Timeline for Why does the laser reflect like a semicircle?
Current License: CC BY-SA 4.0
14 events
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| Oct 13, 2019 at 19:04 | comment | added | Jagerber48 | @JossieCalderon Please include diagrams of what you are describing if you would like any more detailed responses than you've received so far. You are not clearly communicating your setup (and I'm not the first person to tell you this in this question). The diagrams should indicate the orientation of the plaque the direction from which the laser beam approaches and leaves the plaque as well as the declination angle between the laser beam and surface normal and how the beam looks as a function of these things. All of those details are relevant to understand the phenomena you are observing. | |
| Oct 13, 2019 at 14:37 | comment | added | Jossie Calderon | I just told you IT MAKES THE SAME PATTERN AT DIFFERENT ANGLES. | |
| Oct 13, 2019 at 2:01 | comment | added | Jagerber48 | @JossieCalderon The reason the pattern changes when you rotate the plaque 90 degrees is because whatever the small structure surface pattern is on the plaque is not isotropic so when light hits at different angles it makes different patterns. This hypothesis is correct. Maybe you can propose your own hypotheses as you perform more tests. | |
| Oct 12, 2019 at 22:58 | vote | accept | Jossie Calderon | ||
| Oct 12, 2019 at 22:58 | |||||
| Oct 12, 2019 at 17:33 | comment | added | Jossie Calderon | And your hypothesis is incorrect. When I tilt the plaque 90 degrees so the text is sideways, I get a straight line as the second picture - not an arc with left or right curvature... | |
| Oct 12, 2019 at 17:32 | comment | added | Jossie Calderon | Yes. Instead of pointing it directly at the plaque I'll point at it from the right. Same arc. | |
| Oct 12, 2019 at 17:29 | comment | added | Jagerber48 | @JossieCalderon Then perhaps everywhere on the surface the granular structure is horizontal oriented with slight downwards curvature. Does the arc persist even if you illuminate the same plaque at a different angle? | |
| Oct 12, 2019 at 17:28 | comment | added | Jossie Calderon | unfortunately it is inaccurate...the arc persists anywhere you shine the laser. It is the only shape and does not change. | |
| Oct 12, 2019 at 17:21 | comment | added | Jagerber48 | @JossieCalderon A close up image of the plaque material would help make it more clear what you are talking about. In any case, what you say lends more evidence to my idea that small scale granular structure (possibly from the polishing process for the metal) creates a sort of fun house effect on the light which stretches it depending on the granular orientation of the roughness. Is there anything you do not understand about my answer? | |
| Oct 12, 2019 at 16:11 | comment | added | Jossie Calderon | It's not about text orientation. It's about the plaque material orientation. Imagine the text sideways. That's what I mean. | |
| Oct 11, 2019 at 23:26 | comment | added | Jagerber48 | Also the 4th place plaque looks like it is vertical to me. I am basing this on the fact that I assume the plaque is mounted on a wall and then surface above the plaque is the ceiling. Then, given how the text is oriented, it looks to me like that plaque is mounted vertically. I don't know why you're saying it's horizontal. | |
| Oct 11, 2019 at 23:25 | comment | added | Jagerber48 | @JossieCalderon per the hypothesis in my answer I would need information about the granular structure of the plaques at the location where the laser beam is hitting the particular plaque. That is, what matters is the granular structure where the beam hits the plaque. What pattern do you see if you shine the light on a particular location of a particular plaque at many different angles? What if you shine it on many different locations at different angles? What if you repeat the same set of experiments on many other plaques? | |
| Oct 11, 2019 at 22:53 | comment | added | Jossie Calderon | what more information do you need? They're the same plaque material despite different names. But the 5th place one is a vertical version of the plaque; the 4th place is horizontal. | |
| Oct 11, 2019 at 17:00 | history | answered | Jagerber48 | CC BY-SA 4.0 |