Teaching goal of "balance of interest" teaching plan design
1, the students found through the experiment of life balance phenomenon? The number of scales on the left? Number of scales = number of scales on the right? Number of scales? The initial feeling of this law is the lever principle. When did you find it? The number of scales on the left? Number of scales? When they are the same, what are the scales on the right? With what? Number of scales? In inverse proportion, deepen the understanding of inverse proportion.
2. Through the review and excavation of life experience, I realize that balance is related to quality and distance, which cultivates the thoroughness and comprehensiveness of thinking. Seek laws through experiments, cultivate abstract generalization ability, accumulate hands-on experimental experience and enrich activity experience.
3. Through the process of mathematicization, cultivate students' habit of looking at life phenomena around them from a mathematical perspective. Through group cooperation and sharing, students can broaden their thinking horizons, feel differences and enrich their learning experience.
teaching process
First, feel the factors that affect balance.
1. Teacher: Please look at the big screen. What kind of phenomenon do these two pictures reflect together?
2. Teacher: Can you tell me according to your past life experience: Is balance related to anything?
(quality) (blackboard writing)
What else is balance related to?
Health: Balance is also related to distance. (blackboard writing: distance)
Teacher: So, what kind of mathematical laws do mass and distance contain in the balance? In this lesson, we will learn "interesting balance". (blackboard writing topic)
Let's carry out the activities in groups. Please take a look at the preparation and explanation of the activity first (show it on the big screen and then mark the number of books on the blackboard below the distance and quality). Then look at the activity requirements (big screen display). Knowing the relevant requirements of the activity, we started the activity. Please start with the first activity.
Second, explore the law and understand the principle of leverage.
1, activity 1: Explore the law of keeping the balance of meters and feet under special conditions.
(1) Media presents questions to explore:
① If the hook code is hung on the same scale on the left and right sides of the instrument scale, how to put the hook code to keep balance?
② If you put the same number of hook codes on the left and right, where can they move to keep balance?
③ The law of discovery is: _ _ _ _
Exploration method: group cooperation and clear division of labor.
(2) Group report.
(3) Teachers guide students to generalize laws.
Put the same number of hook codes on the left and right sides of the same scale, and the meter scale can be balanced.
(4) Tutor demonstration and verification.
2. Activity 2: Explore the law of maintaining the balance of instrument scale in general.
(1) Media presents questions to explore:
① If you put four hook codes on the left scale 3 of the rice scale, how many hook codes can you put on the right scale 4 of the rice scale to balance it?
② If 1 hook code is placed on the left scale 6 of the meter scale, how many hook codes are placed on the right scale 3 of the meter scale? What about on scale 2?
What have you found?
Exploration method: group cooperation and clear division of labor.
(2) Group report. (The lecturer shows the report data on the big screen)
(3) Teacher: Please recall whether our first experimental conclusion also conforms to this law. (health report)
(4) Demonstration and verification by the tutor.
(5) Teachers guide students to sum up the rules again. Parallel blackboard writing
Left scale number? Number of scales = number of scales on the right? Hook code number
(6) Teacher's summary: The law discovered by students actually lies in physics? Lever principle? The point where the rope is tied is the fulcrum.
3. Activity 3: The students got the law of balance through the operation just now. Next, please think about it according to the law of balance:
(1) Question: Put three pieces on the left scale 4, and keep it unchanged. How many pieces can be balanced on each scale on the right? Tell me what you think.
Blackboard writing: put 3 pieces on the left scale 4 and keep it unchanged.
Scale on the right: 1 2 3 4 6
The corresponding number of chess pieces: _ _ _ _ _ (12, 6, 4, 3, 2)
(2) Students do experimental verification.
Students, is this law of balance that you summarized scientific and accurate? We need to do further verification. Let's actually verify whether the hook code you put on the right scale keeps the balance of the meter scale.
(3) Teacher's summary: Through the verification just now, we found that the number of hook codes we put on the right is correct. Then, please think about it: what is the relationship between the number of scales on the right and the number of hook codes when the product of the number of scales on the left is unchanged? (Inverse relationship) (conclusion is displayed on the big screen)
Expansion and extension
Activity 4: Hang several pieces with different scales at both ends of the rice scale to explore the law of maintaining balance.
