Rockets are inspired by balloons.

Hawkeye missile system is designed according to the structure of Hawkeye.

Here are some scientific introductions:

"Structure and Design" starts with the understanding of common structures, discusses the basic classification of forces and structures in the technical field of vision through examples familiar to students, and strengthens the understanding of different types of structural characteristics through interesting experiments. It is the basis of learning in this unit and the key content of cultivating interest.

This content is to let students "understand the meaning of structure, understand the concept and general classification of structure from the perspective of mechanics", and at the same time "combine 1 ∽ two simple structural cases to analyze how the structure is stressed"

2. The focus of teaching materials

(1) Structure and force.

(2) Structure type.

Second, the analysis of teaching objects

Due to the accumulation of life experience, students have a certain understanding of structure and a certain foundation for the function and classification of structure. In addition, students have learned about mechanics in physics class, which has a good foundation for force analysis of objects. However, because force analysis is a difficult point in physics teaching, it is still a difficult point for most students to analyze the force on objects. Therefore, it is difficult for students to understand the structure from the perspective of mechanics, which makes the stress analysis and stress concept of simple structures become the difficulties in this teaching.

Third, the teaching objectives

1. Understand the meaning of the structure.

2. Be able to understand the concept and general classification of structures from the perspective of mechanics.

3. Can combine 1 ∽ two simple structural cases to analyze how the structure can withstand.

Fourth, teaching strategies.

1. Understand the concept of structure from the mechanical point of view by applying "Constructivism Learning Theory".

2. Experience observation, thinking and analysis, and feel the classification and stress characteristics of the structure.

3. Let the students personally carry out the "cardboard bearing test", observe the teacher's "egg bearing" demonstration test, and feel the stress characteristics of different types of structures.

4. Let students make entities with different structural types with simple materials, and strengthen their understanding of the stress of different types of structures.

5. Teaching time: 2 hours.

Preparation of teaching resources for verbs (abbreviation of verb)

1. Prepare some pictures.

2. Equipment 1: 3 raw eggs of the same size, 6 mineral water bottle caps, one board and three bricks.

Equipment 2: thin bamboo sticks, toothpicks, plasticine, eggshells, glue, Gaobao granules, etc.

Six, teaching program design

No. Teaching Content Teachers Guide Students' Activities

1 Introduce this chapter.

Design teaching situation: ppt shows some pictures of "wonderful structural phenomena" and asks the following questions:

(1) Acrobatics Why can people stand on eggs? (2) Why does the leaning tower of Pisa tilt but not fall? (3) Why did the dinosaur's back arch upward? Appreciate and think

2 the concept of structure

1. Guide students to analyze the similarities and differences of all the structures in the diagram.

2. Play concept: structure refers to the orderly collocation and arrangement between the components of things. Analyze and summarize the existing pre-concepts

3 case study:

"Xanthium sibiricum and Velcro", "Birds and Planes" and "Hawkeye and Missile Tracking System" (Annex I)

Revelation: (1) Why do humans study structure?

(2) How do people solve problems?

From three examples in the case, we can understand the purpose of human research on structure, and how to get inspiration from various structures existing in natural animals and plants, and realize some inventions and creations, so as to serve mankind.

4 act immediately

Guide students to think about "which product structure is inspired by the structure of natural things in production and life?" Students use their existing knowledge and experience to think and discuss.

5 deepen the concept of structure

(1) Guide students to understand the concept of structure from a mechanical point of view: structure refers to a building form that can withstand certain forces, and it can resist forces that can cause changes in shape and size.

Key point: the structure is to bear and resist deformation, which is the essence of the structure.

(2) Explain the concepts of internal force and stress with tug of war.

(3) Demonstrate five basic stress forms of members: tension, compression, shear, torsion and bending. (Annex III)

(4) Analyze the stress on the chair surface, and strengthen the concept of structure again: under the combined action of various forces, the chair surface will generate internal force to resist external force, and when the internal force exceeds a certain value, the chair surface will break. Deployment: One of the tasks of structural mechanics is to find out where the internal force of the structure is the largest under the action of external force.

Question: Where is the maximum internal force of the rope during tug-of-war? Please answer this question according to your own life experience. Listen, record, think and answer the teacher's questions.

6 act immediately

The stress of crane bracket, cable-stayed bridge, supporting beams at both ends and dam is analyzed. Discuss and answer.

7 small experiments

Objective: To compare the pressures of different shapes of cardboard. (Annex II)

(1) Organize students to do the experiment in pairs.

(2) After students finish the experiment, guide them to summarize the test results.

(3) According to the test conclusion, the stress of arch bridge is analyzed.

(1) Hands-on test and summary.

(2) Stress analysis of arch bridge.

