Huizhou 11 th primary school yangruier
[Design concept]
Gram and kilogram are a brand-new quality concept for grade two pupils. According to students' psychological characteristics, age characteristics and real life experience, in classroom design, students can see, say and do through practical activities such as weighing, comparing, estimating and weighing, and emphasize the participation of various senses, so that students can establish the quality concepts of 1g and 1kg from different angles and understand grams. And apply what you have learned in animated stories to realize the value of knowledge.
[Teaching content]
Compulsory Education Curriculum Standard Experimental Textbook (People's Education Edition) Unit 6 "Grams and Kilograms" in the second volume of Grade Two Mathematics.
[Teaching objectives]
1. In specific life situations, let students feel and know the unit grams and kilograms of quality, and initially establish the concepts of 1g and 1kg, knowing that 1kg = 1000g.
2. On the basis of establishing the concept of quality, cultivate students' awareness of estimating the quality of objects.
3. Through operation and observation, let students know how to use the scale, cultivate their ability to operate and solve problems, and enhance their sense of life.
[Teaching aid preparation]
Multimedia courseware, new edition 1 dime, 6 bags 1 kg rice, 6 bags of 200 g red beans, 6 bags of 500 g peanuts, 6 bags of 2 kg sand, 6 apples, 6 bags 100 g, 200 g, 500 g, 800 g sand, and 6 sets of board scales.
[Teaching process]
First, preparation before class
Students go to the supermarket to investigate the weight of goods and complete the table below.
The name of the object is called the weight of the object.
Second, introduce from life
Teacher: A few days ago, students went to the supermarket to investigate the weight of common items in our daily life. What did you get from the investigation?
Health 1: I know that a bag of candy weighs 400 grams.
Health 2: Found a packet of instant noodles 105g.
Health 3: A bag of household washing powder is 3 kg.
……
Teacher: The "gram" and "kilogram" that the students read just now are international weight units. (blackboard writing: grams and kilograms)
Second, learn in life.
1, know the scale.
(1) Teacher: How do you know the weight of these items?
Health: Look directly at the weight marked on the packaging bag.
Teacher: This method is good, but many items have no packaging bags, such as eggs, apples and other items. What should I do if I know their weight?
Health: You can weigh it with a scale.
Teacher: Yes, if you want to know the exact weight of an item, you can weigh it with a scale. Which scales have you seen in your life?
(2) Students can freely talk about common scales in life. The teacher's courseware shows and introduces the common scales in life.
(3) Introduce the usage of the scale in detail (courseware display)
A. Observe the scale surface and tell me what is on the scale surface.
B, introduce how to divide the scale into large cells and small cells, and how many grams they represent.
C, know the scale practice. Say the grams of the weight on the scale shown in the courseware.
2. Establish the concepts of "gram" and "kilogram".
(1) Teacher: After investigation, students all know that "gram" and "kilogram" are used to express the weight of an object, so what is 1 gram? (blackboard: 1g)
(2) Ask students to use 1 cent to weigh 1 coin. How do you feel?
(3) For example, what items in daily life weigh about 1 g?
(4) Teacher: What is 1 kg? (blackboard writing: 1kg)
(5) Ask students to weigh 1 bag 1 kg of rice and compare it with 1 cent/coin. How do you feel?
(6) Weigh 1kg rice, observe the change of the pointer on the scale, and mark it on the scale.
3. The relationship between "gram" and "kilogram".
Teacher: "kilogram" and "gram" are two different units of mass, so how many 1 kilogram will be 1 gram? Let's do an experiment. Different grams of sand are marked here. One representative of each group will take the goods and put them on the scale, so that their weight is exactly 1 kg. Then add up the weights marked on the bags to complete the record sheet. Tell me what you found.
Weight and quantity of each package
100g package
200g bag
500 grams a bag
800g bag
Total weight gram
Teacher: What did you find from the above experiment? (blackboard writing: 1kg = 1000g)
4. Summary: We use "grams" as the unit for lighter items and "kilograms" as the unit for heavier items.
Third, practice in life.
Teacher: Please weigh each child and estimate the weight of this bag of red beans.
(Student activities)
Teacher: How much do you weigh this bag of red beans in groups?
Health: 200 grams.
Teacher: Please check the weight of this bag of peanuts again.
(Student activities)
Teacher: What's the weight of this bag of peanuts again?
Health: 500 grams.
Teacher: Would you please weigh this bag of sand again?
(Student activities)
Teacher: How much does this bag of red beans weigh?
Health: 2 kg.
Teacher: 1 How much does the apple weigh? Please weigh the apples before weighing them, and then say how many apples are there 1 kg.
Fourth, application expansion.
Teacher: The teacher brought an animated film "Accompanying Glass" to the students. do you want to see it ?
Animation: On Sunday, Piggy and Smart Dog go to Huahu Restaurant to drink. Piggy accidentally broke Huahu's cup. Huahu wants to knock the pig and ask the pig to accompany him 100 glasses. Facing the broken glass all over the floor, no one can tell how many glasses were broken.
Let the students uphold justice for pigs, speak freely and make suggestions.
Play the animation again: the clever dog came up with a clever idea. Weigh a intact glass (200g) first, then broken glass (1000g).
Ask the students to calculate how many cups the pig should accompany.
Verb (abbreviation of verb) summary after class
What's new in this lesson? How do you feel about learning new knowledge? There is nothing you don't understand.
[after-class reflection]
Gram and kilogram are two unfamiliar and familiar concepts for sophomore students. Before class, I asked my classmates to go to the shopping mall for a practical investigation, which made them feel that mathematics was everywhere around them, and at the same time let them initially establish the quality concept of grams and kilograms. Let the students know the progress speed between grams and kilograms. I didn't tell the students 1kg = 1000g directly, but let them sum up 1kg = 1000g by doing experiments. It fully embodies the process objectives advocated by the new curriculum standards. In the exercise part, students have a deeper understanding of the quality concepts of grams and kilograms by weighing, estimating and weighing, and cultivate their estimation consciousness. At the end of class, I asked students to give advice for piggy, which cultivated students' divergent thinking and problem-solving ability, enhanced students' awareness of life and realized the application value of knowledge.
Students are in an active learning state from beginning to end in a relaxed and happy learning atmosphere. Students turn passivity into initiative and truly become the masters of mathematics learning.