Question

You are walking on a long bridge when you look in front of you why does the bridge seem to become narrow? And where does the bridge vanish?

Answer 1

In order to explain the above statement, we will use various factor such as how distance affects the vision and we will also use the example of sun and moon so as to clearing all the aspect the statement and hence we will get them to the conclusion why bridge seems narrow

Complete step by step answer:
In the question we are asked why the bridges become narrow when we look at them from the front and why sometimes it seems like the bridge has vanished. This statement given in the question can be explained by the two reasons: large distance and angular field visio.
Large distance – As the distance between our eyes is very large so the bridge tends to be smaller more, we go far from the bridge more it becomes smaller
Example – it seems from the earth that moon and sun are very small as we know this is not the fact it is only because they are far away from earth so they tends to be smaller
Angular field - human eyes have limitations so it can see up to a limit and this limit is also to extend the angle till which our left and right eye can see so because of the limit of eyes we cannot see bridges that is why it seems to have vanished.

Note:
Many of the people will may confuse between till what extend human eye can see so according to the experiments human eyes have the angular field view of 120 degrees so we can only cover the 120 degrees out of 360 degree at the moment of time happening around our surrounding