Present situation: "Angle" is the third section of Chapter 4 of "Basic Plane Graphics" in the first volume of Grade 7 of Beijing Normal University Edition. It is the continuation of learning the knowledge of straight lines, rays and line segments, and it is also the basis of learning other graphics.
It lays a foundation for the comparison and operation of learning angles in the future, and is also of great significance to the future geometry learning. Function: 1. It can cultivate students' observation ability, inquiry ability, abstract generalization ability and mathematical thinking method, and lay the foundation for students' innovative learning and active learning. 2. Make students know the laws from concrete to abstract, from perceptual to rational, and realize that knowledge comes from practical materialism.
(2) Analysis of learning situation
Grade seven students are very active, easily distracted and like to express their opinions. Hope to get the teacher's praise. In teaching, I grasp this characteristic of students, arouse students' interest through intuitive demonstration, focus on the classroom, and express my views through students' hands-on drawing.
Class arrangement
1 class hour
Teaching objectives
Knowledge and skills
Understand the definition of angle and related concepts, and understand boxers and rounded corners from the perspective of teaching design of junior high school mathematics micro-courses;
Process and method
Improve students' ability to look at pictures and learn to look at problems from the perspective of action changes.
Emotional attitudes and values
In the real situation, we can experience and understand the mathematical activity process from the perspective of junior high school mathematics micro-course teaching design, feel the richness of the graphic junior high school mathematics micro-course teaching design world, enhance aesthetic awareness and stimulate students' curiosity.
focus
The concept of angle;
difficulty
Understand the concept of angle from the perspective of movement
training/teaching aid
Multimedia courseware, triangle board
teaching process
First, the introduction of new courses.
1. Show courseware: Can you find the familiar plane figure in the picture?
2. Is there such a graph in life?
3. What are the characteristics of these figures?
Second, the new curriculum teaching
1, the concept of learning angle;
(1) Observation chart thinking: What is the teaching design angle of junior high school mathematics micro-lesson? The definition of angle is obtained: the figure composed of two rays with common endpoints is called an angle. This common endpoint is called the vertex of the angle, and these two rays are called the edges of the angle. (You can refer to the illustration)
(2) Can we draw a corner in the teaching design of junior high school mathematics micro-courses? Please draw a corner in the exercise book.
(3) A set of exercises, tell the edge of the top corner of the corner.
(4) The teaching design of junior high school mathematics micro-lesson angle can get the angle through the minute hand rotation of the clock. Is there such a person in life? Students give an example to give another definition of angle: the figure formed by the rotation of light around its endpoint is also called angle. The ray at the starting position is called the starting edge of the angle, and the ending position is called the final edge of the angle.
(5) Understand the second definition of angle, right angle, right angle and fillet through courseware animation demonstration.
Teaching design of junior high school mathematics micro-course from angle three. A set of exercises? Judge:
(1) A graph composed of two rays is called an angle. ( )
(2) Is it a straight line? ( )
(3) The ray is a rounded corner. ( )
(4) Turn an angle into a magnification of 10.
Looking in the mirror, the degree of the angle is also enlarged by 10 times. ( )
(5) Angle has nothing to do with side length. ? ( )
Three. abstract
Students summarize the two definitions of the corner, teachers' comments, deepen the impression, encourage students to dare to express their opinions and benefit from the exchange.
Four. Homework: Workbooks 4,3, 1 Angle >
The teaching goal of the first volume of the seventh grade mathematics angle courseware 2;
1. The rule that "the sum of the internal angles of a triangle is 180 degrees" is discovered and verified through operational activities.
2. In the operation activities, cultivate students' cooperative ability and practical ability, and develop students' spatial concept. And solve problems with new knowledge.
3. Make students have a scientific experimental attitude, stimulate students' interest in learning mathematics actively, and experience the joy of success in mathematics learning.
Teaching emphasis: explore the discovery and verification process of the rule of "triangle internal angle and 180 degree" and summarize the rule.
Teaching difficulties: the guidance of different inquiry methods and students' flexible application of laws.
Preparation of teaching AIDS: Courseware, students prepare different types of triangles and protractors.
Teaching process:
First, the creation of scenarios, leading to problems
Shaped like a mountain, as steady as Mount Tai.
Learning is not easy.
(Type the graphic name) Triangle (blackboard writing)
2, guess the triangle (courseware)
Teacher: Here are three triangles, and a part of each triangle is covered by a rectangle. Do you know what triangle this is?
