太阳回归运动与晨昏线之变化在初、高中地理中均有涉及,但不能直接演示其变化之规律性。为解决这一问题,我在教学过程中,试做了“太阳回归运动与晨昏线变化”的演示教具。通过它学生可直观地看到太阳位移与晨昏线变化的关系,特别是表明了其渐变的规律性。同时还可解释其他有关问题,教学效果良好。结构:此仪由上盘(动盘)与下盘(定盘)两部分组成。上盘为透明盘,一半为白色,表示白昼,边缘绘出太阳高度角标;另一半淡蓝色,表示黑夜。交界线深蓝色,表示晨昏线。下盘绘出南北回归线与南北极圈,及地轴、极点。将上下两盘的晨昏 Changes in the returning movement of the sun and the twilight line are involved in the geography of the primary and high schools, but they cannot directly demonstrate the regularity of the changes. To solve this problem, in the course of teaching, I tried to do a demonstration teaching aid of “The return of the sun to the sun and the twilight line.” Through it, students can intuitively see the relationship between the sun’s displacement and the change of the twilight line, and in particular, indicate the regularity of its gradual change. At the same time, other related issues can also be explained and teaching results are good. Structure: This instrument consists of two parts: the upper plate (move plate) and the lower plate (set plate). The upper plate is a transparent plate, half of which is white, indicating daylight, the sun’s elevation mark is drawn on the edge, and the other half is light blue, indicating the night. The junction line is dark blue and indicates the dawning line. In the lower plate, we draw the South-North Tropics and the South-North Arctic Circle, and the Earth’s axis and poles. The morning and evening of two plates