Teaching Design of Understanding of Centimeters and Meters by Jiangsu Education Edition
Teaching objectives:
1, a preliminary understanding of length units? Rice? Yes 1 m = 100 cm.
2. By estimating the length of some objects, a preliminary estimation consciousness is formed.
3, in the measurement activities, experience the fun of cooperative learning, develop the habit of doing things seriously.
4. Feel the close connection between mathematics and real life in specific measurement activities.
Teaching process:
First, create situations and ask questions.
Teacher: Kid, last time Ah Fu went to the tailor's shop to make a new coat, was the result satisfactory? Why? This time, Ah Fu came to make robes again. Please have a look. (Showing the scene of Ah Fu making robes) The master learned a lesson and bought a ruler. The master measured Ah Fu with a ruler and said, Length 1 meter. ? But the apprentice quickly said: no, no, it's 100 cm long. ? If you were Ah Fu, what questions would you have now?
Health1:1m =1oocm?
Health 2: The ruler hasn't changed. Why did the master and the apprentice say different things?
Teacher: Yes, how do you say it is different? What's the relationship between meters and centimeters? Today, in this class, we are going to learn rice. (blackboard title: understanding of rice)
Second, independent exploration,
(1) Know the length of 1 meter.
Teacher: We already know centimeters. How long is that centimeter? How long is 1 meter in your mind? Make a gesture.
Teacher: How long is 1 meter? Look, students, this is a meter ruler, and its length is exactly 1 meter. (The teacher draws a line segment) Give a gesture. Do you want to experience for yourself how long the rice is?
Student: Yes.
Teacher: Think about it. When measuring the length of 1 meter with a meter ruler, what should be paid attention to in order to ensure the accuracy?
Health: Straighten the meter ruler and hold both ends with your hands, not too much.
Let's try it together:
(1) Every child has a rice ruler in his hand. Please gently pull the two ends of the meter scale together. (Demonstration) What is the distance between your arms at this time? Don't move your arm, gently loosen your fingers, put down the meter ruler and have a look. The distance between your arms is 100 meters. Try again, work together on the same table, one measure and the other measure with a ruler.
(2) The measuring step is1m..
(3) Who will tell the teacher how long 1 meter is?
Health: arms, represented by 3 steps.
(2) Perceive the height of one meter.
Teacher: Look, put the meter ruler upright like this. Where is the height 1 m from the ground to the wall?
Please estimate the height from the teacher's feet to which position is 1 m? 1 meter just reaches the teacher's waist (the teacher stands in front of the meter ruler to measure). Where do you think 1 meter can go to your body? Two people at the same table cooperate and measure with a meter ruler.
Question: Why are they all 1 meter high? From the soles of the feet, the height from the teacher's waist is 1 m, and the height from the chin of this classmate is 1 m?
Health: The height of one meter is the same.
(3) contact with life.
Teacher: We recognize 1 meter. Can you find other objects with a length or height of about 1 m in the classroom?
Width of screen, blackboard, door, desk, etc. )
Teacher: Let's measure whether our estimate is accurate. (Ask two representatives to measure separately)
(4) contact estimation.
Teacher: We can't take a rice ruler with us every day. How can you estimate the length of an object if there is no meter scale around?
Health: The length of the outstretched arm is almost 1 meter, which can be estimated by measurement. We just measured about 65,438+0 meters in three steps. We can take a walk and see how many meters there are in about three steps.
Teacher: The children spoke very well just now. It seems that we have some extra rulers on us. Then we can use these rulers to help measure! How should I measure it? Please tick the box.
Teacher: What did you find through contact?
Health: To estimate the length of a shorter object, you can measure it by hand, and to estimate the length of a longer object, it is more appropriate to use step measurement.
(5) The relationship between meters and centimeters.
Teacher: Did the students find anything new when they used the soft ruler just now?
Teacher: Watch the soft ruler carefully. What's on it?
Health: There are numbers 0- 100, and there are scales.
