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Messages - Bored chemist
« on: 05/09/2023 23:04:38 »
length of the air column and the timbre of the harmonics are determined by the wood (or metal in most cases nowadays) .So, a brass flute would sound more like a tin whistle than like a wooden flute.
And a wooden flute would, I guess, sound like a recorder, rather a metal flute.
I suspect that the reason why plastic musical instruments exist is that, to a first approximation, the timbre depends on the shape of the instrument.
It would certainly be interesting to fill a flute with helium (or hydrogen, if you are concerned that He isn't a renewable resource) and close it with cling-film so you don't blow any air through it.
I suspect the tone would not be improved by a bit of thin plastic, but it would illustrate a point.
: if you filled your trombone or bagpipe with helium, would that alter its pitch?One way to find out; check on YT and see if it's been done.
Apparently, if you put helium into a bagpipe it turns into laughing gas.
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« on: 30/08/2023 09:08:57 »
« on: 28/08/2023 11:13:59 »
Pesticides?That's probably the only thing we can rule out.
The problem is that "broad beans" covers a large range of slightly different plants.
So the differences might not arise from how they were treated but simply be because they are different strains.
The following users thanked this post: vhfpmr
« on: 28/08/2023 10:38:42 »
« on: 25/08/2023 14:23:00 »
OKHow big is your apparatus?Let's pretend that the apparatus is similar to what's shown here. Just replace the salt bridge with a tube, filled with a mixture of solutions from both containers.
And how far do you think the electrostatic effect of an ion's charge reaches before it is too small to influence things?
It's related to this
in water the species will be H3O+, H5O2+ and possibly some others( can't remember offhand).A fairly common model assumes that the species (in dilute solutions ) is H9O4 +
It's about a nanometre across.
It's obviously got a positive charge on it and it will attract the water molecules around it.
But that attraction isn't strong enough to overcome the forces arising from the random molecules in the liquid.
If it was then there would be more water molecules "stuck on" and you would have H11O5+ or H13O6+
So we know that the effective range of teh electrostatic forces on a H+ ion in solution in water is only about a nanometre.
So, once again; how big is your apparatus?
If it's more than a few nm you can pretty much ignore the direct electrostatic effects.
« on: 22/08/2023 19:02:51 »
Thanks for clarifying that pi means the osmotic pressure rather than pi.pi = iMRTIMO, it's hidden in the dimension of osmotic pressure pi, which is ML(-1)T(-2).
The higher the value of pi, the lower the equilibrium time will be. It can be done by increasing temperature.
As you said, diameter and length of the connecting tube will also be influential.
That makes more sense now.
But rates of reaction are not strongly related to osmotic pressure.
Osmotic pressure is, itself, an equilibrium process and "getting to equilibrium" has kinetics of its own and an associated timescale.
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« on: 15/08/2023 08:33:12 »
That CAN'T be true! / Re: Why has the 97% trope of scientists about global warming not been challenged?« on: 12/08/2023 11:18:41 »
I think I have a clear understanding of the points made by Alancalverd and BC. Alan says the absorption band is already saturated. BC agrees with this analysis but points out that the absorption will occur at lower atmospheric levels as the co2 concentration rises and this makes perfect sense if we had a static atmosphere but we know the atmosphere is highly turbulent. It would be a hell of a problem to analyse rigorously. Me, I am still sitting on the fence( hoping to not get splinters in my butt ) in a state of confusion.It's not a trivial problem, but here's a useful simplification.
Compared to radiative heat transfer (at the speed of light) the atmospheric mixing which is over a millionfold slower, is too slow to make a difference (on average).
So we can treat the air as a set of layers- each of them is "one average photon path length" thick.
To get out the heat has to make it through each layer in turn (and at each layer there's a near 50: 50 chance that it heads down rather than up).
Adding more CO2 decreases the path length and thus makes each "layer" thinner.
But the depth of the atmosphere is substantially constant.
So we get more layers.
So it's harder for the heat to escape.
Incidentally, no transition is ever strictly saturated, the layers could be arbitrarily defined as say a 99% absorption of the IR in a particular wavelength band.
