The second unit line and angle
The first class:
Understanding of [Teaching Contents] (page 15- 16)
[Teaching objectives]
1, with the help of actual situation and operation activities, know straight lines, line segments and rays.
2. Straight lines, line segments and rays can be read correctly with letters.
3. Calculate the number of line segments in a simple graph.
[Teaching Emphasis and Difficulties] Understanding of straight lines, line segments and rays. Count the line segments in a simple figure.
[Teaching preparation] Teaching wall chart
[Teaching process]
I. Understanding straight lines, line segments and rays
1. Understanding straight lines, line segments and light from life situations
Show the wall chart on page 15, and let the students abstract straight lines, line segments and rays from the real situation. Then through the activities of "recognition", let them realize that they are all "straight" and describe the characteristics of these three characters in their own language.
2. The difference and connection between straight lines, line segments and rays.
Organize students to discuss the differences and connections between straight lines, line segments and rays: straight lines are infinitely long and have no endpoints; The ray is infinitely long and has only one endpoint; The line segment is limited in length and has two endpoints; Both ray and line segment are part of a straight line.
Second, letters read straight lines, line segments and rays.
1, self-study "Say" on page 15.
2. The whole class exchanges letters to read straight lines, line segments and rays.
Reminder: there is only one way to read rays, usually starting from the endpoint; There are two ways to read straight lines and line segments.
Third, count the line segments in simple graphics.
1, draw a picture:
Let the students know that countless straight lines can be drawn through the operation of the first question; You can only draw a straight line after two o'clock.
Understand the shortest line segment between two points by drawing and measuring the second question.
2. Practice:
Question 1: when counting line segments, instruct students to make statistics regularly, that is, in a certain order; At the same time, we should combine the expression methods of line segments, such as line segment AD and line segment DC.
Question 2 and Question 3: When comparing the lengths of line segments in these two questions, students are easily influenced by vision. Therefore, when talking about these two questions, let students first estimate which length of these line segments is to improve their enthusiasm for participation; Then organize students to discuss how to determine the correctness of their own estimates. For example, you can measure it with a ruler to verify.
[Blackboard Design]
Lines, segments and rays
Line: light: line segment:
Infinite length, infinite length and finite length
An infinite point has only one endpoint and two endpoints.
The first class:
[Teaching Content] Translation and Parallelism (page 17- 19)
[Teaching objectives]
1, with the help of actual situation and operation activities, know parallel lines.
I can draw parallel lines with a triangle ruler and a ruler.
[Teaching Emphasis and Difficulties] Draw parallel lines with a triangular ruler and a ruler.
[Teaching preparation] Teaching wall chart, wooden stick, triangular ruler and ruler
[Teaching process]
First, translation
Translation pencil: Let the students move the pencil on the square paper by hand and talk about the position relationship of the pencil before and after moving. Explain that the lines before and after the pencil translation are parallel to each other.
Second, parallel.
1, move:
Question 1: There are several groups of parallel lines in this picture. When guiding students to observe, let them move with sticks first, and then tell which line segments are parallel to each other.
Question 2: After translation, the parallel relationship between line segments is complicated, especially it may be more difficult for students to find the parallel relationship between some oblique lines. First, arrange some simple figures, such as diamonds and right triangles. Ask the students to talk about which segments of these figures are parallel to each other before and after translation.
2. 10% discount
Let students know more about the characteristics of parallel lines through the activities of folding and folding. In the activity, let the students fold in different ways. On this basis, guide students to discuss parallel folds. Then students can be encouraged to discuss how to explain that the two creases are parallel to each other.
Step 3 talk about it
In life, you can see all kinds of parallel lines every day. According to the pictures given in the book, think about what parallel lines you see in your daily life and communicate with your classmates.
First, draw parallel lines.
The method of drawing parallel lines with straightedge and triangular ruler in teaching.
Fourth, practical activities.
Find parallel lines from cuboids and cubes.