Teacher: When you ask the third figure, what are the two corners that are covered?
Will it be two right angles? Why?
Guide students to start thinking about "What is the sum of the internal angles of a triangle". )
3. Lead the topic.
Teacher: It seems that there must be some mystery hidden in the inner corner of the triangle. In this lesson, we will learn about the triangle angle "the sum of the angles inside the triangle". (blackboard writing topic)
Second, explore new knowledge.
1, and the sum of the interior angles of the triangle.
(1) What is the internal angle of the triangle (courseware)
All three angles in a triangle are interior angles of the triangle. For the convenience of research, we label the three internal angles of each triangle as ∠ 1, ∠2 and ∠3 respectively.
(2) Sum of internal angles of triangle
Teacher: What do you mean by inner corner sum?
Health: The sum of the degrees of the three angles of a triangle is the sum of the inner angles of the triangle.
(Let more students speak)
2. Guess.
Teacher: What is the sum of the inner angles of this triangle?
Teacher: Is the sum of the internal angles of all triangles 180? Are you sure?
Default 1 division: Everyone has different opinions. We must find a way to verify the sum of the interior angles of a triangle. What method can be used to verify?
3 Operation verification: teamwork.
Select your favorite 1 triangle and your favorite verification method.
(The teacher first provides students with sufficient research materials, such as three types of triangles (the sizes of triangles are different among groups), scissors, protractor, blank paper, ruler, etc. And have enough time to ensure that students can really experiment, operate and explore, and explore problems through measurement, folding, spelling and painting. )
4 student report.
(1) Teacher: Some newspapers measured 180, while others did not. Why is this happening?
Teacher: Is there any other way to verify it?
(2) Cutting and assembling
A, students take the stage to demonstrate.
Please work in groups of four to verify other triangles with his method.
C. show students' works.
D, the teacher shows.
(3) Folding
Teacher: Is there any other verification method?
Teacher: I found the method of folding in the computer. Please have a look at how he folded it (courseware demonstration).
Encourage students to actively use their brains to explore ways to solve problems from different ways, at the same time, give students enough time and space, constantly let each student participate, pay attention to let students solve problems in the process of observation, operation, analysis, reasoning and imagination, and develop spatial concepts and reasoning ability. )
(4) Mathematical culture
Teacher: In addition to the methods we thought of in this lesson, there are many ways to verify that the sum of the interior angles of a triangle is 180. In junior high school, we need a more rigorous method to prove that the sum of the inner angles of a triangle is 180. As early as 300 years ago, a scientist verified that the sum of the internal angles of any triangle was 180( 12 years old). As early as more than 300 years ago, this famous French scientist had discovered that the sum of the internal angles of any triangle was 180 degrees, and he was only 12 years old.
5. Consolidate knowledge.
(1) Teacher: Do you still have any questions about the sum of the angles in a triangle? Now we can say for sure: What is the sum of the internal angles of a triangle? Degree.
(2) Why can't we draw 1 two right-angled triangles before class?
Does 1 triangle have two obtuse angles?
(3) Teacher: We have a clear understanding of triangles.
Show two triangles and tell the sum of the inner angles.
Put two small triangles together and ask: What is the sum of the internal angles of the big triangle? Degree.
Teacher: Why not 360?
Third, solve related problems.
Teacher: Next, use the inner angle of the triangle and us to solve some related problems!
1. Look at the picture to find the degree of unknown angle.
2. There are 10 questions on 88 pages in the book.
Teacher: What triangle did we use just now?
3. Teacher: If you don't know any of them, or only 1 angle, can you know the degree of each angle of a triangle?
Find the degree of each angle of the triangle below.
(1) My three sides are equal.
(2) I am an isosceles triangle with a vertex angle of 96.
I have an acute angle of 40 degrees.
4. Judges.
5. Find the sum of the internal angles of quadrilateral and pentagon.
It's time for class to be over. Let's have a challenge. Do you dare to accept the challenge
If you find the sum of the internal angles of the 10 polygon, will you find it? What did you find?
My purpose is not only to let students solve the sum of the internal angles of polygons, but more importantly, to let students flexibly use knowledge points and cultivate their spatial thinking ability. )
Fourth, summary.
Teacher: What did you learn from this class?
Five, the blackboard design:
The sum of the internal angles of a triangle is 180.
∠ 1+∠2+∠3= 180
Generosity; tolerate
scissors
Folding and spelling