Three model essays on senior high school physics teaching plans

# lesson plan # introduction lesson plans can show teachers' thinking process of preparing lessons, show teachers' understanding and mastery of curriculum standards, teaching materials and students, and their ability to organize teaching activities by using relevant educational theories and teaching principles. The following content is ready for your reference!

Article 1: Elasticity

I. Teaching objectives 1, knowledge and skills objectives

(1) Know what elastic force is and the conditions for its generation (2) Use the spring dynamometer correctly (3) Know that the greater the deformation, the greater the elastic force.

2, process and method objectives

(1) Understand the structure of spring dynamometer through observation and experiment.

(2) Through the use of self-made spring dynamometer and spring dynamometer, master the use method of spring dynamometer.

3. Emotions, attitudes and value goals

Through the production and use of spring dynamometer, we can cultivate a rigorous scientific attitude and a good habit of loving hands and brains.

Second, the key points and difficulties

Key point: What is flexibility? Correct use of spring dynamometer.

Difficulties: measuring principle of spring dynamometer.

Third, teaching methods: exploratory experiment and comparison.

Teaching instruments: ruler, rubber band, plasticine, paper, spring dynamometer.

Teaching process of verbs (abbreviation of verb)

(1) elasticity

1, elasticity and plasticity

When students experiment, pay attention to what happens:

(1) Put both ends of a ruler on the book, gently press it to deform it, feel the touch, remove the pressure, and the ruler will return to its original state;

(2) Take a rubber band, stretch the rubber band and experience the feel. When you let go, the rubber band will return to its original length.

(3) Take a piece of plasticine, knead it with your hands and let go, and the plasticine will keep its deformed shape.

(4) Take a piece of paper, knead the paper into a ball and unfold it. This paper will not return to its original shape.

Ask students to communicate the phenomena observed in the experiment, and classify these experimental phenomena, explain what they are classified by, and ask them to give some similar examples. (Classification according to whether the object can be restored to its original state after being deformed by force)

Ruler, rubber band, etc. It will deform when stressed and return to its original state when it is not stressed. This property of an object is called elasticity; Plasticine, paper, etc. Can't automatically recover its original shape after deformation. This property of an object is called plasticity.

2. Elasticity

When we press the ruler and pull the rubber bands, we feel their powerful function, which is called elasticity in physics.

Elastic force is the force produced by elastic deformation of an object. Elastic force is also a very common force. And any object will produce elastic force as long as it is elastically deformed. In daily life, the pressure of the bracket and the tension of the rope are essentially elastic.

3. Elastic limit

The elasticity of the spring has a certain limit, beyond which it cannot be fully recovered. When using the spring, you must not exceed its elastic limit, otherwise it will damage the spring.

(2) Spring dynamometer

1, measuring principle

It is made according to the principle that the greater the spring tension, the longer the extension.

2. Let the students summarize the methods and precautions of using the spring dynamometer.

When using dynamometer, you should pay attention to the following points:

(1) The measured force should not be greater than the measuring limit of the dynamometer, so as not to damage the dynamometer.

(2) Before use, if the pointer of the dynamometer does not point to zero, the position of the pointer should be adjusted to make it point to zero.

(3) Clear dividing value: In the calibration of spring dynamometer, know how much N each big battery represents and how much N each small battery represents.

(4) Pull the hook several times to see if it is flexible.

5. Exploration: the production and use of spring dynamometer.

(4) Class summary: 1. What is flexibility? What is plasticity? What is elasticity?

2. Measuring principle of spring dynamometer

3, the use of spring dynamometer.

(5) Consolidation exercises:

1, table tennis will bounce immediately after landing. The force that makes table tennis move from bottom to top is caused by table tennis.

2. The greater the tension of the spring, the longer the spring. It has a premise that it is done according to this principle.

3, about the elastic narrative is correct ()

A, only objects such as springs and rubber bands can produce elastic force.

