Tisch
[Teaching objective] 1. Understand the parallel, perceive the characteristics of parallel lines, learn to draw parallel lines initially, and understand the application of parallel lines in life.
2. Cultivate the ability of spatial imagination and the awareness and ability to connect with reality.
3. Feel the value of mathematics and cultivate interest in learning mathematics.
[Teaching process]
First, parallel understanding
1, preliminary perception, trying to judge
Division; At the beginning of the course, let's watch a short video (play the video)
Teacher: What are the children doing in the video? Health: Open the window.
Teacher: What does this window do when it opens?
Health: Translation
Teacher: Yes, we learned translation last semester. You learn very well. We saw that one side of the window was in this position at first; After translation, reach this position. Do you know the relationship between this side and the position of this side?
Health: parallel
Teacher: You have a wide range of knowledge. In this class, we learn parallel lines together.
Teacher: Do you know parallel lines?
Miss Gao, here are some photos. Please look for it. Which pictures show the parallel lines in your mind?
Health 1: 1, pictures 5 and 7.
Health 2: Just the picture 1.
Health 3: 1 and 5
Teacher: It seems that students have their own understanding of parallel lines. Is your idea right? I believe you will get a definite answer after learning this lesson.
2. Fully experience and explore the essence.
Teacher: So what exactly are parallel lines in mathematics?
Let's see:
These two straight sides of the window can be regarded as two line segments. If this line segment extends infinitely to both ends. Close your eyes and imagine what will happen if you see two straight lines? Will it intersect?
Health: No.
Teacher: It is said that seeing is believing. The parts I see of these two straight lines don't intersect, but I can't see them after infinite extension. What makes you say that they will never meet?
Health 1: Because stretching won't bend over.
Health 2: They won't get closer and finally get together.
Health 3: The width between them will never change.
Teacher: The width is the same, but the distance between them is the same everywhere. (courseware verification)
Because their distance is equal everywhere, they will always keep this distance after infinite extension, so they will never intersect.
3. Improve the concept and then judge.
(Written on the blackboard, dictation: Two lines that never intersect are parallel to each other)
Teacher: Two straight lines are parallel to each other. We can also say that one of them is parallel to the other.
If we label two straight lines with names, AB and CD respectively, we say that straight line AB is parallel to straight line CD and record it as AB∨CD.
Teacher: If I tilt these two straight lines now, will they be parallel to each other now?
Health: parallel.
Teacher: Why?
Health: Because they will never meet.
Teacher: Let's review the eight pictures just now.
(1) Can you find the parallel lines here with the concept you just learned? Give a good reason.
(Pay attention to students' first judgment of mistakes, controversies or uncertainties. Are parallel lines, why; No, why not. Make students have a deeper understanding of parallelism)
There is only one straight line in Figure 7. Can you help him find a straight line parallel to him one day?
Health: Figure 1
Teacher: Above or below?
Health: Both lines are parallel to the straight line in Figure 7.
4. Parallel lines in life
Teacher: These straight lines are parallel to each other. Can you still find such parallel lines in your life?
Health 1: Up and down the blackboard.
Yes, the opposite sides of the blackboard are parallel to each other.
Health 2: These two sides of the table are parallel to each other.
Teacher: You mean the two sides of the table are parallel to each other. I hope the students can express clearly.
Teacher: Miss Gao has some pictures here. Can you find parallel lines from them?
Health 1: The opposite sides of that picture are parallel to each other.
Health 2: The two sides of the stair handrail are parallel to each other.
Health 3: The vertical guardrail and the vertical guardrail are parallel to each other.
Teacher: Yes, now let's look at this place again.
Health 1: Climbing and doing are parallel.
Health 2: The reverse sides of the tiles are parallel.
Health 3: The opposite sides of the flower bed are parallel.
Teacher: There seem to be many parallel lines in life. There is a child named Naughty. He found that all the windows were too similar and not creative. So he designed this new type of window.
Teacher: Can you accept naughty designs? Why?
Health 1: I disagree, because in this case, the window can't be moved.
Health 2: If the window moves to the right, it will fall.
Teacher: It seems that parallelism is not only beautiful, but also useful.
What the students just discovered is still. Now let's look at the parallel lines in motion.
Every Monday, we will hold a flag-raising ceremony. The top of the national flag was translated from here to here. They are parallel to each other.
Teacher: Look at this picture again. The arrow turns from here to here Students, the line segment HG was here at first, and then moved to H 1G 1. Is the line segment HG parallel to the line segment H 1G 1? Can you find similar parallel lines from the arrows before and after translation?
Student: the line AD is parallel to the line A 1D 1.
Second, draw parallel lines by hand.
1, Teacher: Now the students all know the parallel lines. Can you draw parallel lines on the white paper?
