We know that a window can actually reflect light. But if the window has some dirt sticking to it, the image we see sometimes get magnified. Why?

Question

Well, I was traveling in a bus yesterday and saw this occur. The board that separates the passengers from the driver's had something written on it and I saw that the window that was a few meters away from the board reflected all of the things written.. But the window had some dirt on the part where I saw the image of the writings... And, they appeared to be enlarged just at the point where dirt was present.

Answer 1

The open spaces between dirt particles each acts like a "pinhole camera" to magnify the image behind the dirty glass pane. The magnification is slight but noticeable. Try this experiment: make a small triangular hole shape by putting three fingertips together so as to leave a gap at their intersection. by pressing your fingertips together, you can make the size of the hole shrink; by relaxing them, you can make the hole larger.

That hole will act as a pinhole camera. now look through the hole at your computer screen from about 24 inches away and vary the hole size. you will find a certain diameter at which the image you see through the hole will get sharper and the text on the screen will become easier to read.