B, as long as the object is deformed, it will produce elastic force.

C, the elasticity of any object is limited, so the elasticity can't be infinite.

D, the size of the elastic force is only related to the deformation degree of the object.

4, which of the following forces does not belong to the elastic force ()

A, the pulling force of the rope on the heavy object B, the gravitational force C, the supporting force D of the ground against people, and the pushing force of people against the wall

5. At the same time, two students pull the hook and knob of the spring dynamometer at both sides with a force of 4.2N At this time, the indicator displayed by the spring dynamometer is.

(6) Transfer:

Six, after-school reflection:

1, success:

2. Disadvantages:

3. Improvement measures:

Attachment: blackboard design:

First, flexibility:

1, elasticity and plasticity

2. Elasticity: the force generated by elastic deformation of an object.

3. Elastic limit

Second, the spring dynamometer:

1, measuring principle: the greater the tension on the spring, the longer the extension of the spring.

2. Usage: (1) Identify measuring range and dividing value.

(2) Check whether the pointer points to zero.

Chapter 2: Uniform Circular Motion

First, the analysis of teaching tasks

Uniform circular motion is the first curve motion to be learned after linear motion. It is how to describe and study the extension of motion that is more complicated than linear motion, is the further extension of the knowledge of the relationship between force and motion, and is the basis for learning other more complicated curvilinear motions (flat throwing motion, simple pendulum simple harmonic motion, etc.). ) in the future.

Learning uniform circular motion needs to be based on uniform linear motion, Newton's law of motion and other knowledge.

Starting with observing the phenomena in life and experiments, students can understand the conditions for objects to move in a curve, draw the conclusion that uniform circular motion is the most basic and simple circular motion, and experience the scientific research method of establishing an ideal model.

By setting the situation, students can feel the different speeds of circular motion, and realize the need to introduce physical quantities to describe the speed of circular motion, and then learn the concepts of linear velocity and angular velocity by analogy with uniform linear motion and multimedia animation.

Through group discussion, experimental inquiry and mutual communication, a platform is created for students to discuss and analyze several practical problems according to the knowledge learned in this class, so as to mobilize students' learning emotions, learn to cooperate and communicate, and cultivate rigorous and pragmatic scientific quality.

Through life examples, we know that circular motion is everywhere in life, and it is very necessary and important to study and study circular motion, which can stimulate learning enthusiasm and interest.

Second, the teaching objectives

1, knowledge and skills

(1) Know the conditions under which an object moves on a curve.

(2) Understanding circular motion; Understand uniform circular motion.

(3) Understand the linear velocity and angular velocity.

(4) Calculate the linear velocity and angular velocity in practical problems and judge the direction of linear velocity.

2. Process and method

(1) Through the formation of the concept of uniform circular motion, we know the physical method of establishing an ideal model.

(2) Understand the application of analogy by learning the definitions of uniform circular motion, linear velocity and angular velocity.

3. Attitudes, emotions and values

(1) Understand the universality of circular motion and the necessity of learning circular motion from life examples, and stimulate learning interest and curiosity.

(2) Through the learning process of discussing and communicating with each other, I understand the important role of cooperation and communication in learning. I am willing to cooperate with others in activities, respect the opinions of my classmates and be good at communicating with others.

Third, the focus and difficulties in teaching

Key points:

The concept of (1) uniform circular motion.

(2) Linear velocity and angular velocity are used to describe the speed of circular motion.

Difficulties: Understand that the linear velocity direction is the tangent direction of each point on the arc.

Fourth, teaching resources.

1. Equipment: wall clock, pull-back toy trolley, turntable with holes on the side, glass plate, yellow sand for building, table tennis, inclined plane, scale, and small balls connected with strings.

2. Courseware: flash courseware-demonstrating uniform circular motion with different arc lengths at the same time; —— Demonstrate uniform circular motion with two motion radii rotating at different angles at the same time.

