Fingerprints on Glass: Exploring the Phenomenon

[Numeriprimi]

My thinking today at lunch ...
You fill up the cylindrical glass with water. You take it to hands and you can see fingerprints through the water. The others parts of glass is like mirror. Why you see only fingerprints and nothing else? Can you see similar phenomenon if you use something different on glass? And why is that? What's happens after emptying the glass or fill on with different liquid and why?

Sorry for my bad English and thanks for your answers.

 

[Drakkith]

Frustrated Total Internal Reflection.

http://en.wikipedia.org/wiki/Total_internal_reflection#Frustrated_total_internal_reflection

I'm a bit tired and it's time for bed, otherwise I'd elaborate more. Browse through the links on the article if you find you don't understand something, and feel free to ask more.

 

[Numeriprimi]

Ok, it looks good, I will read it after school.
Is an another example of this phenomenon? (no fingers). What can I put on the glass for this phenomenon?

 

[CWatters]

It says..

Under "ordinary conditions" it is true that the creation of an evanescent wave does not affect the conservation of energy, i.e. the evanescent wave transmits zero net energy. However, if a third medium with a higher refractive index than the low-index second medium is placed within less than several wavelengths distance from the interface between the first medium and the second medium, the evanescent wave will be different from the one under "ordinary conditions" and it will pass energy across the second into the third medium.

The first medium is the glass, the second is air, and the third is finger.

So you should be able to do it with any material that has a higher refractive index than the air.

 

[PJC01]

I find this phenomenon of fingerprints on glass to be quite interesting. The reason why you only see fingerprints and nothing else on the glass is because the oils and sweat from our skin leave a residue on the surface of the glass, creating a unique pattern that we recognize as our fingerprints. This residue is not easily visible on other surfaces, such as a mirror, which is why you only see it on the glass.

It is possible to see a similar phenomenon on other surfaces, such as metal or plastic, but the visibility may vary depending on the material and the amount of residue left behind. For example, fingerprints may be more visible on a metal surface compared to a plastic one.

When you empty the glass or fill it with a different liquid, the residue from your fingerprints is either washed away or mixed with the new liquid, making it less visible. This is because the molecules in the new liquid may not interact with the residue in the same way as water does, causing it to spread out or dissolve.

I hope this answers your questions and thank you for sharing your observation with us. Your English is perfectly fine and I appreciate your curiosity about this phenomenon. Keep exploring and asking questions!