8 kinds of structures

(1) Through the pictures and some objects displayed before the new class teaching, teachers and students jointly summed up three basic structural types: three-dimensional structure, frame structure and shell structure.

(3) Explain the stress characteristics of these three structural types. Listen to the class and participate in the discussion.

9 quiz:

Test purpose: To understand the stress of shell structure.

Note: Three raw eggs of the same size, six suitable bottle caps, 1 pine nuts, and three bricks.

Test process: put three bottle caps on the table in a triangle shape, stand the eggs on the bottle caps respectively, and then cover the other three bottle caps on the eggs. Take a board and put it on it. Gently press the brick on the board.

Test record: record the number of bricks that an egg can bear. The teacher demonstrates and guides the students to discuss the following questions:

(1) Why can eggs bear such great pressure? This is why people can stand on eggs in acrobatics. )

(2)ppt shows the structural diagram of the turtle's back shell. Think about what benefits this structure will bring to turtles. Through the observation and discussion of teachers and students, it is obvious that the test is a powerful proof that the shell structure bears great pressure. When the gravity of bricks is transferred to the egg through the board and the bottle cap, they are evenly dispersed on the surface of the eggshell, which is why the eggshell structure can bear more pressure.

10 Student activity: Students make three-dimensional structures, frame structures and shell structures with thin bamboo sticks, toothpicks, plasticine, eggshells, glue, cardboard and Gaobao granules by experiencing structural grouping, and briefly describe the mechanical characteristics of these structures. Hands-on practice, the group sent representatives to show the results of the activities.

1 1 extension: structure and function

(1) Ride different kinds of bicycles (light bike, mountain bike, folding bike, tandem bike, stroller, bicycle for the disabled, etc. ) as an example, it shows that different structures have different bicycle functions, thus meeting people's different needs.

(2) Combined with other examples, the technical idea of "structure determines function" is summarized. (1) Listen

(2) List and explain examples of functional changes caused by structural changes in production and life.

12 after-class exploration

If there are many bridges and slopes on your way to school, what structural adjustments can you make to your bike to make it easier to ride? Finish after class

13 summary

Guide the students to sort out and summarize the contents of this section. Organize and summarize the contents of this section.

Seven, teaching reflection

The content of this section is introduced from structural examples that students are familiar with. By discussing the basic classification of force and structure, students can basically understand the meaning of structure. Through interesting experiments and students' hands-on experience, students have strengthened their understanding of different types of structural characteristics. However, the teaching content of this section is too much and the time is a little tight, which leads to the lack of teaching focus. One of the difficulties in this lesson is the concept of stress. In my teaching, I take the rope used for tug-of-war as an example to explain: why is a single rope easy to break, but multiple ropes are not easy to break when twisted together? So the concept of pressure is introduced. This concept is introduced to deepen the meaning of structure, but in teaching, I find that students can't accept it well and can only make a rough understanding. Therefore, in the study of structural strength, the concept of stress must be further deepened.

Annex I:

case analysis

Xanthium sibiricum and Velcro

The hunter walked through the bushes and his trousers were covered with annoying xanthium. Careful observation shows that the surface of Xanthium sibiricum is covered with many small thorns, and each thorn has a thin barb, which sticks to the fiber coat. George of Switzerland? After eight years of research, Doqens invented velcro to replace buttons, zippers, seaming agents and so on according to the structure of Xanthium sibiricum.

Birds and airplanes

The dream of human flying comes from the soaring of birds, and the prototype of aircraft comes from the bionic structure of birds. Birds can fly freely because it has a free and smooth shape that adapts to flight, and a hollow structure of wings and bones that makes the body lighter. Observing the structure of the plane, the wings on both sides are like a pair of wings spread by birds. The use of some lightweight materials makes the fuselage lighter, and the streamline of the whole plane is like the shape of a bird sprinting. It is birds that have inspired human beings and helped them realize their dream of flying.

Hawkeye and missile tracking system

The eagle can accurately identify animals on the ground at an altitude of several thousand meters because of its special eye structure. There is a groove on the retina of everyone's eye, which is called fovea. However, there are two fovea in the eagle's eyes, which have different functions. One is specially used to receive images of objects on the side of the eagle's head, and the other is used to receive images of objects in front of the eagle's head. In this way, the eagle's field of vision is much wider, and it can take into account both the front and the side. According to the structure of Hawkeye, people are developing Hawkeye missile system. This missile system can automatically find and identify targets and track attacks.

Annex II:

Test purpose:

Compare the pressure of different shapes of cardboard.

Test preparation:

1. Take the cardboard of the waste paper box and cut out three pieces of small cardboard with the size of 10cm×40cm respectively.

