Activity objectives:
1, cognitive goal: understand the meaning of dichotomy and learn dichotomy.
2. Operation goal: Explore different ways to divide the graph equally through operation, and experience the inclusive relationship and equal relationship in the equal division.
3. Educate children to develop a good habit of doing things seriously and not being careless.
4. Cultivate children's politeness and love of labor.
Divergent point:
Divide the graph equally with different bisectors.
Activity preparation:
Several square colored pieces of paper, multi-operation learning tools, several chessboards, recording paper, scissors, pencils and hand puppets.
Activity flow:
(1) Average distribution figure
1, on-site introduction. Combining the age characteristics of large-class children, creating this problem situation can not only attract children to participate in activities, but also show the mathematics of life more vividly and make it easier for children to understand.
(1) Show your puppet: "Who do you think is here?" Child: "It's Sister Ping."
(2) When performing the puppet, the teacher asked, "Why is Sister Pingping unhappy today? Is there any trouble? " Pingping (teacher): "I had breakfast this morning. I found there was only one piece of bread, but I wanted to share it with Yingying. Son, please help me think about what I should do? "
(3) Teacher: "Who has a good idea?" Child: "Just divide the bread into two parts!" "
(4) Pingping (teacher plays): "But there will be big and small after the points are finished. What should I do? "
(5) The teacher showed a square piece of colored paper and asked, "What shape is this piece of bread?" Child: "Fang." Teacher: "Then let's use square paper instead of bread and help Sister Ping divide it into two pieces of the same size!" " "
2. Provide children with square paper and scissors and ask them to operate. Give children the opportunity to try and verify their own ideas, and you can try all kinds of dichotomies indefinitely. Cut it open with scissors, so that children can verify whether the two parts are equal.
3. Summary:
(1) Teacher: "What shapes did you divide the square into? How do you divide it? "
(2) Teacher: "There are several ways to divide" (diagonally folded in half)
(3) Teacher: "How to prove that these two pieces are the same size?" (one-on-one)
(4) Teacher: "How can we be as big?"
(5) Teacher and child summary: As long as you find the center line, you can divide one into two equally big ones. Further guide children to master the key points of bisection.
(2) Further exploration with learning tools.
Only paper is used for dividing, which is caused by the age characteristics of children at this stage. There are only two accurate bisection methods: diagonal and folding. Using learning tools and grasping the characteristics of learning with holes and holes, children can further try to bisect a square with various broken lines as the center line, and the accuracy can be guaranteed. Promoting the development of children's divergent thinking is a variety of methods for children to freely try dichotomy on the basis of clear requirements for dichotomy. This link pays more attention to children's creativity and uniqueness, and it also permeates a truth: there are many ways to solve one thing.
1, teacher: "You used two methods. Is there any other method?"
2. Ask children to try with school tools, and accurately find the center lines of different shapes, and explore inspection methods. Inspection can prove that the two parts have the same size and the inspection method is not single. The purpose of putting the same homework sheet for children as a proofreading board is to record the equal division method and cut the recorded homework sheet for comparison and proof. In addition to this method, we can also compare whether the number of holes in each row on both sides of the bisector is the same.
3, children's grouping operation, teachers look for different center lines and inspection methods for guidance, and guide children to record and test.
4. Summary: Show your child's homework list. Who can tell me how you divide them equally and how you guide them to be the same size? Ask children to introduce innovations to other children and show different ways to test equality. Let children have the opportunity to communicate and show, and encourage children to innovate in combination with the characteristics of collective learning of large class children.
Activity reflection:
Through operation, exploration, observation and comparison, we can master dichotomy, guide children to learn and explore from shallow to deep, learn to think from different angles and directions, solve simple mathematical problems through observation, comparison, analogy and migration, and cultivate children's interest in mathematical activities.