3. Video: The process of the three-ring roller coaster.

Five, teaching design ideas

This design includes three parts: the conditions for the object to do curvilinear motion, uniform circular motion, linear velocity and angular velocity.

The basic idea of this design is: on the basis of video and experiment, the conditions for the object to move in a curve are obtained through analysis; Through observation and comparison, the characteristics of uniform circumference are summarized. Based on the different descriptions of uniform circular motion speed by situational awakening, the concepts of linear velocity and angular velocity are introduced through discussion, questioning, activity and communication, so as to consolidate the learned knowledge and solve practical problems by using the learned knowledge.

The key points of this design are: the concept of uniform circular motion and the concepts of linear velocity and angular velocity. The method is as follows: by observing and comparing the two circular motions of clock hands and roller coaster, the characteristics of uniform circular motion are summarized; Set the dialogue scene between the earth and the moon, and introduce the description of uniform circular motion speed; Then, with the help of multimedia animation, the concepts of uniform circular motion, linear velocity and angular velocity are obtained by analogy with uniform linear motion.

The difficulty of this design is: the direction of linear velocity. The method is: two demonstration experiments, observing the ball flying in a circular motion along the tangent line and the trajectory distribution of red ink flying on paper from the edge of the rotating turntable, are displayed intuitively.

This design emphasizes taking video, experiment and animation as clues, focusing on stimulating students' senses, emphasizing students' experience and feelings, transforming abstract thinking into image thinking, teaching concepts and laws embody physical methods such as "modeling" and "analogy", and students' activities focus on discussion, communication and experimental exploration, and the issues involved are linked to real life, close to students' life, emphasizing the perception of learning value and significance.

It takes about 2 class hours to complete the design.

Sixth, the teaching process.

1, teaching flow chart

2, flow chart description

Scene 1 Video, Presentation, Question 1

Play the video: Three-ring roller coaster, let students see that the movement of objects has straight lines and curves.

Demonstration: Let the students blow hard on the table tennis ball that moves in a straight line and experience the situation under which the ball will move in a curve.

Question 1: Under what circumstances will an object move in a curve?

Situation 2 Observation, Comparison and Questioning 2

Observe and compare two kinds of circular motion: clock hands and roller coaster.

Question 2: What is the difference between the above two circular motions? What are the characteristics of the circular motion of clock hands? Establish the concept of uniform circular motion.

Scene 3 demonstration, animation

Situation: The speed battle between the moon and the earth.

Multimedia animation: demonstrate that two movements with different arc lengths do uniform circular motion at the same time, and get the linear velocity table by comparison.

expression

Demonstration 1: The ball bound with rope moves circularly in the horizontal plane, and suddenly one end of the rope is released, and the ball moves along the tangent direction of the arc.

Demonstration 2: Demonstrate the trajectory distribution of red ink flying from the edge of the rotating turntable on the paper by physical projection, and show the direction of linear velocity.

Situation: Change the shift of the electric fan in the classroom, see the different rotational speeds of circular motion, and introduce the concept of angular velocity.

Multi-media animation: demonstrate that two different angles of motion radius do uniform circular motion at the same time, and compare them to get the angular velocity expression.

Activity discussion, experiment, exchange and summary.

Identification: Please tell me what circular motions in life can be regarded as uniform circular motions? Understand students' understanding of uniform circular motion and whether they have modeling ability.

Observation and analysis: What is the relationship between the linear velocities of each point on the edge of two shafts in transmission equipment such as magnetic tape, correction belt and bicycle chain? Understand the concept of linear velocity.

Calculation: Calculate the multiple relationship between the linear velocity and angular velocity of the needle tip of the hour hand, minute hand and second hand of the wall clock. Understand whether useful data can be obtained through actual measurement, and flexibly use linear velocity formula and angular velocity formula to solve practical problems.

Small experiment: provide pull-back toy car, glass plate and yellow sand for building. Through experimental observation, it is explained where the fender of automobile wheel should be installed, so as to understand the direction of linear speed.

