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A "challenge" for you, IB and Into



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15-10-2016 23:45
jwoodward48
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(1537)
Into the Night wrote:
jwoodward48 wrote:
Into the Night wrote:
jwoodward48 wrote:
Into the Night wrote:
Into the Night wrote:
jwoodward48 wrote:
Into the Night wrote:
jwoodward48 wrote:
But the amount of energy that is leaving is decreased!


No.

You have built an energy trap. This violates both the 1st and 2nd laws of thermodynamics.

Not decreased to 0. Decreased.

Any amount of decrease is the trap, even if you don't decrease it to zero.

No, it won't. Remember Stefan-Boltzmann? It still holds somewhat - increasing temperature increases emissions. This means that eventually, the emissions will increase to the intake again.

The amount of energy leaving CANNOT decrease to anything less than the energy arriving.

Waiting for the Magick Blanket argument again in 5...4...3...2...


Yes, it can. Emissivity at one wavelength can differ from absorbance at another.


Whatever is absorbed is emitted at the same frequency, if it emitted at all.


Not so. Remember, there are many collisions per second, even in a gas - an oxygen molecule at STP will have 5.8 x10^9 collisions with other molecules per second! That's over 5 billion! The energy from an absorbed photon will quite possibly be absorbed by other molecules, or turned into simple vibrational energy - or the energy of heat.


In that case, the photon is never emitted. The molecule lost the energy before it could do so.
I have already described this.


And what does that energy go toward? Heating up the gas, right? And that means it can sustain the emitted radiation. Radiation not necessarily at the wavelength of the absorbed radiation.

But even without this, the way that some energy returns to the surface if GHG exist, whereas without them it would not, suggests that the temperature would increase.


An absorbed photon may not heat up a substance at all. It may alter the substance.


Huh? Ah, you mean "it doesn't necessarily heat," not "it cannot heat." Okay.

But the alteration of the atoms frequently results in re-emission, right?


"Heads on a science
Apart" - Coldplay, The Scientist

IBdaMann wrote:
No, science doesn't insist that, ergo I don't insist that.

I am the Ninja Scientist! Beware!
15-10-2016 23:54
jwoodward48
★★★★☆
(1537)
Into the Night wrote:
jwoodward48 wrote:
IBdaMann wrote:
Surface Detail wrote:
Into the Night wrote:
Whatever is absorbed is emitted at the same frequency, if it emitted at all.

If that were so, the Earth would be visibly glowing like a faint sun as it emitted all the solar radiation that it had absorbed. So it obviously isn't so.

You mean like Venus, clearly visible from earth? You mean like that?

It's like that.


.


Why isn't Earth like that, then? Why is Earth radiating pretty much only long-wave radiation, when it (obviously) receives more than long-wave radiation?


I assume you mean infrared again. Please use correct terminology. Longwave is from 30kHz to 300kHz.

No, I'm already using correct terminology. The Earth doesn't significantly radiate anything other than longwave radiation. The Earth receives significantly more than longwave radiation.

Longwave is quite different from infrared. It's infrared in the sense of "longer wavelength than visible," but not in the sense of "between microwave and visible".
Not everything the Earth receives is absorbed. MOST of it is reflected. Seen from space, Earth is quite bright and shiny. On a particularly cold clear night with a new crescent moon in the winter, you can see Earthshine on the dark portion of the moon. That is the glow of the Earth that is so bright the Moon is reflecting some of that shine back at us.

This is best seen in winter, since in summer the sun is up and usually in the way. You will see it off to the west shortly after sunset, just when it gets nice and dark. Usually just before the Moon itself sets.


Agreed, only about half of the sunlight that reaches Earth is absorbed by the surface. Of the remainder, about half is reflected (by the atmosphere or surface) and about half is absorbed by the atmosphere.

The Earth's surface is roughly a gray body, right? This means that it can absorb most of the light that hits it. Only 10% or so of the light that hits the surface is reflected; the rest is absorbed. But we see a very different emission spectrum than what is absorbed, don't we?


