41

Physics, Astronomy & Cosmology / Re: Why is air a thermal insulator?

« on: 02/02/2024 11:08:54 »

This sort of thing

Sorry i cannot believe convection

Is the reason why I posted stuff that led to this
"For reasons of repetitive antagonism, this user is currently not responding to messages from;
BoredChemist"

It's not just that he can't science, it's that he refuses to science.

42

Physics, Astronomy & Cosmology / Re: Can Planck's law curve be matched to Rayleigh-Jean's law curve like this?

« on: 27/01/2024 15:04:59 »

  1 rpm or 1 rad/second is not a frequency, but a speed of rotation.

Or it's a rate of change of phase angle.
In which case  hamdani yusuf's statement makes sense.

43

The Environment / Re: How are global warming and world population expansion linked?

« on: 25/01/2024 00:06:50 »

The problem is the refugee camps give free food and medical aid

The problem is typically war or something from which people, understandably, seek refuge.

What happens after they leave their homes is a bit beside the point.

We must find a way of controlling population expansion in refugee camps everywhere!

We could stop selling weapons...

44

Physics, Astronomy & Cosmology / Re: Can Planck's law curve be matched to Rayleigh-Jean's law curve like this?

« on: 24/01/2024 12:50:02 »

Does the unit of the radiation frequency have no effect on the numeric value of their quantum of energy?

The number of joules of energy which a photon carries  doesn't know or care if you measure frequency  in 1/seconds or 1/weeks
The value of Planck's constant (h) would change.

45

Physics, Astronomy & Cosmology / Re: Can Planck's law curve be matched to Rayleigh-Jean's law curve like this?

« on: 22/01/2024 14:18:08 »

I also am fairly sure a rotating magnet would radiate em. It would have to rotate at quite a high speed to generate easily detectable radiation. I have been trying for several hours to mentally model the maths involved but I have failed so far. We normally look at charge acceleration to produce em as it is the most convenient method but one has to remember that the magnetic field is simply the electric field as seen from a different frame of reference.

I never could do the maths, but I don't care.

I can get a toy magnet and put it on the turntable of a record player.

I can put a compass near it.
And I can watch the compass needle move.
If I'm lucky it will even rotate in synchrony with the turntable.

The force acting on the needle is electromagnetic.

The carrier of the EM force is the photon.
So, in this case, I know that a rotating magnet emits EM radiation. That force is periodic and thus there must be a component of the EM radiation with the same period.So it must have photons with energies corresponding to the frequency of rotation of the record player.


Re. "but a magnet in an infinite vacuum won't. "
If the magnet falls over in a non-existent forest with no observers, does it matter?

I contend that it will still emit EM radiation.
Imagine that we somehow have a magnet in an infinite empty universe.
We set it spinning (We know it is spinning, because an ant who happens to be standing on it notices the centrifugal effect).

After a while, and at some distance from the magnet, we magically call a compass needle into being.

Does the needle have to "wait" for EM radiation from the magnet to reach it, or is that changing field already there?

I can't see how it would so I think the magnet must have been emitting EM radiation all along.

But... if there's EM radiation, then there are photons.
And, if there are photons, the universe isn't empty.
So the solution may be that you can't have a rotating magnet in an empty universe.

All seems a bit esoteric..
But let's ignore nearly the whole of the universe and consider some hydrogen atoms.
Some of them have the magnetic dipoles of the electron and the proton aligned parallel, and in others it's antiparallel.
And if one happens to flip from the first state to the second, it emits a photon of about 21 cm wavelength.

That photon crosses space and is picked up many years later by a detector here on earth.

But we have only been constructing such detectors for about 100 years.
So, for a source more than 100 light years away, the detector had not been built when the photon was emitted.

I think that's close enough to " we magically call a compass needle into being." for the analogy to work.

An electron- with a magnetic diploe moment- was flipped and sent out EM radiation. It did so in a universe in which the detector did not exist.
You may say that, without the proton of the hydrogen atom, the energy of the photon would be undefined. Which is a fair point
But, at that point, I think you need to be able to do Laplace transforms and, as I said, I can't do the maths.

46

General Science / Re: What Is Gray?

« on: 20/01/2024 00:19:08 »

Nonsense, most people drive in a way to prevent damage to their car, seat belt or no, the idea of imminent demise is not really a thought.  Seatbelts save lives.

OK imagine that one day you are asked to drive to a meeting across town. They give you  an armoured truck to make the trip.
Then, the next day, for the  same trip, they give you a rickety old schoolbus  which has a bottle of nitro-glycerine on the  next seat and dodgy suspension.

Do you drive the same way in both cases, or do you adjust your driving according to the apparent risk?

Anyway, here's some data. from
https://en.wikipedia.org/wiki/Reported_Road_Casualties_Great_Britain


Seat belt death.png (118.79 kB . 1024x650 - viewed 1064 times)

47

New Theories / Re: New theories

« on: 19/01/2024 13:09:35 »

spray with unsaturated Olea europea lipids

How do you remove the saturated ones?

48

Physics, Astronomy & Cosmology / Re: How do astrochemists and astrophysicists know what exoplanets are made of?

« on: 12/01/2024 14:19:14 »

https://en.wikipedia.org/wiki/Spectroscopy

49

The Environment / Re: Is it possible for hydrogen sulfide clouds to form on Earth?

