用数学物理知识分析人眼观察帆船

Utilizing Theories in Math and Physics to Analyze Human Eyes' Observations on a Sailboat

游戏在广阔的水边,常发现水面云帆点点。登高远眺,体会"孤帆远影碧空尽,唯见长江天际流"。全国很多出版社的初中地理课本都以人眼观察帆船为例说明地球是个球体,这一例证已经沿用几十年。但是在多远距离范围内人眼能够看见桅杆?多远距离范围内能够看见船身?多远看见船帆?这其中还存在哪些人们未知的奥妙?本文通过在巢湖水域的亲身观测,发现了大家平时没有注意到的很多奥秘:没有"先见桅杆后见船身";只能看到"先见船身后见桅杆";可以观察到"只见船帆不见船身";站在高处不受地曲影响,则"同时见到船帆和船身"。

While playing at the broad waterside,we often spot that sails like clouds-scattering above the water surface.And while ascending a height to enjoy a distant view,we come to understand the feeling of ＂His lessening sail is lost in the boundless blue sky;where I see but the endless Yangzi River rolling by.＂ In the middle school＇s geography textbook,many publishers have used the observations on a sailboat from human＇s eyes as an example to illustrate that the earth is a globe.And this example has continued to be cited for many years.However,what is the range of the distance for human eye to locate the mast And how that range could be so that people would notice the hull of a boat,or the sail Any more unknown profound theories exist in this nature phenomenon In this article,personal experience at Chaohu Lake water area discovered many secrets that are normally unnoticed.That is,we cannot spot the hull prior to the mast;we can only see the hull ahead of the mast;and we may view the sail without the hull.But when we stand on high,we can see both the sail and the hull as the earth curvature couldn＇t impact our view any more.