Making method of Big Dipper model

The making method of the Big Dipper model is as follows:

Find a square cardboard with a side length of about 50 cm and punch 7 holes according to the figure. Hang 15cm, 12cm, 15cm, 17cm, 27cm, 27cm, 14cm thin iron wires in the No.65438+7 hole, and hang plasticine balls with the same size at the lower end of the thin iron wires.

Illuminate them from the side with the light of the projector and record the shadow of the plasticine ball on the screen. Turn the light source, let the light shine on the model from four different angles, let the shadows of the seven stars completely fall on the screen, trace their shadows, and then connect them with lines.

The Big Dipper consists of seven stars: Shu Tian, Tian Xuan, Tianji, Tianquan, Yuheng, Kaiyang and Yaoguang. These seven stars are shaped like barrels of wine in ancient times, hence the name Big Dipper. The Big Dipper appears in different directions in the sky in different seasons and at different times at night, so the ancients decided the seasons according to the direction pointed by bucket handle at the beginning of fainting: bucket handle refers to the east, and the world is spring; Bucket handle guide, the world is summer; Bucket handle refers to the west, and the world is autumn; The barrel handle refers to the north, and it is winter all over the world.

The Big Dipper is the creator of heaven and earth order. The harvest in spring, summer, autumn and winter storage all follow the direction of bucket handle, and it is also the center of the metaplasia of everything in the world. The Big Dipper will appear in different directions in the northern hemisphere sky in different seasons and at different times at night, so the ancients decided the seasons according to the direction pointed by bucket handle when he first fainted.