Preschool children have been able to distinguish the size of objects and make a preliminary weight comparison, but they can't distinguish the weight of objects with similar weight. They must be taught the necessity of measuring the weight of objects with tools. Children have accumulated some perceptual experience in comparing weight, but there is no systematic understanding of which methods can be used to compare weight. Therefore, the task of this lesson is to let children learn several basic methods of comparing weights and get a preliminary understanding of weight transfer.

Second, the activity objectives

1. Knowledge target

(1) Through practical activities, let children realize that it is necessary to use tools to determine the weight of an object when it is impossible to accurately compare the weight of the object only by looking at and weighing it.

(2) Being able to sort the objects in positive and negative order according to the different degrees of severity, initially understanding the transitivity and duality between the objects arranged by items, and developing children's judgment and thinking ability.

2. Ability objectives

(1) Encourage children to actively find ways to cultivate their observation ability, practical operation ability and problem-solving ability.

(2) Initially cultivate children's reasoning ability, infiltrate the idea of equivalent replacement, and sort the positive and negative according to the weight difference.

3. Emotion, attitude and values.

Cultivate children's good habit of careful observation and enhance their awareness of experiencing mathematics in practical activities.

Third, the focus of teaching: let children initially perceive the meaning of "light" and "heavy", and let them know some basic methods of comparison through observation, comparison and thinking.

Fourth, activity preparation

Multimedia courseware, objects (books, stones, cotton, elephants, puppies, birds, scales, etc. ), etc.

Verb (abbreviation of verb) activity process

Beginning part

First, create a situation, initially perceive the severity, and learn the method of "taking a look".

1. Play the video of animal activities in the zoo, which leads to important topics.

Question: Which animals are heavier? Which animals are light?

2. Summary: The above methods are more important "take a look" methods.

3. Question: Who can tell who is lighter and heavier than the objects around you?

(1). Children observe and answer questions and find relevant mathematical information.

Show me a bag of cotton and a stone.

(3) Children's further perception of the method of perceiving weight through the shape of objects.

(4) When we can't judge the severity from the appearance, we still use the method of "taking a look" to judge the severity, and create vivid scenes from "asking me to learn" to "I want to learn" according to the age and psychological characteristics of preschool children. And from the animal world back to real life, understand that "weight" is everywhere, and mathematics is around us.

Second, practice and develop cognition.

(A) learn to use the method of "weighing" to compare weights;

1. If you think cotton is heavy, please raise your hand. If you think these stones are heavy, please raise your hand. Why do people have different judgments? Is there any way to prove who is right? Let the children come up and weigh them by hand, and then tell everyone what you found.

2. Teacher's summary: Cotton and stone can't be judged accurately with eyes. We can compare who is lighter and who is heavier by weighing.

Writing on the blackboard: It is more important to use "point one".

(2). Learn to compare weights by "weighing";

1. Display 1 carrot and 1 potato, with similar weights.

2. Guess: Who is lighter or heavier?

Take a look: who is lighter and who is heavier?

Teacher: Whether you guess or weigh, the children's answers are different. What shall we do? Who can come up with a good idea?

3. Summarize the discussion: What method can you come up with?

4. Show the balance and introduce the method of weighing on the balance. The teacher put carrots and potatoes on both sides of the scale for the children to observe. Now you know who is lighter and who is heavier?

5. Group activities.

Take out the things around you, choose two, guess first, then weigh, then weigh, and say who is lighter or heavier.

6. Teacher's summary: From the comparison of carrots and potatoes, we find that weighing is the best way to know exactly who is lighter and who is heavier.

7. Show me the pencil-box and calculation book.

Let's talk about it first: who is lighter and who is heavier? Why?

Weigh it again.

Clear: more important. You can't just look at the size, the big one is not necessarily heavy, and the small one is not necessarily light. We must really weigh it before we can determine who is lighter and who is heavier.

Health 1: the pencil case is light and the calculation book is heavy;

Student 2: the calculation book is light and the pencil box is heavy;

Health 3: The pencil case is as heavy as the calculation book.

The conclusion is that the pencil box on the desk is heavier than the calculation book.

Draw a conclusion: the pencil box on the desk is lighter than the calculation book.

Children's experiments, exchange discussions and guess the results.

Report and exchange, fully listen to the different methods that students come up with, and give appropriate evaluation.

Guess in groups, weigh again, and finally weigh, and talk about who is lighter and who is heavier, so as to understand that the weight is relative.

(3) Take a look: Look at the picture and decide who is the lightest, the elephant, the dog or the bird? Who is the heaviest? Understand the heredity of weight.

(4) Think about it: Let the children compare who is lighter and heavier than a boat and a stone. Why can a boat float on the water and a stone sink to the bottom?

(5) Arrange in a row: Please arrange the objects in positive and negative order according to the rules from light to heavy and from heavy to light, so as to consolidate children's cognition of light and heavy.

Third, consolidate practice and deepen familiarity.

1. By comparison, children do it independently. Tell me how to judge.

2. Say, let the children finish it independently first, and then guide them to tell who is the heaviest? Who is the lightest? Why?

3. Extend, explain the story of "stupid donkey" and sublimate knowledge points.

Sixth, reflection activities.

1, following the principle of learning from simplicity to complexity and step by step, through "taking a look" and "weighing",

More important "weighing" method. During the activity, I drew many conclusions and realized the joy of inquiry. Activities run through the whole class, so that children have always maintained the passion to participate. Finally, the story of "stupid donkey" is thought-provoking, which makes children think fully and is the sublimation of knowledge.

2. Give full play to children's subjectivity in teaching, and let children learn to "look" and compare in observation.

Methods; Learn to "weigh" more important methods through inquiry and collaborative activities in personal experience; Learn the method of "weighing" in inquiry and reasoning. In teaching, paying attention to physical objects can stimulate children's interest in learning from a variety of senses, so that children can actively learn knowledge in happiness.

3. Let children study math alone. Mathematics learning should be a lively, active and personalized process. In this class, children dare to ask questions, can ask questions, and solve problems with their own unique opinions, and their personalities have been fully publicized. Students are happy for their own creation and excited for their own discovery. At the same time, I also pay attention to using inspiring language to evaluate their performance, so that they can get a positive emotional experience.

In short, in the whole classroom activities, students should be the main body and let them think, say and do. It is necessary to "squat down and look at the children" and "look at the problems from the children's point of view". It is necessary to affirm all the efforts of children in teaching, praise their thinking conclusions and stimulate their creative desire.

Finally, I also realize that I have many shortcomings, such as sometimes not paying attention to catching the sparks of students' thinking. I will study with my children and make progress together in the future.