"Travelling by train produces up to 513% less carbon emissions than flying".So, your argument is something like "Because someone wrote bad advertising copy, physics is wrong".
but the key processes of photosynthesis incorporate it into the -CH2- skeleton of carbohydrates and other complex molecules.We know.
And the reaction is (roughly- assuming it makes glucose)
6 CO2 + 6 H2O -- > C6H12O6 + 6 O2
And if that cellulose burns or metabolised for energy, you get back to where you started. So we can ignore that.
But one potential fate of the glucose it to become coal.
C6H12O6 --> 6C + 6 H2O
So, for every C atom in coal there should be exactly 1 O2 molecule produced.
It's slightly more complex when you consider the hydrogens, but it's not an "order of magnitude" thing.*
Every atom of carbon reduced from CO2 generates a molecule of O2.
There should be an almost exactly 1 to 1 correspondence between reduced carbon atoms and oxygen molecules.
So you should be able to write that the other way round.
There should be exactly 1 carbon atom in "fuel" for every O2 molecule in the atmosphere.
But, in fact, there seem to be a lot more.
Where did they come from?
Or, equivalently, where did the carbon go?
Where do you think the carbon went?
It's not been made into coal or oil.
It's not been made into imaginary elephants either.
So where is it?
* Conceptually, I can ferment the glucose to alcohol, dehydrate it to ethylene and oligomerise / crack the ethylene to any length carbon chain I like (with either a double bond or a ring).
None of those reactions involve O2 so making "oil" does not change the fundamental 1 carbon atom per oxygen molecule ratio.
Faffing about with amines and thiols etc slightly complicates things.
« on: 01/08/2023 18:02:03 »
Physics, Astronomy & Cosmology / Re: Will there be an e field outside two concentric spheres differentially driven?« on: 26/07/2023 17:42:53 »
My maths is bad but this looks like a start.
Physics, Astronomy & Cosmology / Re: Will there be an e field outside two concentric spheres differentially driven?« on: 26/07/2023 15:45:11 »
Without doing the maths, I think any field would be contained within the faraday cage consisting of the outer sphere.
That CAN'T be true! / Re: Why has the 97% trope of scientists about global warming not been challenged?« on: 24/07/2023 18:45:40 »
For the record, it was Alan's point about the absorption being saturated that got my attention and not the historical record. I do accept that there has been an unprecedented rise in co2 due to use of fossil fuels.Hi Paul.
I think it might have been before you joined the forum that I explained why "saturation" isn't the killer that Alan thinks it is.
I have had to explain this to him more than twice...
sorry not buying itThere are three reasons for not "buying" reality.
Stupidity, insanity or dishonesty; and they are not mutually exclusive.
Calling you a troll is the least impolite.
« on: 22/07/2023 22:03:13 »
BC, we are all a bit odd, so are we all neurodiverse? In that case the term loses it's meaningNo
The difference is between "some people are 'different' " and "some people are 'wrong' ".
There are spectra of intelligence and height; everyone is on them somewhere.
Does that mean that height and intelligence are meaningless?
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« on: 22/07/2023 18:52:20 »
The problem with newspeak is that it takes as axiomatic that any adjective describing a deviation from the norm is in some way unacceptable and discriminatory,That's the exact opposite of what recognising neurodiversity is about.
"Neurodiversity is a proposed framework that argues there is intrinsic diversity in human brain function and cognition, and that certain things currently classified as neurodevelopmental disorders are differences and disabilities but are not necessarily pathological."
« on: 21/07/2023 17:23:33 »
Forgery is forgery, and we've had to live with it for as long as anyone has valued authenticity.Yes.
But my chequebook was only at risk from a skilled forger.
That wasn't a big threat to me.
But now any Tom Dick or Harry can make a practically perfect facsimile of my signature/ face/ social media account/ whatever.
So, yes, forgery was always a problem.
But it suddenly got much worse.
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« on: 21/07/2023 08:37:22 »
It's interesting. I'm sure the phrase "kicked the bucket" is more common, but- at least to me- it's more difficult to work out the connection between what it says and what it means.