Please take out the blank paper and look at the first question. Teacher Gao drew a straight line for you. Now can you draw its parallel lines?
Note: think carefully when drawing. Can you guarantee a certain degree of parallelism according to your painting?
Health: Hands-on operation
Display: 1, measuring distance. 2. Draw along both sides of the ruler. 3. Ruler translation
Teacher: How many parallel lines can you draw?
Health: countless articles.
Teacher: Now, do you have anything to say about these three methods?
Health: (talk about the limitations of various methods)
Teacher: It seems that each method has its own advantages and disadvantages, so you should choose the most suitable method when drawing parallel lines.
2. Teacher: Now, please choose the appropriate method to finish the second question.
The teacher covered up the translation method of the ruler,
Attention points: 1, 2, 3, 4, and painting.
Teacher: Now please draw a straight line on the paper.
Health: ...
Teacher: Now, please exchange blank sheets at the same table and draw a parallel line for the straight line drawn at the same table. Let one person draw another first, see if the one at the same table draws correctly, and then exchange. Do you understand what I mean? All right, let's get started.
Third, summarize and communicate
Do you have any new knowledge about parallel lines after learning this lesson?
With the deepening of learning, our understanding of parallelism will become more and more profound.
Fourth, expand
Teacher: Please look at these two lines. Are they parallel to each other?
Teacher: Which side of the cuboid are they on?
Teacher: Please pay attention (turn the box so that the two straight lines are not on the same plane)
Teacher: Will these two straight lines intersect? Are they parallel?
Do you think we should add a precondition when we say that two straight lines are parallel?
Summary: In the same plane, two lines that never intersect are parallel to each other.
[Blackboard Design]
Translation and parallelism
Translation parallelism
extreme
[Teaching objectives]
1. Guide students to perceive parallel phenomena in life through observation and discussion.
2. Help students understand that parallelism is the positional relationship between two straight lines in the same plane and know parallel lines.
3. Cultivate students' spatial concept and spatial imagination ability, and guide students to establish the learning consciousness of cooperative inquiry.
[Teaching Emphasis] Correctly understand the concepts of "in the same plane" and "parallel to each other" and develop students' spatial imagination.
[Teaching Difficulties] Draw Parallel Lines
[Preparation of teaching AIDS and learning tools] Courseware, watercolor pens, rulers, triangles, sticks.
[Teaching process]
First, the introduction, observation and discovery of the environment
Open the window.
What is the action of this window in the process of opening?
Yes, we learned translation last semester, and you learned it well. We saw that one side of the window was in this position at first; After translation, reach this position. Do you know the relationship between this side and the position of this side?
In this class, we learn parallel lines together.
Teacher, here are some pictures. Please look for it. Which pictures show the parallel lines in your mind?
It seems that students have their own understanding of parallel lines. Is your idea right? I believe you will get a definite answer after learning this lesson.
Second, actively participate in exploring feelings.
These two straight sides of the window can be regarded as two line segments. If this line segment extends infinitely to both ends. Close your eyes and imagine what will happen if you see two straight lines? Will it intersect?
Teacher: It is said that seeing is believing. The parts I see of these two straight lines don't intersect, but I can't see them after infinite extension. What makes you say that they will never meet?
The width is the same, in fact, their distance is equal everywhere. (courseware verification)
Because their distance is equal everywhere, they will always keep this distance after infinite extension, so they will never intersect.
(Written on the blackboard, dictation: Two lines that never intersect are parallel to each other)
Two straight lines are parallel to each other, and we can also say that one of them is parallel to the other.
If we mark two straight lines AB and CD, we say that straight line AB is parallel to straight line CD.
If I tilt these two straight lines now, are they parallel to each other now? Why?
Parallel lines in life
These lines are parallel to each other. Can you find such parallel lines in your life?
There seem to be many parallel lines in life. There is a child named Naughty. He found that all the windows were too similar and not creative. So he designed this new type of window.
Can you accept naughty designs? Why?
What the students just discovered is still. Now let's look at the parallel lines in motion.
Every Monday, we will hold a flag-raising ceremony. The top of the national flag was translated from here to here. They are parallel to each other.
Look at this picture again. The arrow turns from here to here Students, the line segment HG was here at first, and then moved to H 1G 1. Is the line segment HG parallel to the line segment H 1G 1? Can you find similar parallel lines from the arrows before and after translation?
Draw parallel lines
The teacher demonstrated the translation method of triangular ruler.
Attention points: 1, 2, 3, 4, and painting.
Students draw pictures.
Third, solve problems with knowledge.
Fourth, class summary, summing up new knowledge.
Do you have any new knowledge about parallel lines after learning this lesson?
With the deepening of learning, our understanding of parallelism will become more and more profound.
Tisso
[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.
Third, 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.