Stamp Experiment #1: Snell's Law (FAILED)
This was probably a half baked idea from inception...
Snell's Law
Snell's Law observes that there is a relationship between the angle of incidence and the angle of refraction when light passes from one medium to another. With a known refractive index of one of the mediums (like air), and the known angle of incidence, and the angle of refraction after hitting medium 2, we can use these values to determine the refractive index of the second medium.
Why would we want this? With the refractive index of the 2nd medium, we can determine the Brewster's angle, the angle of polarization. I would like to consider this angle for taking different sensor measurements from the reflection surface off of a stamp.
Why do I want to do this? My end goal is to measure several properties before and after using various chemicals to remove modern self-adhesive stamps from envelopes. Am I damaging the stamps? Am I altering them? And to what degree? This leads down a thousand questions and measurements to consider, but this is the first of many steps: is there key angles I should take measurements/pictures from? A quick search leads to talk on the angle of refraction.
The Angle of Refraction
My hope is that stamp paper is thin enough that we can measure the angle of refraction after a laser beam passes through. I expect it to be diffused, but still usable. I may have to use shallow angles of incidence where light gets transmitted into the 2nd medium at greater levels.
Questions I have is how much the angle of refraction is different between different stamps, and also how different it is between stamps that have had the adhesive removed.
The Experiment
The first stage will be to see if the stamp will allow a laser to pass through.
The Result - FAILED
Paper is so opaque it seems to just completely diffuse the laser light and "glow". If any point of light is visible, that point itself is seen as a source of light and how that light is propagated does not seem dependent at all on the angle of entry from the laser.
This was probably a half baked idea from inception and further reading and talks with Chat GPT/google seem to indicate that Snell's law doesn't work so well with opaque materials.
Take-aways. Ask more questions. I also have a cool new green laser now. Not really knowing an angle of refraction has little impact on the rest of my planned observations as I doubt polarized/non-polarized light off of something like paper photographs that differently for my purposes (yes, i could have just gotten a polarizing filter if I'd like - but where's your sense of adventure man?).
AI Disclaimer - AI was used heavily in researching topics around Brewster's angle, Snell's law, and angles of refraction. AI also generated the broken test tube image.