"How much is 1 ton" is the knowledge of Unit 3 in the first volume of the third grade textbook published by Beijing Normal University. Before teaching, students have a perceptual knowledge of the quality units "gram" and "kilogram", and the progress rate of students on 1 kg =1000g is also clear. They can use what unit to express the quality of heavy objects or bulk goods in their lives, or they can use "tons" as the unit, but students have no perceptual knowledge of how much 1 ton is. The textbook only uses three 350kg cows, 10 barrel 100kg oil and 20 bags of 50kg flour to illustrate. If we follow this mode of teaching, students can understand the weight of 1 ton, but they lack the process of experience and perception. It's hard to say that they really know the weight of 1 ton. To solve this difficulty, we need to design some familiar life examples, give students a certain experience, experience and perception process, and let them really understand the weight of 1 ton.

Based on the above thinking, I designed a back-to-back experience to find some students weighing 25 kilograms. I asked some students in my class to try to recite this 25 kg student to see who can recite more than one student. The enthusiasm of the students is very high. Some students can carry a 25 kg classmate, while others can carry one and hold one at the same time. Everyone feels the joy of experience through laughter and shouts. Ask them what a student of 25 kg 1000 kg is, that is, () tons, and the students quickly give the answer. Then, I "use the topic to play", let the boys or girls before and after tell each other their own weight, and then recite each other, and estimate how much XX weighs a ton.

After the teaching, I noticed that the students were in high spirits and focused. This shows that students like this experience very much. Through the experience, they can further deepen their multiple perceptual knowledge of 1 ton, thus breaking through the teaching difficulties.