"Heads on a science
Apart" - Coldplay, The Scientist

IBdaMann wrote:
No, science doesn't insist that, ergo I don't insist that.

I am the Ninja Scientist! Beware!
15-10-2016 23:55
jwoodward48
★★★★☆
(1537)
Into the Night wrote:
jwoodward48 wrote:
Yes, I was referring to the visible glow. All gases radiate, even if no light is hitting them. Absorbed radiation can go toward heating the object, right?


IF the photon absorbed happens to be in the infrared band, yes.

More energetic colors tend to do things like break or make chemical bonds, or even modify the atom itself, by kicking an electron so hard the atom becomes an ion.


Ah, yes, it has to be infrared; otherwise it'll kick an electron into a higher energy state, or do something with rotational quantum states.


"Heads on a science
Apart" - Coldplay, The Scientist

IBdaMann wrote:
No, science doesn't insist that, ergo I don't insist that.

I am the Ninja Scientist! Beware!
16-10-2016 00:01
Into the NightProfile picture★★★★★
(9582)
jwoodward48 wrote:
Into the Night wrote:
jwoodward48 wrote:
Into the Night wrote:
Surface Detail wrote:
Into the Night wrote:
Whatever is absorbed is emitted at the same frequency, if it emitted at all.

If that were so, the Earth would be visibly glowing like a faint sun as it emitted all the solar radiation that it had absorbed. So it obviously isn't so.


Why would it?


The Earth absorbs solar radiation. It emits... not solar radiation. The Earthly radiation is incredibly different from solar radiation.


Each atom

Wouldn't that be each molecule?

No real difference for these purposes. Molecules have their absorption spectra, just like atoms.
jwoodward48 wrote:
that makes up the Earth absorbs it's favorite frequency of light.

The absorption spectrum for a single atom can include multiple wavelengths, but yes.
When (and if) the photon is emitted again, that will be emitted at the same frequency.

Yes.
Remember the photon need not be emitted at all. The energy of that emission follows Planck's law. It will be dependent on the temperature of the material.

???

The energy of a photon is solely dependent on its frequency/wavelength.

For an individual photon, yes. The difference is the number of photons emitted per second.
jwoodward48 wrote:
The combined effect of all the atoms of the Earth (or even a smaller chunk of it) doing this is to produce the so-called 'black body' type curve.

Let's suppose that an iron bar is heated by a heat lamp, at a single wavelength. What wavelength will the black body radiation be from the iron?

IF the iron is heated at that particular wavelength at all, each atom will emit the same wavelength.

Like everyone tooting their own horn at once in an orchestra, however, the result will be cacophony. In light, this broadens the wavelengths emitted. If each member of the orchestra is basically sitting in their own chair on the same stage, the cacophony is most pronounced. This is like what happens in a solid.

If each member of the orchestra is able to walk around the theater as they play, it is not so pronounced. You can hear an individual horn there, another one close by, etc. You can start to determine individual horns. This is like what happens in a liquid. The individual spectra are now quite visible, but there is some broadening still going on around them.

If you give each member the ability to fly around the theater (and this ability didn't make any noise), the cacophony is even less pronounced. You can hear individual horns as they go flying past. It's easy to determine who is playing at the time, because now you've added height to help make that determination. This is like gases. The individual spectra are now clearly visible and sharply defined.

The more people playing their horns, the louder it all gets. This is the total 'energy' of the orchestra per second. The number of photons per second. Shifting the analogy for a moment, the number of people playing is like temperature. The number of toots possible per second increases.

An individual is only playing one note at a time. The energy of one single photon, at that note (or individual spectral line). But the orchestra taken as a whole, determines the total energy per second.

To now relate temperature to the energy of an individual member without changing the size of the orchestra, consider you, sitting in you seat, being affected by players both near and far. Ones that are closer to you are louder than ones that are further away when they toot their horns. The more rapidly they move, the more often a player will be near you when they toot their horn (which takes a fixed amount of time).

While this analogy has a few holes (and is noisy!), it can help build a better picture of why Planck's law still applies even with a liquids and gases, and why line spectra blur with liquids and much more so with solids. The line spectra are still there, even in a solid. But this blurring effect can mask a lot of what you see.

