171–180 of 209 posts
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https://i.kym-cdn.com/photos/images/original/000/992/402/c35... But seriously, it really is time to fix all the chemistry textbooks so that the charge of the electron is +3 instead of −1.
Why, to make all that quark chemistry a bit easier?
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Reading the paper, there is no mention of sizes of molecules. Did Rayleigh actually make the connection between film thickness and molecular size at some point? Or is that just modern retconning?
Replying to myself, I found 1899 paper which is more explicit on the matter, and shows how Rayleigh was not all that certain about the results: The comparison of the present with former results throws an interesting light upon molecular magnitudes. It has been shown (Proc. Roy. Soc. March 1890) that the thickness of the film of olive-oil calculated as if continuous, which corresponds to the camphor-point, is about 2.…
I definitely thought so too, in the first paper the 1.67 isn't even really his primary guess so definitely some presentist bias in the OP
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> if I were to drop you on an alien world with only a telescope and an accurate time keeper, you're not going to be able to recreate it. But you can relatively easily derive the distances too with timekeeper and telescope, by applying Keplers laws?
One can, in principle. Most people lack the talent. (It's a skill that almost anyone could learn, but that doesn't make it a skill everyone has .)
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One can, in principle. Most people lack the talent. (It's a skill that almost anyone could learn, but that doesn't make it a skill everyone has .)
That’s not the definition of talent
I love articles like this. I feel like too often in science education (at least my science education) that laws and theories are presented as just something that you need to memorize, when in my opinion the stories of how things were originally discovered and figured out is eminently more fascinating and inspiring. Like I remember having to learn all of these biochemical pathways, but I left school with nary a clue a…
Pretty sure I remember recreating this experiment in high school chemistry.
Even our math teacher would tell us the stories of how mathematicians "came" to their solutions.
A good teacher makes such a huge difference
> Assuming that the oil formed a single layer of molecules — a monolayer — then the thickness of the oil film is the same thing as the length of one oil molecule. How did he know that the film of oil was one molecule thick? It feels like a huge assumption to me, but maybe this blog post left something out.
Scientists frequently have to make assumptions in order to make progress. Famous example is Darwin figured out that traits are inheritable by natural selection, and this is the driving force of evolution, without having any concept of the physical nature of DNA, or how genes could change (eg. by DNA mutation) to develop adaptations and thus make an organism more fit.
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Except that you could have part of the surface covered in 1 molecule, and another portion covered in 2 molecules. Since you never directly measure the thickness, this would produce the same apparent thickness as a uniform 1.5 molecule thick layer.
That's not how fluids work. The molecules spread out to form an even surface everywhere, so you can't have local high spots. You'd have to put in enough oil to cover the entire surface, and then put in more.
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Why, to make all that quark chemistry a bit easier?
Because electric charge is quantized, so measuring it in thirds is just dumb.
It would have revealed a lower layer of higher understanding.
No one has been able to calculate the mass of a quark:
"Nobody has seriously calculated theoretically a quark mass from first principles. So there is no issue of agreement with experiment. They are parameters in experimental fits, but sometimes remarkably consistent across a broad range of experiments-- and the QCD/EW calculations using them as inputs. If someone pretends to know their origin, he/she is bluffing."
But the exercise is extraordinary!
30 years later, Henry Cavendish measured G and estimated the density of the earth. Using candles, mirrors and telescopes.
In 1676 Roemer estimated the speed of light by timing the orbit of Jupiter’s moon Io, noting that as the Earth approached Jupiter, Io emerged from behind Jupiter a little earlier every day, and as the Earth traveled away from Jupiter it appeared a little later every day, with the time of day varying by 22 minutes over a year. Knowing the difference between the two distances, he reckoned that light travels that distan…
So light travels only 0.3 m / nano second, or 11.802 inches.