Interpretation: judging the dispute between the earth and the moon.

Summary of slides.

3. Main teaching links This design can be divided into four main teaching links:

In the first part, by playing videos and demonstrations, the conditions for objects to move in curves are summarized.

In the second part, through observation and comparison, the ideal model is established, the characteristics of uniform circular motion are summarized, and the concept of uniform circular motion is obtained by analogy with uniform linear motion.

Thirdly, through scene awakening, the circular motion is described by linear velocity and angular velocity, and the definitions and formulas of linear velocity and angular velocity are obtained by analogy with uniform linear motion with the help of multimedia animation.

The fourth link, centered on student activities, discusses, explores and exchanges several practical problems to deepen the understanding and application of the knowledge in this lesson.

Seven. Example of teaching plan

The first link: the condition of the object moving on the curve.

[Create a scene] Play a video: the action of the three-ring roller coaster in the forest park.

[Question] 1. Please tell me what different kinds of sports the roller coaster did. (uniform linear motion, uniform acceleration linear motion, uniform deceleration linear motion, curvilinear motion, circular motion, etc.). )

2. Under what conditions will an object move in a curve?

[Demonstration] Let the table tennis roll down from the inclined plane to the horizontal table for linear motion. Ask a classmate to blow the ball hard in the direction inconsistent with the ball movement and observe the change of the ball movement track.

【 Conclusion 】 When the resultant force of the object and the velocity direction are not in a straight line, the object moves in a curve.

[Introduction] Curved motion with a circular trajectory is called circular motion. Let's learn how to study curvilinear motion from circular motion.

The concept of uniform circular motion in the second link

[Observation and discussion] What are the characteristics of the circular motion of the hour hand, minute hand and second hand of a clock? How are they different from the circular motion of roller coasters?

The circular motion of the hour hand, minute hand and second hand of a clock is characterized by uniform rotation, while the speed of a roller coaster is constantly changing. )

[Question] How to define uniform circular motion? (Guide students to define uniform circular motion by analogy with uniform linear motion)

【 Conclusion 】 The circular motion of particles with the same arc length at any time is called uniform circular motion.

Uniform circular motion is the most basic and simple circular motion and an idealized physical model.

[Introduction] How do we study circular motion?

The concepts of linear velocity and angular velocity in the third link

[Creating Scenes] The Speed Debate between the Earth and the Moon

Earth: I walked around the sun for 29.79 km 1 sec, and you walked around me 1.02 km 1 sec. You are too slow!

Moon: You only do it once a year, and I do it once every 28 days. You are too slow!

[Question] How to define the physical quantity describing the circular motion speed? Multimedia animation: demonstrate uniform circular motion with different arc lengths at the same time;

【 Conclusion 】 Definition of linear velocity: The ratio of the arc length S through which a particle passes to the time t used is called the linear velocity of circular motion.

Formula: unit: m/s (m/s)

[Question] Speed is a vector. What is the linear velocity direction of circular motion?

[demonstration] 1. Use a small ball with a thin thread at one end, put one end of the thread on a nail, and the nail stands vertically on the table. Give the ball initial speed to make the ball move in a circle on the horizontal table, suddenly pull out the nail and see the ball move in the tangential direction of the circle;

2. Observe the red ink flying from the edge of the rotating disk and the track distribution on the paper through the projector;

【 Conclusion 】 Linear velocity direction: along the tangent direction of the arc.

Linear speed represents the instantaneous speed of circular motion and is a vector; The linear velocity direction of circular motion is constantly changing, so uniform circular motion is variable speed motion, and "uniform velocity" in uniform circular motion is "uniform velocity".

Situation: Turn on the electric fan in the classroom, change gears and observe its speed. Guide students to understand that the physical quantity describing the rotational speed of circular motion is different from the linear speed. )

Chapter 3: Free Fall Motion

First of all, free fall.

