The course plan is as follows:
First unit
1. Subject: Understanding centimeters by unifying length units.
Teaching objectives
(1) Knowledge and skills: Through practical activities such as taking a look, comparing and measuring, we can know the length unit centimeter, initially establish the appearance of 1 centimeter, and can measure the length of an object (limited to the whole centimeter) with a ruler.
(2) Process and method: Through students' observation, inquiry and other learning activities, students can establish their understanding of length units in their own creative activities.
(3) Emotion, attitude and values: Understand the relationship between mathematics and life, and cultivate students' innovative consciousness.
Teaching focus
Establish the concept of length of 1 cm.
Teaching difficulties
Measure the length of an object with a student's ruler (only a whole centimeter).
Teaching preparation
Multimedia courseware, meter ruler. Students prepare student rulers.
teaching process
First, introduce a conversation
Teacher: Students, who is taller than your mother and teacher? Who is short?
How much higher? How much shorter? Make a gesture. Can you know exactly how tall and how short?
"How tall" and "How short" are actually comparing the length of the human body, which requires the use of length units.
The students answered.
Compare students as required.
Second, explore new knowledge.
(1) unified unit of length
How did the ancients do it when they didn't invent the unit of length?
(Example 1 scene diagram. ) What information have you learned by observing these pictures?
What do you think of their methods?
The teacher summed it up. Teachers and students measure desks.
Communication report: How long is the desk?
The teacher asked a question: I only measured 3 feet. We all measure the same table. Why is the result different?
Follow-up: How can we get the same result? Is there any good way?
(2) overall perception, knowing centimeters.
1. Observe the ruler and know the scale.
Please take out your prepared ruler and compare your ruler with your deskmate's ruler to see what they have in common.
The teacher points out the scale line, O scale and length unit "cm" and clearly measures the length of shorter objects, generally in "cm".
2. I know 1 cm.
The teacher pointed out: this scale 0 is very important, it is like the starting line, which means starting from here. The length from scale 0 to scale 1 is 1 cm. (blackboard writing: 1cm)
Which section of the ruler is also 1 cm in length? Who will point it out? What did we find?
Teacher: Because the length of each grid is the same, there is a uniform standard for measuring the length of objects with a ruler.
Students, what do you think of the length of 1 cm?
Follow-up: What objects in life are about 1 cm in length?
The teacher shows the width of index finger, the width of Tian Zige and the length of thumbtack.
In a word, the width of our index finger is about 1 cm. Can you also say a sentence in l centimeters?
3. Know a few centimeters.
Teacher: Just now the students met 1 cm. Now the teacher will increase the difficulty. How many centimeters is the length from 0 to 3 and from 0 to 7?
4. Teaching Example 3 (Measure a quantity).
(1) Take out the note prepared before class, draw its length by hand and tell how many centimeters it may be.
The teacher explained and demonstrated:
(2) If the ruler is broken and the minimum scale is 2, can you still measure the length of this note? How to measure?
5. Practical application. Pick up the math book and find the shorter side of the cover. How long is this short side? Measure it again to see if your estimate is accurate. Measure the length of the long side of the math book again.
Third, consolidate new knowledge.
1. Complete "Doing" on page 4 of the textbook.
2. Complete the first 1 question in the textbook Exercise 1. Estimate a few centimeters before measuring.
3. Complete the second question in the textbook "Exercise 1".
Note: If it is close to 8 cm, we say it is about 8 cm.
How many centimeters does it take to measure at the same table? Measure the distance from toe to toe.
Four. abstract
What did you get from this lesson?
Summary: Through the study of this lesson, we know that the length of an object must be measured in a unified length unit, and we also know the length of 1 cm, and we will use the ruler in our hands to measure the length of the object around us.
How to teach second-grade children well
First, create opportunities for students to think, think and ask questions. For example, the "angle understanding" learned in the second grade textbook. For what is an angle, the names of various parts of the angle, and "the size of the angle has nothing to do with the length of the side", the students have learned "Are there any questions?" The student answered "no problem". Is there really no problem? "Then let me ask a question." I asked a question: "Why is the size of the angle irrelevant to the length of the side?" After discussion, we understand that the edge of an angle is a ray, and the ray has no length, so the size of the angle has nothing to do with the length of the edge. The size of the angle depends on the opening degree of both sides. The teacher demonstrated asking questions from the students' point of view. Over time, students have the consciousness of asking questions. While guiding students to ask questions, it also cultivates students' ability to think and solve problems actively.
Second, use life knowledge to teach. For example, Xiaohong made 18 paper flowers for her classmates. How many flowers are left? This is a two-digit number MINUS two digits. If you do it in life, students will understand the meaning. Therefore, some practical problems can be solved by students' life experience first, and then by mathematics knowledge, so that students can understand the meaning of the problem.
Third, use the social environment to improve the practical application ability of mathematics. For example, when studying statistics, we can take students to shopping malls or society, and use the newly learned statistical knowledge to collect useful information and knowledge through observation, measurement and comparison.
Fourth, create opportunities for students to think, think and ask questions. For example, the second-grade textbook has learned "the understanding of angles", and students already know what an angle is and the names of its parts. "The size of an angle has nothing to do with the length of its sides."
"Are there any questions?" The student answered "no problem". Is there really no problem? "Then let me ask a question." The teacher asked a question: "Why is the size of the angle irrelevant to the length of the side?" After discussion, we understand that the edge of an angle is a ray, and the ray has no length, so the size of the angle has nothing to do with the length of the edge. The size of the angle depends on the opening degree of both sides. The teacher demonstrated asking questions from the students' point of view. Over time, students have the consciousness of asking questions. While guiding students to ask questions, it also cultivates students' ability to think and solve problems actively.