Teacher: The students found a lot in the experiment just now. You're amazing! Let's add some difficulty. Just now, we put a tick on a scale on the left and right sides of the iron bar and summed up this law of balance. If we tick multiple scales on the left and right sides of the iron bar, does it still conform to this law? This time, we are still trying to find a conclusion through experiments.
(1) The experimental contents are displayed on the big screen.
(2) Students experiment in groups. (Instructor's guide)
(3) Teacher: Which group of students would like to share your group's findings with you? (health report)
(4) Teacher: Can you say that this rule is true only by your experimental conclusion? More verification is needed. There are so many people in class that the teacher wants to show it. Do you agree?
Ask the teacher to check the problem.
(5) The teachers and students are the same as the verification.
(6) Teacher: Different experimental data have reached the same conclusion, which shows that this rule is correct. In fact, this is a law that has been scientifically verified. I hope the students can understand it in combination with their own operations.
Show courseware: the sum of the products of left tick and scale number is equal to the sum of the products of right tick and scale number.
Fourth, connect with life, apply what you have learned and solve practical problems.
1. In fact, balance has many applications in our life. Who can tell us other examples of balance in life? (health report)
Everyone is right. Let's see how a balance is used to weigh the mass of an object. Teach the principle of scale on the big screen.
We have understood the law of balance and its application in life. Let's use the law of balance to solve this problem.
(1) On Sunday, my father took Xiaoming and his sister to the park to play on the seesaw. Xiao Ming weighs 44 kilograms and his sister weighs 35 kilograms. How many ways can you at least think of if you want to balance the two sides of the seesaw?
Mother and daughter are playing on the seesaw. Daughter's weight 12kg, sitting away from fulcrum 15km. Mother weighs 60 kilograms. How far can she sit from the fulcrum to keep the balance of the seesaw?
(3) The vegetable vendor is dishonest. His balance has been tampered with. The two arms of this balance are unequal in length. One day, he bought a cabbage with an actual weight of 5 kg from a farmer and put it on the shorter side of the balance arm, which was lighter. The balance showed that it weighed only 4 kg. When he sells cabbage, he puts it on the longer side of the balance arm, so how much does it weigh?
Class summary: Today, we learned about the lever principle by doing interesting balance experiments. In the future, we should be good at discovering mathematical problems in life, look at life from a mathematical perspective, and then use what we have learned to solve problems in life. In fact, many phenomena in life, if viewed from a mathematical point of view, will bring us more interesting thinking.
"Interesting Balance" Teaching Plan Design II Activity Objective:
1. In the interaction with materials, feel the relationship between balance and the weight and placement of objects.
2. Look for different ways to keep the balance of objects in combination with life scenes.
Activity preparation:
1. Balance toys: balance scales, moon boats, balance frames, eagle toys, balancers and accessories.
2. Create the life scene of the doll house and the acrobatic troupe, and prepare clothes hangers, clothes, socks, rulers, books, balls, forks, building blocks, balance boards, rice, containers, radish pieces, potato pieces, sticks, bowls and pots.
Activity flow:
One: Play with balanced toys and feel the phenomenon of balance.
t:？ Come and see: there are many toys here. Look, there are moon boats, swings, seesaws and so many toys. Do you want to play? I want to play too. Tell you, when we play together, we can use our brains while playing, and then tell you our new findings.
T: Let's go! ?
(Prepare all kinds of balance toys)
1. Children operate and play with balanced toys in groups, and teachers participate in children's exploration process.
2. Share communication, encourage children to speak out their findings and problems boldly, and help children improve their key points. (For example, the relationship between balance and weight and placement position. )
T: I heard that many children have made new discoveries. Let's hear it!
Second: try to keep the object in balance.
T: Just now, we discovered many little secrets of balance. In fact, there are many things in our lives. As long as you use your little brain, you can balance them. Today we will go to the Dollhouse and Acrobatic Troupe, give it a try and find it! See if there are any good ways to keep the content balanced. Have confidence? Jean? Let's go
1. Children explore ways to balance objects in groups, and teachers observe and guide them.
2. share communication.
According to children's experience, several methods of balancing objects are summarized. (Can be popularized: by increasing the weight of one side or reducing the weight of one side, find a balance point or move the distance of one side, etc. )
Today, you are great. You found a good way to balance objects, and you recorded all these good methods. Then, let's make the recording paper into a balanced record book and put it in the reference room to let more friends know the secret of balance, shall we?
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