Timeline for Quantum experiments in the pre-industrial era
Current License: CC BY-SA 3.0
9 events
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| Jun 27, 2012 at 3:09 | comment | added | Ron Maimon | Yes, I know orbitals well. You are claiming that it might be possible to infer quantum mechanics_ from the way molecules bind. I think if this was the only way to do it, we would never discover it, because the path is so indirect. Further, we can't even predict the full quantum chemistry knowing quantum mechanics and with supercomputers, so I think it is hopeless to do it this way for a pre-industrial society. But the specific heat anomaly could be noticed with refrigeration (or, in principle, with ovens), but you need thermodynamics to know it's anomalous. | |
| Jun 27, 2012 at 1:34 | comment | added | Steve Byrnes | Do you even know what electron orbitals are? All aspects of chemical bonds and reactivity--not to mention light absorption--is intimately related to detailed properties of the energy, shape, and phase of electron orbitals and their superpositions. Without quantum mechanics you can say "H2O crystals are hexagonal because that's the way H2O is", and likewise with all the millions of other crystals. But an astute person will notice patterns, and investigate, and find that a few rules explain ALL the patterns ... these rules are quantum mechanics! | |
| Jun 26, 2012 at 3:19 | comment | added | Ron Maimon | You can explain this by saying water molecules are little hexagon shaped tinkertoys. This is what pre-quantum atomists supposed. Without a mechanism to peer inside atoms, you don't need quantum mechanics for chemistry at room temperature, but you would for specific heats of cold molecules (the disappearing degrees of freedom) and for thermal blackbody light. | |
| Jun 26, 2012 at 2:53 | comment | added | Steve Byrnes | If you want to correctly explain why ice crystals are hexagonal, you need to invoke the Pauli exclusion principle, quantum superpositions, delocalized electrons, electron spin, etc. etc. Are these not part of quantum mechanics??? The original question asked for "phenomena which require QM to explain them". There is no theory besides quantum mechanics that can correctly and consistently predict the shape of every crystal. | |
| Jun 26, 2012 at 1:41 | comment | added | Ron Maimon | The issue is that the parts of chemistry which demonstrate quantum mechanics require detecting atoms. The blue flash could come from plum-pudding. Without alpha particle scattering from an individual atom, you don't know if it's quantum down there. | |
| Jun 25, 2012 at 22:14 | comment | added | Steve Byrnes | Chemistry requires detecting atoms?? Are you serious?? You don't need to detect atoms to know that ice crystals are hexagonal or that methane flames are blue or that nitrogen gas is less flammable than oxygen. You don't even have to be human to see that grass is a different color than rock! But if you want to explain these facts in a self-consistent and detailed framework, that framework HAS to be based on quantum mechanics. | |
| Jun 25, 2012 at 20:00 | comment | added | Ron Maimon | The problem is that chemistry requires detecting atoms. | |
| Jun 25, 2012 at 18:51 | history | edited | Steve Byrnes | CC BY-SA 3.0 |
added 45 characters in body
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| Jun 25, 2012 at 18:29 | history | answered | Steve Byrnes | CC BY-SA 3.0 |