1. Definition: the motion of an object falling from a static state only under the action of gravity.

Thinking: Are different objects falling at the same speed? Why do objects fall differently in vacuum than in air?

The difference between air and vacuum is that there is air resistance in air. For some low-density objects, such as parachutes, feathers, paper, etc. When they fall in the air, they are greatly influenced by air resistance. However, some dense objects, such as metal balls, have relatively little influence on air resistance when falling, so the speed is different when falling in the air.

In a vacuum, all objects are only affected by gravity and fall freely at the same speed.

2. The relationship between the falling speed of different objects and gravity.

(1) When there is air resistance, due to the influence of air resistance, different weights fall at different speeds, and often heavier objects fall faster.

(2) If objects are not affected by air resistance, although different objects have different masses and shapes, they fall at the same speed.

3. The characteristics of free fall

( 1)v0=0

(2) Constant acceleration (a=g).

4. Nature of free falling body: uniformly accelerated linear motion with zero initial velocity.

Second, the acceleration of free fall.

1. The acceleration of a free fall, also known as the acceleration of gravity, is usually expressed by g. 。

2. The acceleration direction of free falling body is always vertical downward.

3. In the same place, all objects have the same acceleration of free fall.

4. The acceleration of free fall in different geographical locations is generally different.

Law: the gravity acceleration of the object on the equator is the smallest, and the gravity acceleration of the south (north) pole is the largest; The greater the latitude of an object's geographical position, the greater the acceleration of gravity.

Third, the motion law of free falling body

Since the free-fall motion is a uniformly accelerated linear motion with an initial velocity of 0, the basic formula and inference of the uniformly variable linear motion are applicable to the free-fall motion.

1. Speed formula: v=gt

2. Displacement formula: h= gt2

3. Displacement velocity relation: v2=2gh

4. Average speed formula: =

5. Inference: δ h = GT2

● Questions and inquiries

Question 1 Is it the same for an object to fall in vacuum as it does in air? What are your assumptions and guesses?

Thinking: When an object falls in a vacuum, it is only affected by gravity and is no longer affected by air resistance. At this time, the acceleration of the object is large, and the whole falling process is accelerated. In air, objects are not only affected by gravity, but also by air resistance, and in the opposite direction. At this time, the acceleration of the object is small, and the whole falling process is slow.

Question 2: Free fall is an idealized model. Please talk about under what circumstances can the falling motion of an object be regarded as a free fall?

Thinking of inquiry: Reviewing the concept of particle In the first chapter, we talked about how to grasp the main factors in the problem, ignore the secondary factors, establish an idealized model, simplify complex problems and further understand this important scientific research method according to the nature and needs of the research problem.

Question 3: Is the acceleration of a free-falling object the same in different parts of the earth?

Exploring ideas: In different places on the earth, the same object is subjected to different gravity, resulting in different acceleration of gravity. Generally speaking, the closer to the poles, the greater the acceleration of the free fall of an object; The closer to the equator, the smaller the acceleration.

● Classic topics and detailed analysis

Example 1 The following statement is incorrect.

A. an object falling from a static state must do free fall.

B. If the air resistance can't be ignored, it must be the rapid falling of heavy objects.

C. the acceleration direction of free fall is always vertical downward.

D a falling motion whose speed is proportional to time must be a free falling motion.

Detailed analysis: This topic mainly examines the understanding of the concept of free fall. Free-falling motion refers to the motion that an object falls from a static state only under the action of gravity. Option A does not specify what kind of object it is, and it is unknown whether the air resistance it receives can be ignored. In option C, the acceleration direction of free fall should be vertical downward, and the speed of uniform acceleration linear motion with zero initial velocity is proportional to time, but it is not necessarily free fall motion.

Answer: ABCD

Example 2 After a heavy rain, Xiao Ming observed the water drops dripping from the roof of his house, and found that the time for each drop to fall was basically 1.5 s, thus estimating the approximate height of his house and the instantaneous speed of the water drops before landing. Do you know how Xiao Ming estimated it?

