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seen Aug 10 at 3:45

Apr
17
comment Free Energy, Avialable Work in a reversible process
We can introduce any amount of heat into the bath by lowering its temperature by an infinitesimal amount; this is reversible because raising the temperature by an infinitesimal amount will make the heat flow back the other way. The system is also at constant temperature, but may have other internal changes (like a chemical reaction going on), and without taking these into account we can’t calculate $\Delta S$ in the same way, because we can’t guarantee that the equivalent reversible path will end up in the right spot.
Apr
17
answered Free Energy, Avialable Work in a reversible process
May
17
comment Why doesn't light kill me?
@MichaelBrown yep, that KDP. The properties we’re talking about are called “nonlinear optical properties” - see the links in the Wikipedia article.
Feb
4
comment Formation of the overlap in metal electron bands
@Laurent in graphene there are electronic states that are localised between two nuclei, which is what we normally think of as a covalent bond, as well as states that are delocalised across the plane and those that are localised close to atomic nuclei. In sodium and other "typical" metals, ideally there are only delocalised states and states localised close to the nuclei, which is why we wouldn't normally describe this bonding as covalent. But at least in theory you don't have to decide beforehand what sort of bonding you have, just see what electronic states the Schrodinger equation gives you.
Feb
4
awarded  Custodian
Feb
4
reviewed Satisfactory Relation between density and refractive index of medium
Dec
11
answered Force through quantum mechanics
Dec
4
awarded  Caucus
Aug
15
awarded  Yearling
Jul
17
comment What exactly is a kilogram-meter?
@dirtside Well... yes, actually, in the sense that if all you ever wanted to do was move a mass vertically in a uniform gravitational field, then you could indeed measure the work you did in kilogram-metres. Of course you need to include the gravitational acceleration with its proper units to compare to any other form of energy. But my general point is that this is useful wherever something is both proportional to mass and distance(/displacement). In this case it's energy, in in_wolfram_we_trust's excellent example it's emitted CO2. With some imagination it could be almost anything!
Jul
15
answered What exactly is a kilogram-meter?
Jun
18
answered Formation of the overlap in metal electron bands
Jun
18
awarded  Teacher
Jun
17
answered What would make the bottom of my cocktail glass develop a fractured pattern like this?
Oct
30
comment Why does an octave on a piano have the divisions of 8 white keys and 5 black keys?
To be musically pedantic: surely you mean that the E-to-C ratio has an exact counterpart in C-to-A flat!
Aug
15
awarded  Supporter