"Possibility" is the content of Unit 10 in Book 4 of the math textbook. The teaching goal of this course is "to let students initially experience that some events are certain and some are uncertain", so that students can initially feel and realize that probability knowledge exists in daily life. For primary school students, learning probability knowledge is mainly intuitive. In teaching, students should observe and experiment more, practice and experience by themselves, and get the intuitive feeling of certainty and uncertainty in the game. Thus, useful basic knowledge of probability can be obtained, which can be used to explain life phenomena, analyze problems more comprehensively, and lay the foundation for making some simple judgments and reasoning.
I made a positive attempt on how to embody the new concept of new curriculum reform in the process of classroom teaching. Specific practices are as follows:
First, the game stimulates and introduces dialogue.
Students, what do you think this is? Today, these little crabs are going to have a running race. They are all ambitious and want to win. Listen! Who can win the first prize? (speaking personally) What about another round?
Yes, every crab may win in different competitions. It's possible. (blackboard writing: possibility) in this lesson, we will use our hands and brains to experience possibility.
Second, the activity experience, independent inquiry
(A) teachers and students * * * experience "sure" and "impossible"
1, let's play a game of touching the ball first: (show me a box full of pink balls)
Teacher: I have a mysterious box with some colored balls in it. What color will they be? Who will touch one for everyone to see? (Name comes first)
(1) Can you guess what color ball he may have touched?
Can you tell me what color you might find? (Shake it, don't peek)
(3) I also want to guess that what you touch must be pink. Give me some encouragement.
(4) Who wants to touch it? What color can you touch?
(5) I guess it must still be pink.
(6) Who wants to try?
Do you know the little secret in this box? (Name) Do you want to verify (one shot at a time)
Summary: As you said, this box is full of pink balls. If you touch any one, it must be a pink ball. (blackboard writing: definitely)
2. Teacher: Is it possible to touch the yellow ball you just mentioned in this box full of pink balls? Why?
Summary: Yes, because there are no yellow balls in this box, it is impossible to meet any yellow ones. (blackboard writing: impossible)
(B) group cooperation, experience the "possible"
Teacher: When we were touching the ball, several children were also touching the ball to see how they touched it. (video)
Teacher: Do you understand? What should I pay attention to when playing this game?
Can't peek (when playing games for a while, everyone will be supervisors, and they can't peek at each other. )
And the result? The team leader should make a good record. If you touch the red ball, make a mark on it. ...
Can't wait, there is such a box on the team leader's seat. Please take it out quietly and touch the ball in order under the leadership of the team leader. Please fill in the results in the form 1. (Group activities)
Teacher: Let's count how many times your group touched the pink ball and the yellow ball (according to the group).
Teacher: Observe the number of times each group touches the pink ball and the yellow ball. What did you find?
The whole class touched the pink ball and the yellow ball several times. Let's do the math together.
Teacher: Our class touched the pink ball … times, only the yellow ball … times. How do you think?
Teacher: How many balls of two colors are there in the box? Do you want to know? Please take out the balls and count them. (3 powder 1 yellow) Put the ball in the box.
Summary: Our classmates were really good just now. There are many pink balls in the box, so we touch the pink balls more often, so we say it is more likely to touch the pink balls (blackboard writing).
On the contrary: if the number of yellow balls is small, the number of touches will be less, so it is unlikely to touch the yellow balls. (blackboard writing)
Teacher: Please think about it. There are 65,438+00 pink balls and 65,438+0 yellow balls in the box. How many times will you touch the pink ball? What are the chances of touching the pink ball?
What if there are 20 pink balls and yellow balls or 1?
What if the box is full of pink balls?
Teacher: Imagine boldly, if there were as many pink balls and yellow balls in the box, how many times would you touch them?
Teacher: Are you right? Let's verify it. verify
Please put the same number of pink and yellow balls in the box, which can be 2 pink and 2 yellow, or 1 pink and 1 yellow. Where are the extra balls? Record the results of touching the ball in table 2 (group activities)
Teacher: Observe the number of times each group touches the ball. Which group touches the ball closer? Look at the results. What are you going to say? Count the number of times the class touches the ball. The whole class touched the pink ball … times and the yellow ball … times. What are you talking about? Is it very different from what you just recorded?
Summary: When the number of pink balls and yellow balls is the same, the number of times we touch the balls of two colors is very similar, and the possibility is also similar.
Third, contact life and learn to use life.
1. In our daily life, there are also many possibilities. Some things are inevitable, some things are impossible, and some things are uncertain. Let's do a little exercise.
2. There are many such examples. Can you talk about it?
In this class, everyone can use their brains and learn new knowledge. Who is the cleverest and the fastest? I want to do a little test with the flag. Who wants to take this test? Please take out the flag quickly.
Summary: It seems that your reaction is quick and your ability to reflect is very strong.
Fourth, the class summarizes.
In this lesson, we learned the possibility by touching the ball. In fact, many things in life are possible. I hope you can think hard in your study and find more math problems in your life.
Reflection after class:
In the teaching of this class, a "game situation of connection and development" was created, which enabled all students to complete the learning tasks of experimental exploration and application in an orderly and effective manner in a curious and interesting emotional experience. After class, I reflected on my success or failure:
1, I think practice is the best teacher for students, and what students have learned in practical activities will often be deeply remembered. Therefore, in this class, I create situations such as small crab race and mysterious box to arouse students' interest in learning; In various forms of activities, let students personally participate in the practical activities of touching the ball. Only in this way can students' thinking be unfolded and problems can be naturally discovered and solved by students.
2. The time distribution in the class is reasonable, the students participate in a wide range, the breadth and depth of the game are in line with the characteristics of the students, and the atmosphere of the class is active, which can reflect the students' dominant position.
3. Although it is a practical activity class, it is necessary to infiltrate mathematical thinking methods. It is easier to calculate the number of times the whole class touches balls of two colors.
When teachers and students touched the ball together for the first time, some methods of touching the ball were infiltrated: shake it, don't peek. It laid the foundation for later group exercises.
4. Respect and trust every student, and give them enough space to explore.
Of course, there are also some problems in the process of activities:
1, listening to students is not patient enough, sometimes.