What are the causes of the four seasons?

It is not easy for students to construct a correct explanation about the causes of the four seasons in their minds. In this lesson, I will let the students make full guesses and arguments by using the stick shadow according to the known earth movement mode and the research results of the ancients on the causes of the four seasons. Students' preconceptions are as follows: each side of the sun emits different light and heat. The earth turns to the side with more heat, enters summer, turns to the side with less heat, and enters winter; The orbit of the earth's revolution is elliptical. It's summer when it's close to the sun, and winter when it's far from the sun ... but they feel that they can't cope with the change of the polar shadow, and their thinking is in a dilemma. At this time, guide students to carry out simulation experiments, emphasizing that the inclination and direction of the earth axis remain unchanged when the earth rotates, and see what happens to the shadow length when the pins standing in the northern hemisphere revolve to four o'clock A, B, C and D, and judge the four seasons according to the shadow length. After such a process, the students went through a process of thinking and found out the causes of the four seasons step by step. When all the phenomena and evidence were finally linked, I was happy to see the bright smiling faces of the children.