Timeline for Are water molecules at the surface closer or farther apart than the molecules inside?
Current License: CC BY-SA 4.0
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| Mar 18, 2022 at 17:31 | comment | added | user21820 | I think both oliver and Jeffrey are wrong. The distribution of water molecules at the air-water interface will show a smooth increase, but that tells you nothing about the orientations of the molecules or what is actually happening at the interface. For example, you can get the same distribution even if you have a greatly denser surface 'skin' as long as that layer is not completely flat! For the same reason, Chemomechanics' comment fails to provide enough evidence. | |
| Mar 18, 2022 at 3:53 | answer | added | Jeffrey J Weimer | timeline score: 2 | |
| Mar 17, 2022 at 23:56 | answer | added | benrg | timeline score: 2 | |
| Mar 17, 2022 at 14:06 | comment | added | Jeffrey J Weimer | We should not have to invoke hydrogen bonding to explain the answer. Otherwise, how would we answer the same question for liquid methane? Or even liquid argon? Also, the answer should resolve whether and why we should expect variations in density as we travel from the bulk liquid through the surface to the gas (normal to the surface) versus as we travel laterally in the surface plane. | |
| Mar 17, 2022 at 9:05 | answer | added | MatterGauge | timeline score: 0 | |
| Mar 17, 2022 at 8:29 | answer | added | oliver | timeline score: 14 | |
| Mar 17, 2022 at 6:51 | history | edited | Qmechanic♦ |
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| Mar 17, 2022 at 3:44 | history | became hot network question | |||
| Mar 17, 2022 at 3:00 | history | tweeted | twitter.com/StackPhysics/status/1504291500011757569 | ||
| Mar 17, 2022 at 0:18 | comment | added | EB97 | @user400188 You probably right but I don't want to be annoying and bother him much, that's also why I ask questions here | |
| Mar 17, 2022 at 0:11 | comment | added | user400188 | I would word it different to @Chemomechanics, but there should be nothing wrong with asking your professor for peer reviewed sources. They will probably just take it as a good sign that you are progressing as a student. | |
| Mar 16, 2022 at 23:47 | answer | added | Philip Wood | timeline score: 6 | |
| Mar 16, 2022 at 23:32 | comment | added | Chemomechanics | If you’re not allowed to ask for evidence, you’re studying dogma, not physics. | |
| Mar 16, 2022 at 23:31 | history | edited | EB97 | CC BY-SA 4.0 |
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| Mar 16, 2022 at 23:06 | comment | added | EB97 | @Chemomechanics I think it will come out a bit rude to ask him for that... but can you please explain to me what is wrong in the explanation I cited above? | |
| Mar 16, 2022 at 22:58 | comment | added | Chemomechanics | I'd like to see peer-reviewed evidence for your lecturer's comments as well. | |
| Mar 16, 2022 at 22:50 | comment | added | EB97 | @Chemomechanics If I understand correctly, that means the three videos are wrong and my lecturer is right? If so, what is wrong in the explanation I cited in the comments? | |
| Mar 16, 2022 at 21:10 | comment | added | Chemomechanics | Citation needed for the video's "Surface molecules are compressed more tightly together, forming a sort of skin on the surface". Most water–air interface models look like Fig. 2 here or Fig. 2 here, showing a smooth but sharp increase up to the bulk density. Water is of course compressible (bulk modulus 2 GPa). | |
| Mar 16, 2022 at 20:48 | comment | added | EB97 | Can someone approve that answer? It is hard for me to believe that a physics proferssor is wrong about a thing like this. | |
| Mar 16, 2022 at 20:46 | comment | added | EB97 | On the third video I linked, someone asked this question and the answers is: "Good question! It is not the amount of H-bonds occurring, but the net direction. The net direction of the force of H-bonds below the surface is zero, since the H-bonds are occurring in all directions. However the H-bonds occurring with surface molecules are not occurring in all directions, and so there is a net direction toward where the H-bonds are occurring, which is downward, meaning the surface molecules have a net downward force, pulling them toward a smoother surface, meaning they are coming closer together. | |
| Mar 16, 2022 at 20:36 | comment | added | Marc Barceló | I think that the energy of the molecules at the surface is higher because every molecule is contiguous to less molecules. Indeed I think that the khan acamedy first video is right. | |
| Mar 16, 2022 at 20:35 | history | edited | EB97 | CC BY-SA 4.0 |
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| Mar 16, 2022 at 20:18 | history | edited | EB97 | CC BY-SA 4.0 |
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| Mar 16, 2022 at 20:08 | history | edited | EB97 | CC BY-SA 4.0 |
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| Mar 16, 2022 at 20:01 | comment | added | Marc Barceló | Water is compressible, but much less than other fluids. | |
| Mar 16, 2022 at 19:56 | history | edited | EB97 | CC BY-SA 4.0 |
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| Mar 16, 2022 at 19:49 | history | edited | EB97 | CC BY-SA 4.0 |
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| Mar 16, 2022 at 19:39 | history | asked | EB97 | CC BY-SA 4.0 |