss and study in depth, and deepen the knowledge points of this section to promote the cultivation of students' practical ability.
Reasonable and ingenious design of vivid classroom teaching to capture and drive every student, to achieve the goal of new curriculum reform to the maximum extent, to perfectly reflect the spirit of the new curriculum reform. Let me talk about the establishment of the concept of acceleration:
First, the teaching mode - cooperation, problem teaching mode
Creating problems - students' existing cognition - students process and reorganize problems at the existing level of knowledge - form new cognitive structures - integrate and strengthen to form new concepts.
Second, the process design
1. The problem of the speed variation of the problem 1 is created according to the student's cognitive stratification; if the moving speed of the object on a straight plane is increased by 18 M/S from 5 M/S. 2 The problem of setting the speed change number in the coordinate axis.
2. The students analyze and deal with the problem and clarify: the relationship between the speed of the object movement, the speed of the object change, and the number of speed changes.
3. Organizational strengthening forms a new introduction.
Third, the teaching should pay attention to the principle of starting from a simple and step by step. Use students' cognitive conflicts to activate student thinking and promote learning transfer to mobilize students' polarity.
Regarding the direction of acceleration, there is a limitation in the range of linear motion in the shifting motion. The definition of the acceleration is used, and the direction of the initial velocity is defined as the positive direction. When the acceleration is not greater than the initial velocity, the acceleration calculated by the formula is positive. Therefore, the acceleration direction of the acceleration motion is the same as the initial velocity direction; the deceleration motion is also the same. This method is more suitable for our students, making it easy for students to understand and master.
For the vt image, the students are discussed from the inclination of the linear motion, and then the students are led to the correct conclusion.

Part V: Reflection on Acceleration Teaching

I believe that the cognition from the speed of movement to the speed of speed change is a leap in the cognitive level of students. In order to help students embark on this cognitive step, students are presented with a different set of data for five examples, so that students have a preliminary understanding.
Student-led, let students define concepts themselves. In the process of defining the acceleration, through the discussion and communication of the students, the students are guided to use the ratio of Δv/Δt to describe the speed of the speed change, and the acceleration is regarded as a symbol of the ratio. “Acceleration” is just the name of a symbol. However, the purpose of embodying the abstract concept and visualizing the blunt concept is realized. The students regard acceleration as a new understanding of friends, and they have a sense of intimacy. They have experienced the whole process of defining the concept of acceleration, and the understanding of the concept is even more profound. But the feeling of teaching has yet to be improved.
This lesson consciously carries out the method of controlling the variable method and the method of defining the physical quantity with the ratio. The education of the control variable method is carried out in a subtle way. For the method of defining the physical quantity by the ratio, not only the student is indicated that the ratio is used to define the acceleration, and Together with the students, we reviewed the definition of the average speed and the definition of physical quantities such as pressure, density, and resistance in the middle school. The purpose is to let students understand that many physical quantities are defined for the convenience of research or description, so that students can eliminate the mystery and fear of physical quantity and thus produce intimacy.
The difficulty of teaching in this lesson is the difference between acceleration direction and acceleration and speed. The teaching of acceleration direction is to let students discuss the vectority of acceleration according to the vectority of displacement and speed. It is necessary to further select more effective teaching methods. try.