Teacher: That's true. Let's see what we found.
Show courseware.
(1) to guide observation, and the courseware display scale is 0,10,20100 cm.
100 cm (1 m)
What did you find?
Health: I found that 100 cm was written under 1 m. So I think1m is equal to 100 cm and 100 cm is equal to1m.
Teacher: If we are good at observing and thinking in life, we will make many discoveries. Blackboard: 1 m = 100 cm
Teacher: The meter can be represented by the letter M. How to write this formula?
1m= 100cm
Teacher: Is Ah Fu's robe 1 m or 100 cm? Can it be solved now?
Health: 1 m and 100 cm are equal and have the same length.
(2) read the ruler.
We know the relationship between meters and centimeters by observing the soft ruler, so can the scale on the soft ruler be understood?
Show courseware: 0? 30cm
0? 42 cm
20? 40 cm
Three. Autonomous application.
Teacher: Looking at the scale, we also know the relationship between meters and centimeters.
1。 Now let's see who is faster. I say length, you signal.
2。 Through the tunnel.
Confused tunnel company
The length of the desk is much less than 1 meter.
The length of the pencil far exceeds 1 meter.
The length of the classroom exceeds 1 m.
Confident and authentic. Love
This table is 28 meters long.
The length of this pencil is 10 cm.
The length of the classroom is 1.30 cm.
4. Class summary. What did you learn from this course?
Reflections on the cognitive teaching of centimeters and meters
This week, I taught the understanding of centimeters and meters, mainly measuring the length of textbooks, pencil boxes and desks with a ruler. This is the learning content that children are interested in. Many children find mathematics interesting and fun. However, in my homework, I often encounter such a ridiculous homework:? A big tree is 5 cm tall? 、? Xiaohong's height 130m? 、? The bed is 2 cm long? This is a mistake. The main reason why students make this mistake is that they don't have a vivid representation of the actual size of the length unit. The concept of length unit is the first time for sophomore students. What are centimeters and meters? They may have heard of it before studying, but students are not very clear about how long a centimeter is and how long a meter is. Therefore, we should pay attention to the formation of the concept of measurement unit in teaching and implement the requirements in this respect.
The difficulty of this part of the teaching content is to establish the representation of 1cm and1m. According to my observation, many children are lacking in this part, mainly because they did not establish a good intuitive impression when they first came into contact with the concept of length, but operation is the best way for children to establish this appearance. Therefore, in practical teaching, students should know how long 1 m and 1 cm are through practical activities such as watching, comparing and measuring, and start with common objects in life for students to observe and compare. So in teaching, I asked them to observe 1 cm with their eyes first, then close their eyes and think about the length of 1 cm, and finally open their eyes and draw the length of 1 cm with their fingers. According to the impression of 1 cm, estimate the length of your finger, palm, pencil case, eraser, exercise book, etc. When establishing the appearance of 1 m, I mainly draw the length of 1 m with open arms. In addition, I also use the meter ruler to measure which part of the student's body is 1 meter, including neck, chest and mouth. So students also know that their height is more than 1 m, that is, more than 100 cm. Finally, contact the height of adults, so that students can understand that the height of adults is generally less than 2 meters, 1 meter or more, so the door must be higher than people, and the bed must be higher than people, so that everyone can go in and out from this door and sleep on this bed. After such practical activities, students are unlikely to take height as a reference: when will I show the mistake of a bed length of 2 cm? This big tree is 4 cm tall? When correcting the questions, the students were already laughing their heads off and gesticulating with 4 cm long fingers, saying: The tree is so high that it is not as long as a leaf. ? It seems that students have clearly established the representations of 1cm and1m. Through this exercise, students have the correct choice and use of length units, and the correct rate will be greatly improved.
In class, teachers should let students relate the things around them with the knowledge they have learned, and provide students with a platform for practice, experience, feeling and thinking, so that students can learn knowledge in relaxed and happy activities.