B What is the Effect of Normal Lines on Glass Surfaces?

[ExperimentingStudent]

I am a degree student and .. A loner. During my free time, I usually try to observe my surrounding more, you know... :\
Here's the experiment I did (I saved it in my note app, copied it directly from there):

A certain window has a point of view (not referring to the meaning where point of view means opinion)
Just perform these steps:

1. Place your index finger on the window, PERPENDICULAR to the window surface.
2. Then position your head just behind your finger which is perpendicular to the window.
3. Now watch from that view (exactly from the straight view of your index finger)
4. Note (or remember) the place to which your Index finger points to.
5. Repeat the above 4 steps by placing your index finger on different points on the same window.

I would appreciate anyone's explanation based on my (or if you performed this then yours) explanation.
Thank you.

 

[Merlin3189]

I think you need to tell us what it is that needs explaining.

We have the method, but not the results nor conclusions. (We'll ignore the object!)

 

[Drakkith]

Explanation of what? You haven't told us what you've observed so that we know what to look for.

 

[ExperimentingStudent]

Sorry, I guess the correct term I should have used was "line of sight". Would have made this a bit more understandable maybe.
Anyway, let me explain this more.

I chose 4 points on any window in my house.

The first image (edit: *re-uploaded* this is last image now, please return to the starting image right after the very last one) indicates the 4 points on the window I chose to perform this small experiment.
The order of following 4 images are:
1,4,3,2.
The digits above is the order of the points I placed my finger on.

Okay now,
Observe the next four images after the very first one (in which the points are indicated).

The only thing you have to look carefully at is the white lamp post position which is almost same for all the four points on the window.

Image '1' :
My finger points to the bottom of the lamp post (quite near to it).

Image '2' :
(Almost similar to the previous image)

Image '3':
Here, my finger points to the top of that lamp post. This spot is quite close to the ones I shown in the previous two images.

Image '4':
Again finger points to the spot nearly close to the ones in images 1 and 2.

Conclusion is all the four points, no matter on which spot on the window I chose them, they all were pointing to the exact one location.

Is this something related to the concept 'line of sight'?

I have already provided the procedure for this experiment for you to test.
Make sure when you are pointing in the perpendicular direction, fix the position of any object you are pointing to or any object which is very very close the spot where your finger is pointing to.

I admit this must be a really different (and sort of weird) topic you all may have never seen on this forum. I wanted some place or someone to tell me answer to my small question (that I have stated above).

I hope I have made myself clear. Please do ask if you want me to show you something more related to this topic.

 

[A.T.]

Conclusion is all the four points, no matter on which spot on the window I chose them, they all were pointing to the exact one location.

The normals to the glass are parallel. They point in the same direction, not to same point. Your methodology is not accurate enough to pick up the difference.