Gases, for example, have convection when you heat them. Getting them to glow like a solid is a LOT harder because the gas is so effective at carrying the heat away. If you work at it hard enough, you can do it though. You have to increase the number of 'horn players' or molecules per square foot to get the blurring effect too.

Plank's law takes into account the note each horn player is playing, and the effect of the how fast each horn player is moving around. The result is how often you will hear that note per second, given as number of 'hits' per second over a certain amount of space (the theater).

If you consider ALL notes, including the blurring effect, you will get a curve like you typically see around Planck's law discussions. The difference between considering one note or all notes is the domain we keep going on about.

(There is another kind of domain that we've briefly touched without actually mentioning it, but that is another discussion and has nothing to do with the kind of domain we are using here.)

Hope this helps visualize it better.


The Parrot Killer
16-10-2016 01:56
jwoodward48
★★★★☆
(1537)
Into the Night wrote:
jwoodward48 wrote:
Into the Night wrote:
jwoodward48 wrote:
Into the Night wrote:
Surface Detail wrote:
Into the Night wrote:
Whatever is absorbed is emitted at the same frequency, if it emitted at all.

If that were so, the Earth would be visibly glowing like a faint sun as it emitted all the solar radiation that it had absorbed. So it obviously isn't so.


Why would it?


The Earth absorbs solar radiation. It emits... not solar radiation. The Earthly radiation is incredibly different from solar radiation.


Each atom

Wouldn't that be each molecule?

No real difference for these purposes. Molecules have their absorption spectra, just like atoms.

Ah, okay.
jwoodward48 wrote:
that makes up the Earth absorbs it's favorite frequency of light.

The absorption spectrum for a single atom can include multiple wavelengths, but yes.
When (and if) the photon is emitted again, that will be emitted at the same frequency.

Yes.
Remember the photon need not be emitted at all. The energy of that emission follows Planck's law. It will be dependent on the temperature of the material.

???

The energy of a photon is solely dependent on its frequency/wavelength.

For an individual photon, yes. The difference is the number of photons emitted per second.

Ah, okay, the energy of the overall emission of the substance, not the energy of the photon itself.
jwoodward48 wrote:
The combined effect of all the atoms of the Earth (or even a smaller chunk of it) doing this is to produce the so-called 'black body' type curve.

Let's suppose that an iron bar is heated by a heat lamp, at a single wavelength. What wavelength will the black body radiation be from the iron?

IF the iron is heated at that particular wavelength at all, each atom will emit the same wavelength.

Like everyone tooting their own horn at once in an orchestra, however, the result will be cacophony. In light, this broadens the wavelengths emitted. If each member of the orchestra is basically sitting in their own chair on the same stage, the cacophony is most pronounced. This is like what happens in a solid.

If each member of the orchestra is able to walk around the theater as they play, it is not so pronounced. You can hear an individual horn there, another one close by, etc. You can start to determine individual horns. This is like what happens in a liquid. The individual spectra are now quite visible, but there is some broadening still going on around them.

If you give each member the ability to fly around the theater (and this ability didn't make any noise), the cacophony is even less pronounced. You can hear individual horns as they go flying past. It's easy to determine who is playing at the time, because now you've added height to help make that determination. This is like gases. The individual spectra are now clearly visible and sharply defined.

The more people playing their horns, the louder it all gets. This is the total 'energy' of the orchestra per second. The number of photons per second. Shifting the analogy for a moment, the number of people playing is like temperature. The number of toots possible per second increases.

An individual is only playing one note at a time. The energy of one single photon, at that note (or individual spectral line). But the orchestra taken as a whole, determines the total energy per second.

To now relate temperature to the energy of an individual member without changing the size of the orchestra, consider you, sitting in you seat, being affected by players both near and far. Ones that are closer to you are louder than ones that are further away when they toot their horns. The more rapidly they move, the more often a player will be near you when they toot their horn (which takes a fixed amount of time).

