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I remember as a child being extremely puzzled as to how glass worked. I could not understand how something solid could be transparent. I had seen that when thin
by iamflimflam1 5y ago
I remember as a child being extremely puzzled as to how glass worked. I could not understand how something solid could be transparent. I had seen that when things moved quickly they seemed to become translucent so I came to the conclusion that glass was made up of tiny cogs, all moving extremely quickly. It never made complete sense though. I must have driven my parents insane with my constant questions of how glass really works. Frustratingly I don’t think they really understood why I was so fascinated by it.
- andi999 5y agoSounds not less intuitive than the band gap explanation. How did you explain color tinted windows?
- barrkel 5y agoEven weirder is how glass is partially reflective. What mechanism lets some light through but sends other light off in such a regular ordered way?
- darkerside 5y agoCrystals are by definition ordered by a very regular pattern. I don't fully understand the mechanism, but I'm not surprised that it exists.
- agumonkey 5y agonot long ago I learned about metallic glass
- kmm 5y agoBut glass isn't crystalline, it's amorphous, there's not really any order there on the atomic level.
- darkerside 5y agoGlass is not a crystal. Not sure what I was thinking. No idea why its surface is reflective.
- nate_meurer 5y agoAny abrupt change in refractive index, either higher or lower, will result in reflections. This can be somewhat intuited by analogy to sound waves, which reflect off of abrupt material density transitions. This is how anti-reflective coatings work-- by "smoothing" the transition using materials that have intermediate refractive indices. E.g., flourite coatings on glass lenses.
- barrkel 5y agoI don't think people necessarily have an intuition about sound waves reflecting on material density transitions (the obvious one is air vs water but I guess unless you grew up near a lake or slow river you wouldn't know much about it), and I don't think it's clear how such an intuition - if present - would transfer from sound, which has a transmission medium, to light, which doesn't. Sound is transmitted by waves of compression and decompression in the medium. In the reflection scenario that's is ultimately molecules of air and water hitting the boundary and transmitting some kinetic energy into the other medium and bouncing back, to some degree. You can visualize it as marbles hitting each other. It's much harder to do the same for light.
- darkerside 5y agoI think that does make sense. A more extreme example is echos caused by sound bouncing off of solid materials. Definitely intuitive to me, unless someone can again explain why I am wrong. :) That said, it explains why glass is shiny, but not necessarily why it is reflective. At least to my understanding.
- agumonkey 5y agoisn't empty space made up of virtual particles aka particles with a life time so minute it's basically not there ? :)
- wyldfire 5y agoThe atmosphere on Earth has stable particles -- they have a lifetime similar to other matter on Earth. But their density is so low that light passes through them mostly undisturbed. Empty space outside of planetary atmosphere is a void, there's "no" particles there (some Hydrogen and Helium and radiation).