Understanding of seeking a circle: a teaching plan

Understanding the teaching plan design of circle

Teaching purpose: 1. Master the names and characteristics of each part of the circle; Can draw circles with compasses.

2, with the help of hands-on activities, cultivate students' ability to use what they have learned to solve practical problems.

3. The infiltration of knowledge comes from practice and the idea that the purpose of learning is to apply what you have learned.

Teaching emphasis and difficulty: master the names and characteristics of each part of the circle. Mastering the circle chart.

Preparation of teaching AIDS: multimedia courseware, compasses, rulers, etc.

Preparation of learning tools: various round objects, scissors, crayons, rulers, compasses, circles, pieces of paper, etc.

Main teaching process

First, introduce new lessons by combining exercises and dialogues.

Introduction: I am very happy to study and study a math problem with my classmates in Class Six (Five) today. We knew this circle before. Can you find out which things in life are round? (Students emphasize-refers to the surface of an object)

Teacher: It seems that everyone usually pays attention to observation. Please draw two circles of different sizes and cut them out before class. Are you ready?

Teacher: Lift them up and let's have a look at each other. Looking back at the process of drawing and cutting a circle, can you tell me what a circle looks like? (The teacher has a circle in one hand)

A circle has no edges and corners, but its sides are curved. The edge of a circle is a curve. )

Teacher: The students observe carefully. The edge of a circle is curved, which is different from that of a rectangle or a square. Today, we are going to study the curve figure on this plane. (blackboard writing topic)

Second, guide the exploration of new knowledge.

1, Guide: What secrets are hidden in the circle? Let's do a little experiment. Fold your circle in half, fold it again, fold it several times, draw creases, see what you find, and report your findings in the group. Finally, see who gets more. (1 min)

2. Students begin to operate, discuss and communicate. After a few minutes, the report appears in terms of center, radius and diameter. (5 minutes)

Teacher: Your group has observed very carefully! You have found a lot. Now let's sort out what we just found.

3. Display the query results. Fully understand the characteristics of the circle with the help of multimedia courseware (8 minutes)

Who will tell the teacher what you have found?

What is the reason?

How did you find out?

Combine students' communication and report the results of inquiry, and guide them in time. Mainly from the center, radius, diameter and other aspects. Here, we should pay special attention to helping students master new knowledge through blackboard writing and make purposeful arrangements.

Default blackboard writing:

Understanding of Circle-Plane Curves

A point on the center of the circle (O) determines the position of the circle.

Radius (R): The line segment connects the center of the circle with any point on the circle, ensuring that the size and length of the circle are equal (in the same circle).

The line segment with diameter (d) passes through the center of the circle, with both ends on the circle and equal length.

Relationship between radius and diameter d=2r r=d/2

4. Learn to draw a circle (5 minutes)

How do you draw a circle?

The courseware shows how to draw a circle. Then the students began to practice, emphasizing what should be paid attention to when drawing a circle. -Determination of the size and position of the display circle

The school plans to build a flower bed with a diameter of 20 meters. Can you draw this circle for the school? Student demonstration operation

Third, application development.

1, basic exercise (4 minutes)

The <1> projection shows the radius and diameter of the following circle.

< 2 > Correlation calculation of radius and diameter

< 3 > Judgment and identification of concepts

2. Application exercises. (10 minutes)

← 1 \8592; Why are the wheels round and where should the axles be installed? If the wheels are made into squares and triangles, how will we feel sitting on them? Combined with courseware demonstration

〈2〉 Can you explain some life phenomena with the knowledge of circle learned today?

When a bonfire party is held, people always form a circle unconsciously. Why?

What will happen if you throw a pebble on a calm lake? Why?

Moon cakes are usually made into circles. Why? )

It seems that many phenomena in life contain rich truths, which need us to explore, understand, explain and apply constantly.

< 3 > The students are very tired after learning, so let's relax. The teacher guessed a riddle for everyone. A man nailed a stake in a meadow and tied a sheep there with a rope. (with computer graphics)

Please guess a word first. (Many students say they can guess the "sample") Then students guess the fruit names of two words, and students guess strawberries (the homonym of missing grass) under the inspiration.

Teacher: Does herding sheep have anything to do with what I learned today? Let's take a look at the maximum range of grazing for sheep, shall we? Use computer to demonstrate the situation that the sheep tightens the rope and rotates once, so that students can intuitively see that the maximum range of grass that the sheep can eat is a circle. Does the rope tied to the sheep have anything to do with this circle? What is the circle of the stake nailed there? (It is the center of this circle) What should I do if I want this sheep to eat more grass? (Make the rope longer, that is, enlarge the radius) What should I do if I want the sheep to eat grass in another place? (you can move the stake one position, that is, the position of the center of the circle), which shows what the radius and center of the circle have to do with the circle? The radius of a circle determines its size, and the center of the circle can determine its position. )

Fourth, the class summary (3 minutes)

1, query (Is basketball round? Can the letters representing the center, radius and diameter be changed at will? )

2. What did you learn in this class?

Anyway, the teacher thinks that the students' academic performance is good. I suggest that everyone reach out and come to a satisfactory conclusion together. (Period is an integer)

Extension:

1, drawn with a circle

2. Tell me about the circle in my eyes.