2. Take several books (used to support cardboard) and the weight of cardboard respectively.

Test process:

1. Support a piece of cardboard with two stacks of books, and keep adding heavy objects in the middle of the cardboard until the cardboard collapses, and record the weight of the heavy objects at this time.

2. Bend another piece of cardboard into an arch, and use two stacks of books at both ends to prevent the arch from extending. Weigh the object at the upper end of the arch until the arch collapses, and record the weight of the object at this time.

3. Bend the remaining cardboard into an arch with a span smaller than the last one, and add weights at the upper end of the arch until it collapses, and record the weight of the weights at this time (as shown in the figure).

Test summary:

1. Under what circumstances does cardboard have the strongest compression resistance?

2. What is the significance of this conclusion in practical application, and illustrate it with examples?

3. If the cardboard is folded into a corrugated shape, what will happen to the test results?

Annex III:

Five basic stress forms of members

The axial tension borne by an object.

The force with which an object is pressed.

Shear force two parallel forces acting on the same object, which are close to each other, equal in magnitude and opposite in direction.

Torsional force is a kind of force that uniformly applies forces in opposite directions at both ends of an object, causing the object to be twisted and deformed.

Bending force acts on an object, causing it to produce bending force.

Teaching Record of "Understanding Common Structures"

1. perceptual structure

(1) Students' hands-on experience: Four students are used as a study group, and a bag of materials (including six plastic rods 12cm long, 10 plastic rods, and some screws and nuts for connection) distributed by the teacher before class are used to make articles needed in life and production.

Teacher check: the same material, different study groups do different projects. There are A-shaped ladders, baskets and cages. ...

Instruct students to analyze these projects:

From the appearance, the structure is different.

From the point of view of use, the function is different.

(2) observation and thinking

① Show pictures of related structures in nature: show structural drawings such as honeycomb and eagle body.

② Guide students to analyze and discuss the structure diagram.

What are the advantages of beehive and eagle's body structure?

Why is the structure diverse and determines the nature of things?

2. Understanding of the concept of structure

Students are required to summarize the concept of structure from various structures in nature.

(1) Guide students to look for * * * the same thing from the body structure of honeycomb and eagle.

Structure refers to the orderly collocation and arrangement of various components of things.

Ask students to point out the key words in the structural concept: order and collocation.

Explore the structure

Inquiry learning of eagle eye structure.

(1) Let the students read the cases and think.

Students read the case: Hawkeye and missile tracking system.

Thinking: ① What do you want to say most after reading the case? Tell your deskmate or tell everyone.

Inspiration: Li Meilan's first sentence after visiting the cave was: "Wonderful!" What do you want to say after reading this case?

② Why study the structure?

Inspire students to answer: Through the analysis and research of various structures in nature, it gives people unlimited creative inspiration and enlightenment. People apply their achievements to the field of technology to better serve mankind.

(2) Further exploration

(1) Why can eagles accurately distinguish animals on the ground at an altitude of several kilometers?

After reading a book, students can answer: This is because its eye structure is special. There is a groove on the retina of everyone's eye, which is called fovea. However, there are two fovea in the eagle's eyes, which have different functions. One is specially used to receive images of objects on the side of the eagle's head, and the other is used to receive images of objects in front of the eagle's head. In this way, the eagle's field of vision is much wider, and it can take into account both the front and the side.

② Why should we study the structure of Hawkeye?

Student: According to the structure of Hawkeye, people are developing Hawkeye missile system. This missile system can automatically find and identify targets and track attacks.

Teacher: What do you mean by "Israeli targeted removal of Hamas"?

It shows that the strike accuracy of Hawkeye missile system is very high.

3. Further expand:

(1) Besides the Hawkeye missile system being developed according to the structure, what inspiration do you have?

(2) What would happen to the world if there were two grooves like eagles on the human retina?

Student 1: "People will have eagle's discrimination".

Health 2: "People will become Superman".

Third: "There will be new crimes".

……。

Teacher: "It seems that we humans are inferior to animals in many places. We can't fly freely in the air like birds, swim happily in the water like fish, run faster than dogs and beat harder than tigers. Why can man become the ruler of the animal kingdom? "

Teacher: With brains and learning, human beings have inherited thousands of years of knowledge in a few years or more, and made innovations on the original basis. Now entering the era of knowledge economy, the total amount of human knowledge will double in a few years. In order to be in an invincible position in the competition, we must keep learning.

(3) What other product structures are inspired by the structure of natural things in production and life?

Sweater, submarine.

Let the students read the case: Quebec Bridge collapsed.

Teacher: What caused the bridge to collapse?

Health: changing the bridge structure without authorization.

In the social field, there are also structural phenomena.

The content structure of an article affects the expression and quality of the article, and the personnel structure of an enterprise is related to the operation and efficiency of the enterprise.