[Teaching objectives]

1. According to the specific situation, feel and know the mass unit ton, and know how much a ton weighs.

2. Master "one ton = 1000 kg" and make a simple conversion.

3. According to the specific situation, improve the ability to estimate the quality of objects and feel the connection between mathematics and real life.

[Instructional design]

(A) create a situation to stimulate interest in the introduction

Introduction to riddles.

Teacher: Before class, the teacher gave us a riddle. His ears are like a cattail leaf fan, his body is like a hill, and his nose is long. He helps people to work. What kind of animal is this? Yes, it's an elephant. These students are very clever. Guess how much the elephant weighs.

Students may answer: it must be heavy, and it will be measured in grams, kilograms, or tons; Some people may also question: How many kilograms is that? )

The teacher leads the students to think: Do you think it is appropriate to explain the weight of elephants with the mass units grams and kilograms we have learned? So as to naturally derive the mass unit "ton". Ton is a large unit of mass, so what is 1 ton?

(Leading topic: 1 ton? )

(B) the initial perception, the formation of construction

Show the pictures in the book with multimedia.

1. Show the pictures and let the students read the math information.

2. Ask students to calculate the formula independently, and then exchange the calculation results.

Three buffaloes weigh about 1000 kg; 10 barrel of oil weighs about 1000 kg;

20 bags of flour weigh about 1000 kg; 40 people weigh about 1000 kg.

(3) independently explore and solve problems

1. Team report. What did you find?

The teacher answers the blackboard according to the students: 1t = 1000kg, and the introduction is expressed in letters: 1t = 1000kg.

2. Get in touch with life and learn new knowledge.

(1) shows that many objects in life need to use the mass unit ton.

(Multimedia demonstration) Ask the students to say the meaning of each picture, and the teacher will add it.

(2) Ask students to give more examples from their lives and analyze them together.

3. Complete the exercises in the book independently, inspect the teachers and guide the students with learning difficulties.

Fill it out.

4 kg = () g 3 tons = () kg

5000 grams = 2000 kilograms

18t = () kg () kg = 6t

(d) Returning to life and expanding applications.

1. Mathematical story.

Do the students know the story "Cao Chong is called an elephant"? Let the students talk about it, and then the teacher will tell you the story (using multimedia)

(1) Let the students discuss: Why do you use this method to represent elephants?

How much does this elephant weigh?

Please calculate for yourself and see how much this elephant weighs.

2. Today, we learned the quality unit ton. Please investigate the shadow of ton in our life. How many things add up to about a ton.

3. Collective feedback, reflection and summary

Let the students talk about what they have gained from this class first. If necessary, the teacher can supplement it as a participant.

Teaching reflection

First, contact with real life and explore mathematical knowledge

When teaching the unit "ton", students seldom come into contact with it in daily life, which is far from the actual life of students. How to present the abstract thing "ton" in front of students with a concrete and perceptible image, so as to narrow the distance between "ton" and students. Therefore, when I design, I fully consider the reality of students' lives and choose things from what students are familiar with and can feel. For example: 3 buffaloes, 10 barrel of oil, 20 bags of flour, 40 people, using students' existing life experience and the conditions available in the classroom to perceive and experience one ton. Combine the content of teaching materials with life scenes, and make mathematics knowledge a reality that students can see, touch and hear. Teachers should be good at digging life scenes in mathematics content and making mathematics close to life, so that students can truly understand the mystery of mathematical principles, that is, their understanding of life. Life is interesting, but math is more interesting.

Second, independent exploration, hands-on practice and cooperative communication are important learning methods.

According to the spirit of curriculum reform, self-exploration, hands-on practice and cooperative communication are more advocated learning methods, so in this class, I gradually let students feel the weight of 1 ton through lifting, calculating and reasoning. At the same time, in every link, I attach importance to let students cooperate and communicate on the basis of independent exploration, and promote the interactive communication between students and teachers and students.

In a word, mathematics practice should be closely linked with life, guide students to apply mathematics knowledge to students' real life to experience feelings, and make students fully realize that mathematics comes from life, which is the basic tool to solve life problems, so as to achieve the purpose of activating mathematics practitioners.