[Blackboard Design]
Translation and parallelism
Translation parallelism
The first class:
[Teaching content] Intersection and verticality (page 17- 19)
[Teaching objectives]
1, with the help of the actual situation and operational activities, to understand the vertical.
I can draw a vertical line with a triangular ruler.
3. According to the principle that the vertical line segment between points and lines is the shortest, some simple problems in life can be solved.
[Teaching Emphasis and Difficulties]
1. Draw a vertical line with a triangular ruler.
2. According to the principle that the vertical line segment between a point and a line is the shortest, some simple problems in life can be solved.
[Teaching preparation] Teaching wall charts, wooden sticks and triangular rulers
[Teaching process]
First, measure a quantity.
There are different situations when two straight lines intersect. When learning, let the students first put out various intersecting figures with wooden sticks or pencils, thus leading to the concept of intersection.
Observe and discuss the angle formed between these intersecting graphic lines, thus leading to a special angle-right angle. When students confirm the right angle relationship between two straight lines, they should know how to verify it with the right angle in the triangle ruler.
Second, a 10% discount.
Ask the students to fold the creases perpendicular to each other with the paper in their hands. Students can be completely allowed to fold themselves. After folding the paper, the teacher should guide them to learn to use their own verification methods. For example, the relationship between two creases at the right angle of a triangular ruler can be used to determine whether the two creases are perpendicular to each other.
Third, talk about it.
1, talk about the vertical line segment in the classroom and life.
2. Tell me which faces of the cube are perpendicular to each other.
Fourth, practice.
1, I said you put it.
Practice at the same table: one student first puts a stick on the table and asks another student to put another stick as required.
2. Have a look. What did you find?
Guide students to observe the vertical relationship between two lines in daily life. Q: How to determine whether two adjacent sides of a door frame are vertical, so that students can explore the measurement method by themselves.
Arrange students to measure with a triangular ruler to judge whether it is vertical or not, so as to improve students' awareness of applying mathematics.
Verb (abbreviation for verb) draw a picture
1. Determines which line is vertical.
2. Make it clear whether it is required to draw a vertical line: First, it is only perpendicular to a straight line; The other is not only vertical, but also passes through a certain point.
Six, quiz
Let students apply longitudinal knowledge to solve practical problems in life. Guide students to discover the law.
Make it clear that the vertical line segment from a point outside the line to the line is the shortest.
[Blackboard Design]
Intersection and verticality
Vertical intersection
The first class:
[Teaching Content] Rotation and Angle (Page 23-24)
[Teaching objectives]
1. Learn about boxers and rounded corners through operational activities.
2. Can distinguish right angles and rounded corners in life.
[Teaching Emphasis and Difficulties]
1, know boxers and rounded corners.
2. Can distinguish right angles and rounded corners in life.
[Teaching preparation] Each person uses two pieces of hard paper to make an activity corner.
[Teaching process]
I know boxers and rounded corners.
1, hands-on operation angle
Group of four: (1) Fix one of the cardboard strips and rotate the other.
(2) Observe the angle formed in the process of rotation and communicate with classmates.
2. Summary of report
Show the students all kinds of angles after rotation, name the angles they already know, and then lead out the boxers and rounded corners.
Second, talk about the Boxers and rounded corners in life.
1, give it a try: Question 1 When students talk about straight corners and rounded corners, they should guide students to explain how straight corners and rounded corners are formed. For example, after a person stands upright, his body and the horizontal bar form a boxer.
2. Tell me what other straight corners and rounded corners you have seen in your life?
Third, around which point do you rotate?
Try it: Question 2: Tell me which point a given figure rotates.
Homework: Exercise 1, 2.
[Blackboard Design]
Rotation and angle
Acute angle, right angle, oblique angle and fillet
The first class:
[Teaching Content] Angle Measurement (Page 25-27)
[Teaching objectives]
1, realize the necessity of introducing protractor and know protractor.
2, will use a protractor to measure the degrees of various angles.
