The theme of this lesson is how long a pencil is. The learning tool used in this class is my "straw". They are the uniform unit of length of 10 cm. This is because when preparing lessons. I think it's unrealistic to ask students to estimate a pencil with a length of 10 cm for the first time in textbook design, so I use a homemade straw instead. This not only facilitates the classroom operation, but also saves some unnecessary troubles and saves the classroom learning time more effectively. In this class, I give full play to the role of teachers, creatively use textbooks, and re-create textbooks according to the actual situation of students, so that students can better understand the length of "1 decimeter", and children can easily learn new knowledge, which successfully breaks through a key point of this class, and also reflects that life class should be student-centered and let my class serve children better.
Because the understanding of length units and the establishment of the concept of length space are abstract, students should be given enough time to help them establish the concept of space with the length of 1 decimeter in the activity of understanding how long 1 decimeter is. In the first step, I asked the students to estimate the approximate length of the straw, and then measured it accurately with tools to cultivate students' awareness of estimation and initially perceive 1 decimeter. Step 2, repeatedly compare the length of 1 decimeter with a ruler and a straw, and establish the concept of 1 decimeter length. The third step is to deepen the understanding of the length of 1 decimeter by using articles in life. Then, by pointing out where 1 decimeter, 2 decimeter and 5 decimeter go on the meter scale, students can further understand the length unit decimeter. Students may have different answers in the activities they are looking for, ranging from 0- 10 to 1 decimeter, from 30-40 cm to 1 decimeter, from 15 cm to 25 cm to 1 decimeter, which not only cultivates the sense of numbers, but also creates for students.
When understanding millimeters, the length of students' pencils is different. When students find that it is not necessarily an integer through hands-on measurement, they can have a kind of thinking in their hearts, which needs to be expressed in units less than centimeters, so naturally the length unit millimeter is deduced. In addition, based on the knowledge of "1 decimeter", students can shorten the time when they know millimeters, so as to make the classroom rhythm relaxed.
Mathematics comes from life, and naturally it will eventually return to life. After the children mastered the content of this lesson, I asked them to choose their favorite items to estimate and measure, and apply mathematics knowledge to their lives. This will help children to further cultivate the concept of length, and also make them more interested in mathematics, so that children are willing to learn mathematics, learn mathematics by hand, and learn mathematics in a relaxed and happy atmosphere.
There are still many shortcomings in this class. Although there are many opportunities for children to do it themselves, the class as a whole is still a bit monotonous, so how to better integrate the activities in the class needs my constant exploration.