« on: 11/01/2024 12:49:00 »

How common is it for people to be overcome by gas emissions from swamps?

I know it happens with this sort of thing
https://en.wikipedia.org/wiki/Lake_Nyos_disaster
and even this
https://en.wikipedia.org/wiki/Cave_of_Dogs

I know people get stuck in swamps and die of exposure or drowning.
But I never heard of anyone being gassed.

50

That CAN'T be true! / Re: Is HCQ the antidote to Trump?

« on: 09/01/2024 12:59:31 »

OK, now the dust has settled, someone did the analysis.
https://www.sciencedirect.com/science/article/pii/S075333222301853X

17000 dead as a result of HCQ.

Can one of the mods correct the thread title please?

51

Chemistry / Re: Ammonium perchlorate

« on: 09/01/2024 10:10:13 »

Is it Toxic &/Or Explosive?

https://en.wikipedia.org/wiki/PEPCON_disaster

52

Just Chat! / Re: Why Is English So Simple?

« on: 29/12/2023 18:08:54 »

Before you ask "Why Is English So Simple?"
you should ask
"Is English So Simple?".
And the answer to that is
"can you read this out loud?"

I take it you already know
Of tough and bough and cough and dough
 Others may stumble, but not you
On hiccough, thorough, laugh, and through. 
And cork and work and card and ward
And font and front and word and sword
Well done! And now if you wish, perhaps
To learn of less familiar traps,
 Beware of heard, a dreadful word
That looks like beard and sounds like bird.
 And dead: it?s said like bed, not bead?
For goodness sakes don?t call it deed. 
Watch out for meat and great and threat,
They rhyme with suite and straight and debt.
 A moth is not a moth in mother,
Nor both in bother, broth in brother. 
And here is not a match for there,
And dear and fear for bear and pear.
And then there?s dose and rose and lose?
Just look them up?and goose and choose, 
And do and go, then thwart and cart.
Come, come, I?ve hardly made a start!
 A dreadful language?
 Man alive!
I?d mastered it when I was five.

53

General Science / Re: Is desalinated ocean water just as healthy as any other purified water?

« on: 23/12/2023 16:19:29 »

Essentially all fresh water is desalinated ocean water.
Sometimes the desalination process involves the sun + clouds etc.

54

Science Experiments / Re: How does microwave superheat water?

« on: 18/12/2023 16:10:52 »

On the other hand, in microwave superheating, the boiling can occur long after the heater is turned off, and the water is moved away from the microwave.

I assure you that this happens with conventional heating too.

That's the reason for instructions like this
"The avoidance of ?bumping? can be achieved by the addition of pieces of broken pot or special anti-bumping
granules, which promote smooth boiling. Anti-bumping material should only be added to a cold liquid. If there is a
need to add it to a liquid that has already been heated, the liquid should be removed from the heat and allowed to
cool for several minutes, otherwise it may boil over.''
here
https://www.ase.org.uk/sites/default/files/chemistry%20PDFs/PDFs/Anti%20bumping%20granules.pdf

55

New Theories / Re: Solving the puzzle of wave-particle duality, solution of this problem

« on: 13/12/2023 22:40:08 »

Can Light be thought of as Water?

A Single Photon as a Droplet.
& a whole bunch of em as an Ocean.

No
Because wavelengths don't "mix" when photons collide.

56

Chemistry / Re: Will melting Plastic in a tight container exPlode?

« on: 10/12/2023 12:32:34 »

Heating anything in a completely sealed container is a bad idea  unless you take suitable precautions.

Why do you want to heat  plastic?
Many plastics can be melted in an open container.

57

New Theories / Re: Solving the puzzle of wave-particle duality, solution of this problem

« on: 10/12/2023 09:54:04 »

So why, in the double-slit experiment mentioned by Zer0, light manifests itself as a wave phenomenon.

Because that's what quantum objects do.

This is a picture of a quagga.

Quagga.png (301.91 kB . 569x399 - viewed 430 times)
From the front it looks like a zebra and from the back it looks like a horse.

Because it sometimes looks like a zebra, we know it is not a horse.
Because it sometimes looks like a horse we know it is not a zebra.

So we know it is "something else". We call that thing a quagga to distinguish it from zebras and horses.

From some viewpoints, light looks like a wave.
From some viewpoints light looks like a particle.

Because it sometimes looks like a wave, we know it is not a particle.
Because it sometimes looks like a particle we know it is not a wave.

So we know it is "something else". We call that thing a quantum object to distinguish it from waves and particles.

There is only a "problem" if you try to pretend that light is a wave or a particle.
To be fair, you can often model it as if it is one or the other.

58

Physiology & Medicine / Re: Wintertime and Hand Washing. Whose Directions Do You Follow?

« on: 09/12/2023 00:37:33 »

The Swarfega just removes the barrier cream

And then stops... by magic.
Because it knows that the greasy stuff that you put on your skin is different from the greasy stuff that's part of your skin.

59

Physiology & Medicine / Re: Does Your Brain Remember Everything?

« on: 06/12/2023 22:55:41 »

I thought I already replied to this...

60

Physics, Astronomy & Cosmology / Re: Has E=mc2 been proved practically?

« on: 06/12/2023 13:10:51 »

electromagnetic energy is massless

That's a matter of perspective. Light has no rest mass, but it has relativistic mass.