[Teaching Emphasis and Difficulties]
1, know protractor.
2, will use a protractor to measure the degrees of various angles.
[Teaching Preparation] Everyone prepares a protractor.
[Teaching process]
First of all, realize the necessity of introducing protractor.
1, hands-on activities
Group work for four people: (1) Measure the size of ∠A and ∠B with ∠ 1
(2) They are all a little more than three times. Discuss what to do: measure from a smaller angle.
(3) Fold ∠ 1 to get ∠2, and measure ∠A and ∠B with ∠ 1.
2. Discussion and summary
Discussion: To measure how big an angle is, you can measure it with a specified angle. In order to unify the measurement units and facilitate communication, you specified an angle of 1 degree and used a protractor to measure the angle.
Second, know the protractor
Read 26 pages by yourself, think about the following questions, and then communicate in groups.
1, the unit for measuring angles.
2. The characteristics of protractor.
Third, measure the angle with a protractor.
1, try it yourself first: how to measure the size of ∠A and ∠B with a protractor.
2. Communicate measurement methods with classmates
3. Summarize the measurement method: emphasize the measurement method of "point-to-point coincidence and edge-to-edge coincidence".
4. Homework: Exercise 2, 3
[Blackboard Design]
Angle measurement
Units for measuring angles: methods for measuring angles:
The first class:
[Teaching Content] Drawing Corners (Page 28)
[Teaching objectives]
1, the angle of the specified degree will be drawn with a protractor.
I will draw some special angles with triangles.
[Teaching Emphasis and Difficulties]
1, the angle of the specified degree will be drawn with a protractor.
I will draw some special angles with triangles.
[Teaching Preparation] Everyone prepares a protractor and a triangle.
[Teaching process]
First, draw an angle with a specified degree.
1. Try to draw an angle with a specified degree.
Ask the students to draw a 60-degree angle: How many ways can you draw?
2, communication, summary
Communicate in the group first, and then communicate the painting in the whole class.
How to draw with a protractor? What should I pay attention to? (pay attention to the number of inner and outer circles, and you can estimate it after painting. )
How to draw with triangles? What should I pay attention to? Only some special angles can be drawn with triangles. )
3. Draw an angle of 150 degrees.
How many methods can you use?
Second, give it a try.
1. Try it: Question 1. Students first measure the degree of the corner of the red scarf with a protractor and then draw it.
2. Think and discuss how many degrees you can draw with a set of triangles.
Homework: Exercise 2, 3
[Blackboard Design]
Draw corners
Draw an angle with a protractor and an angle with a special degree with a triangle.
The first class:
[Teaching Content] Drawing Corners (Page 29-30)
[Teaching objectives]
1, review the related knowledge in this unit.
I will use what I have learned to solve simple practical problems in life.
[Teaching Emphasis and Difficulties]
Will use what they have learned to solve simple practical problems in life.
[Teaching Preparation] Everyone prepares a protractor, a triangle, a round piece of paper and a rectangular piece of paper.
[Teaching process]
First, review and apply parallel and vertical knowledge.
1, Exercise 2 1:
Talk about the relationship between parallel and vertical roads in a given graph. And guide students to explain how to determine the parallel or vertical relationship between two roads, some of which can be found intuitively and some need to be verified by right angles.
2. Exercise 2, Question 2:
According to their own living environment, talk about the parallel or vertical relationship between roads, and cultivate students' spatial concept. Let the students draw a sketch first, and then talk about the relationship.
Second, review the angle measurement with a protractor.
Exercise 2, questions 3 and 4: Ask students to estimate the angle first, and then measure it with a protractor.
Third, use knowledge to solve problems:
1, Exercise 2, Question 5:
This is an operation problem, which allows students to find laws and solve problems in the process of operation. Let the students operate, discuss, find the rules and solve the problems by themselves.
1, Exercise 2 Question 6:
Ask the students to find the right angle, acute angle and obtuse angle in the picture through independent observation, and then communicate with their classmates.