Fine analysis: Roughly estimated, water droplets are regarded as free falling bodies, and g is 10 m/s2, which can be obtained from the law of falling bodies.

Answer: Let the speed of the water drop when it falls to the ground be vt and the height of the house be h, then:

Vt = gt =10×1.5m/s =15m/s.

h = gt2 =× 10× 1.52m = 1 1.25m。

Green channel: Learning physics theory is to guide practice, so we should pay attention to integrating theory with practice in learning. The analysis of problems should proceed from reality, and whether various factors affect the results should be analyzed in detail.

Example 3 If a free-falling body falls 25 m at the last 1 s, how high is the free-falling body? (g =10m/s2)

Detailed analysis: in this question, the object is in free fall, the acceleration is g= 10 N/kg, and the final displacement of the object 1 s is 25 m. If the whole time of the object is assumed to be t and the whole displacement is s, the displacement of the object at the first t- 1 s is s-25 m, which is given by the equation H = gtt.

Answer: If an object falls from H and the elapsed time is t, then there are:

h= gt2 ①

h-25= g(t- 1)2 ②

According to ① ②, h=45 m, t = 3 s.

Therefore, the object falls from a height of 45 m above the ground.

Green channel: divide the free-falling process of an object into two sections, find the equivalence relationship, and solve the equations simultaneously by using the law of free-falling respectively.

Autonomous square

● Meet basic standards.

1. Let two stones, one light and one heavy, fall freely from the same height, while ignoring the air resistance, then

A at any time before landing, the speed, displacement and acceleration of two stones are the same.

B. Heavy stones fall fast, while light stones fall slowly.

C. the average speed of two stones falling is equal.

D The ratio of their falling heights at 1 s, 2 s and 3 s is 1: 3: 5.

Answer: ACD

2. If two balls A and B fall freely from the same height with a distance of 1 s, they are in the process of falling.

A. the speed difference between two balls is always the same. B. the speed difference between the two balls is getting bigger and bigger.

C. the distance between two balls is always the same. The distance between the two balls is getting bigger and bigger.

Answer: AD

3. When an object falls freely from a certain height, the ratio of its landing speed to its half-height speed is

A.2 B. ∶ 1

C.2∶ 1 D.4∶ 1

Answer: b

4. Release two heavy objects continuously from the same height. After A is released for a period of time, B is released with B as the frame of reference. The movement form of A is

A. free fall B. uniformly accelerated linear motion A.

C. Uniform Accelerated Linear Motion a> Uniform Linear Motion

Answer: d

5. The mass of object A is five times that of object B, and A falls freely from the height of h, while B falls freely from the height of 2h at the same time. Before landing, the following statement is correct.

A. At the end of falling 1 s, their speed is the same.

B When they fall 1 m respectively, their speed is the same.

The acceleration of C.A is greater than that of B.

D. At the same time, in the process of falling, the speed of A is greater than that of B.

Answer: AB

6. If a small ball falls freely from a height of 80 m above the ground, if g= 10 m/s2, find the displacement in the last 1 s before the ball hits the ground.

Answer: 35 meters

● Overall development

7. Two objects are connected by a rope with a length of L=9.8 m and fall freely from the same height with a time difference of1s. When the rope is tightened, how long does it take for the second object to fall?

Answer: 0.5 s

8. A ball falls freely from the eaves and passes through a window with a height of Δ δh = 2m within Δ δt = 0.2s How high is the top of the window from the eaves? (take g g= 10/0m/s2)

Answer: 2.28 meters

9. As shown in Figure 2-4- 1, a pole with a length of 15 m is vertically hung, and there is an observation point A at a distance of 5 m from the lower end of the pole. When the rod falls freely, try to find the time required for the rod to pass through point A from the lower end.

(g =10m/s2)