夏至日或冬至日当天,白天有多长时间?太阳光线与地平面的夹角为多少度?如何由当地竖杆的影子长度来计算竖杆的高度?这些有趣的问题,与物理、数学和地理知识密切相关,而且可推导出地球昼长公式和正午太阳高度角公式,由公式来计算某地冬至日或夏至日的昼长和正午太阳高度角.冬至和夏至都是农历二十四节气,对于北半球一定纬度处,冬至那天,白天最短,正午太阳高度最小;而夏至那天,白天最长,正午太阳高度最大.过了冬至,北半球白天的日照时间增长,同时太阳直射 How long will the day be during the summer solstice or the winter solstice? What is the angle between the sun’s rays and the ground plane? How to calculate the height of the stanchions from the shadow length of the local stanchions? These interesting questions, related to physics, mathematics and Geographical knowledge is closely related, and can deduce the earth day length formula and midday sun height angle formula, calculated by a formula winter solstice or summer solstice day length and midday sun altitude angle. The winter solstice and the summer solstice are Lunar New Year solar terms , For the northern hemisphere at a certain latitude, the solstice that day, the shortest daytime, midday minimum sun height; and the summer solstice, the longest daytime, midday sun maximum.After the winter solstice, the Northern Hemisphere daylight sunshine time increases, while direct sunlight