In the teaching process, teachers guide students to weigh, weigh, estimate and calculate, and experience the perceptual operation of actual objects, so as to establish the concept of object quality and experience the weights of 1 kg and1g.
Clear and natural in dealing with teaching links. For example, after 1 kg is taught, 1 1 dime is weighed on the platform scale, indicating that the pointer has not moved. The teacher asked: Is it without quality? The students immediately said that 1 1 dime also has quality, but it is very light. Teaching naturally guides students to learn the concept teaching of "Ke".
Understand the application value of mathematical knowledge of kilograms and grams in real life. It is very important and necessary to choose standard materials when teaching the concept of "1 kg". Before class, I prepared two bottles of self-irrigation mineral water weighing 500g each and five apples weighing 1kg. I investigated that the salt in the market is 350 grams per bag. In the absence of multi-party investigation, I asked the students to bring three bags of salt, but the quality of each bag of salt was different, some were 300g, some were 350g, 400g and 450g. The students passed the weighing. For example, three bags of 350 grams of salt were weighed again, and the number displayed on the scale was 1050 grams. The teacher did not adjust the extra 50 grams in time. The concept of student 1 kg is not a standard model.
How to set aside time and space for homework in teaching? How to guide students' practice? For example, weigh and estimate how much a dictionary weighs. Think again when teaching, and teachers should not underestimate students. Students say 500 grams, 600 grams, 1 kg and so on. Teachers can ask students to weigh 1 bottle of 500g mineral water and a dictionary first. Thinking about who is light and who is heavy? Then estimate how much a dictionary weighs. This is targeted. Students can estimate that the number of a dictionary is about 300 grams.
Reflections on the Teaching of Multiplicity in Beijing Normal University Edition
Through teaching, I realize that the teaching of measurement units should not be based on teachers' "speaking" and demonstration, but on students' "doing", so that students can move, experience and feel the formation process of knowledge, and finally summarize and refine it by themselves as a means of knowledge externalization. "Experience" is the key to the teaching of measurement units. Experience refers to the feelings and consciousness produced by physical activities and direct experience. Teaching pays attention to let students feel kilograms in the experience, so as to obtain the tactile representation of "kilogram weight", which is the basis of image thinking. Representation has two characteristics: vividness and generality. How to visualize such an abstract kilogram weight? Students can talk about how they feel after weighing an object weighing 1 kg. They also want students to weigh objects that weigh 1 kg and objects that weigh less than 1 kg by hand to consolidate their appearance in comparison. As for generality, when weighing objects, students can provide objects with different shapes, sizes and materials, so that students can exclude the properties of materials, shapes, sizes, colors and sum up their feelings about weight.
1 ton? The practical meaning of tons is abstract, which is difficult for students to master. Therefore, based on students' existing knowledge and experience, I let students understand that 1 ton = 1000 kg. A concrete example is 1 ton, which is the weight of 40 25 kg children. There are about 20 adults with 1 ton, so there is a picture in the book that mentions the elevator weight limit of 1000 kg and 15 people. There are three reasons for students' understanding of 15 people: 1, the elevator itself has weight. There may be adults and children in the elevator, and there may also be people with heavy weight. 3. For safety reasons, you can only take 15 passengers at most, otherwise it will easily cause accidents. You see, how carefully the students consider it. There are still some examples, which are not listed here. In short, students are interested in learning and teachers are willing to teach.
There are many kinds of teaching reflections.
Today, I'm going to explain how heavy the math class is, so that students can feel and understand the unit of mass of kilograms and grams, and understand the actual mass of 1 kilogram and 1 gram. Master "1 kg = 1000 g" and make simple conversion. Experience the connection between mathematics and real life, and feel that mathematics is around.