While this analogy has a few holes (and is noisy!), it can help build a better picture of why Planck's law still applies even with a liquids and gases, and why line spectra blur with liquids and much more so with solids. The line spectra are still there, even in a solid. But this blurring effect can mask a lot of what you see.

Gases, for example, have convection when you heat them. Getting them to glow like a solid is a LOT harder because the gas is so effective at carrying the heat away. If you work at it hard enough, you can do it though. You have to increase the number of 'horn players' or molecules per square foot to get the blurring effect too.

Plank's law takes into account the note each horn player is playing, and the effect of the how fast each horn player is moving around. The result is how often you will hear that note per second, given as number of 'hits' per second over a certain amount of space (the theater).

If you consider ALL notes, including the blurring effect, you will get a curve like you typically see around Planck's law discussions. The difference between considering one note or all notes is the domain we keep going on about.

(There is another kind of domain that we've briefly touched without actually mentioning it, but that is another discussion and has nothing to do with the kind of domain we are using here.)

Hope this helps visualize it better.


Thanks. I have a few questions, though:

Infrared radiation can heat things up, right? And the temperature increase from a heat lamp is indistinguishable from the temperature increase from a conduction heat source, AFAIK. So why would one result in a continuous spectrum, while the other doesn't?

I thought that I had read somewhere about multiple molecules jumping up and down quantum states together, and that this could only be done in solids (or maybe liquids too?). Do you know what I'm talking about? If this is true, then it could play a role in the difference between solids and gases for the purpose of emission.



How is this explained with domains? It's a deuterium lamp, so only one substance.


"Heads on a science
Apart" - Coldplay, The Scientist

IBdaMann wrote:
No, science doesn't insist that, ergo I don't insist that.

I am the Ninja Scientist! Beware!
16-10-2016 12:06
Into the NightProfile picture★★★★★
(9582)
jwoodward48 wrote:
Thanks. I have a few questions, though:

Glad I could help to clarify it.
jwoodward48 wrote:
Infrared radiation can heat things up, right? And the temperature increase from a heat lamp is indistinguishable from the temperature increase from a conduction heat source, AFAIK. So why would one result in a continuous spectrum, while the other doesn't?

This question is insufficiently specified. Are you talking about a solid, liquid, or gas?
jwoodward48 wrote:
I thought that I had read somewhere about multiple molecules jumping up and down quantum states together, and that this could only be done in solids (or maybe liquids too?). Do you know what I'm talking about? If this is true, then it could play a role in the difference between solids and gases for the purpose of emission.

Don't see why that would make any different for any state of matter.

jwoodward48 wrote:
How is this explained with domains? It's a deuterium lamp, so only one substance.

Doesn't matter if it's one substance or a combination of substances. This particular type of lamp is designed to put out lots of UV light, done as an arc. Such arcs put out a lot of randomly organized energy. This is high energy light, capable of destroying bonds in molecules and even ionizing atoms.

The reasonably smooth looking spectrum curve is due to this random arc behavior. Arc powered devices essentially cause that blurring effect. They also tend toward the UV side of the spectrum, so caution must be exercised around arc lamps.

Although the curve doesn't naturally look it, if you examine the spikes in produced power, you will see their tops follow a Planck's law curve. The domain of the Planck's law curve, when intersected with the domain of this particular lamp output (as some kind of 'unknown' function), produce the relationship.
16-10-2016 17:13
jwoodward48
★★★★☆
(1537)
Into the Night wrote:
jwoodward48 wrote:
Thanks. I have a few questions, though:

Glad I could help to clarify it.
jwoodward48 wrote:
Infrared radiation can heat things up, right? And the temperature increase from a heat lamp is indistinguishable from the temperature increase from a conduction heat source, AFAIK. So why would one result in a continuous spectrum, while the other doesn't?

This question is insufficiently specified. Are you talking about a solid, liquid, or gas?

Sorry, a solid.
jwoodward48 wrote:
I thought that I had read somewhere about multiple molecules jumping up and down quantum states together, and that this could only be done in solids (or maybe liquids too?). Do you know what I'm talking about? If this is true, then it could play a role in the difference between solids and gases for the purpose of emission.

