某一点的地理坐标是我们认识该点在地球表面相对位置的重要参数,是中学地理教学的基础内容之一。笔者曾带领高一地理实践组进行了经度实地测量,得到了具有较高精度的结果。如何用我们现有的简单测量器材进行宏观的测量呢?在学习地球自转对地理环境影响时,我们已经了解到经度与地方时之间有着必然联系,那么,我们就有了测量的思路:通过测定某地正午时刻的北京时间推算出该地经度。因此,关键就成了如何测量当地正午时刻的北京时间。为了让这一活动变成学生自己的活动,我让学生自己设计方案,但必须达到以下两个 The geographical coordinates of a point is an important parameter for understanding the relative position of the point on the earth’s surface and is one of the basic contents of geography teaching in middle school. The author once led the high geography practice group to carry on the longitude field survey, got the result with higher accuracy. How can we measure macroscopically with our existing simple measuring instruments? When learning the influence of the Earth’s rotation on the geographical environment, we have learned that there is a necessary relationship between the longitude and the local time. Then we have the idea of ​​measuring Beijing time to determine a noon time to calculate the longitude of the place. Therefore, the key has become how to measure the local noon time Beijing time. In order for this activity to become a student’s own activity, I let the students design their own programs, but must achieve the following two