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 Apr 25 comment Do all equations have identical units on the left- and right-hand sides? It makes a lot of sense what you're saying. In fact, IMO, it's wrong to even say an equation “is written in unit system $X$” at all. A physics equation is written without reference to any unit system (although, for a fact, in some equations certain constants just collapse to 1 if you use a particular system). The objects on both sides of such an equation are not numbers at all, but, well, physical quantities. You can evaluate e.g. a length in a particular unit, but the quantity as such doesn't have a unit. Apr 25 revised Do all equations have identical units on the left- and right-hand sides? added 31 characters in body Apr 24 comment Do all equations have identical units on the left- and right-hand sides? There's nothing wrong with adding $1\:\mathrm{m}$ to $3''$ (apart from general reservations one might have about using non-SI units). The result is $1.0762\:\mathrm{m}$. Or – this is a correct approximate equation! – $1.08\:\mathrm{m} \approx 42.4''$. Mar 28 revised Is it possible for a harmonic to be louder than the fundamental frequency? added 307 characters in body Mar 28 answered Is it possible for a harmonic to be louder than the fundamental frequency? Mar 28 comment Is it possible for a harmonic to be louder than the fundamental frequency? Nice, though one needs to be careful: the spectra displayed in audio software generally don't properly represent amplitude uniformly for all frequencies, but are in some way graded frequency-dependently. But I think trumpet is indeed an instrument where the fundamental does not have the highest amplitude. Mar 27 comment How to interpret the units of the dot or cross product of two vectors? Good answer, though IMO it's a bit strong to say the dot product of two lengths “will nowhere occur in physics”. For instance, it can certainly make sense to consider such a product if you simply want to assert that two things are orthogonal, by setting $\vec{a}\cdot \vec{b} = 0$ (which of course means you can just cancel the units). Of course, it might be objected that you're really invoking the Hodge star operator in this case, but that would arguably overcomplicate matters. Mar 25 revised Why does moonlight have a lower color temperature? added 645 characters in body Mar 24 comment Why does moonlight have a lower color temperature? So, to get this clear... the third photo was taken with the same settings as the first, except longer exposure and different time of day? Mar 24 awarded Nice Answer Mar 23 comment Why does moonlight have a lower color temperature? Yeah, I suppose so. Rayleigh scattered moonlight is mostly notable at full moon, midnight, and then it is, in fact, blue – obviously. But that light doesn't dominate the night sky, you still see stars and often also skyglow. Mar 23 comment Why does moonlight have a lower color temperature? @KartickVaddadi An interesting proposal! I'd conjecture that, if you leave white balance the same and only change exposure time, then the night-time photo would look overall pretty reddish, or the daylight scene blueish. Taken on their own, sun and moon would have almost the same colour in their respective picture, but in context the sun might be perceived yellower, due to the effect I discussed in my answer. Mar 22 revised Why does moonlight have a lower color temperature? Add optical-illusion picture Mar 22 revised Why does moonlight have a lower color temperature? Add optical-illusion picture Mar 22 answered Why does moonlight have a lower color temperature? Mar 16 comment Is the velocity with which molecules of the medium oscillate same as velocity of the sound in that medium? Remarkably enough though, sound speed in a gas is about the same as the mean speed of thermal motion of the particles! This follows from the equipartition theorem. (It's not in fact the same speed; for a monoatomic gas it's about 75%.) Mar 11 awarded Great Answer Mar 11 revised Why does matter exist in 3 states (liquids, solid, gas)? Two small typos Mar 9 revised Why does matter exist in 3 states (liquids, solid, gas)? “it is seems evident”... one verb too many. Mar 9 revised Why does matter exist in 3 states (liquids, solid, gas)? Sublimation not at all pressures