Don't see why that would make any different for any state of matter.

Don't gases have different emission spectra from solids? Never mind, I suppose it could just be density.

jwoodward48 wrote:
How is this explained with domains? It's a deuterium lamp, so only one substance.

Doesn't matter if it's one substance or a combination of substances. This particular type of lamp is designed to put out lots of UV light, done as an arc. Such arcs put out a lot of randomly organized energy. This is high energy light, capable of destroying bonds in molecules and even ionizing atoms.

The reasonably smooth looking spectrum curve is due to this random arc behavior. Arc powered devices essentially cause that blurring effect. They also tend toward the UV side of the spectrum, so caution must be exercised around arc lamps.

Although the curve doesn't naturally look it, if you examine the spikes in produced power, you will see their tops follow a Planck's law curve. The domain of the Planck's law curve, when intersected with the domain of this particular lamp output (as some kind of 'unknown' function), produce the relationship.


Ahh, that's the other domain you were talking about. Okay.


"Heads on a science
Apart" - Coldplay, The Scientist

IBdaMann wrote:
No, science doesn't insist that, ergo I don't insist that.

I am the Ninja Scientist! Beware!
16-10-2016 19:48
Into the NightProfile picture★★★★★
(9582)
jwoodward48 wrote:
Into the Night wrote:
jwoodward48 wrote:
Thanks. I have a few questions, though:

Glad I could help to clarify it.
jwoodward48 wrote:
Infrared radiation can heat things up, right? And the temperature increase from a heat lamp is indistinguishable from the temperature increase from a conduction heat source, AFAIK. So why would one result in a continuous spectrum, while the other doesn't?

This question is insufficiently specified. Are you talking about a solid, liquid, or gas?

Sorry, a solid.

In such a case, the blurring of emitted light into the something more like the 'traditional' black body curve works both ways. Absorption too, also works that way. It's just harder to imagine an orchestra 'sucking' horn toots from the listener.
jwoodward48 wrote:
jwoodward48 wrote:
I thought that I had read somewhere about multiple molecules jumping up and down quantum states together, and that this could only be done in solids (or maybe liquids too?). Do you know what I'm talking about? If this is true, then it could play a role in the difference between solids and gases for the purpose of emission.

Don't see why that would make any different for any state of matter.

Don't gases have different emission spectra from solids? Never mind, I suppose it could just be density.

jwoodward48 wrote:
How is this explained with domains? It's a deuterium lamp, so only one substance.

Doesn't matter if it's one substance or a combination of substances. This particular type of lamp is designed to put out lots of UV light, done as an arc. Such arcs put out a lot of randomly organized energy. This is high energy light, capable of destroying bonds in molecules and even ionizing atoms.

The reasonably smooth looking spectrum curve is due to this random arc behavior. Arc powered devices essentially cause that blurring effect. They also tend toward the UV side of the spectrum, so caution must be exercised around arc lamps.

Although the curve doesn't naturally look it, if you examine the spikes in produced power, you will see their tops follow a Planck's law curve. The domain of the Planck's law curve, when intersected with the domain of this particular lamp output (as some kind of 'unknown' function), produce the relationship.


Ahh, that's the other domain you were talking about. Okay.


Yes. That's the other domain I was talking about. We've recently touched upon another kind of domain that was unmentioned, but that had more to do with random number theory and axioms of mathematics.


The Parrot Killer
17-10-2016 15:43
IBdaMannProfile picture★★★★★
(4920)
jwoodward48 wrote: The atmosphere absorbs some radiation, right?

Yes, the atmosphere causes a change of form of energy.

jwoodward48 wrote: Which direction does that radiation go?

* facepalm * So we're back to "direction" again. You want to show that the right "direction" of energy somehow creates more energy (in the form of increased temperature).

Let's just call this direction the jwoodward48 direction. According to science, energy traveling in the jwoodward48 direction increases according to what equation?

.


Global Warming: The preferred religion of the scientifically illiterate.

Printing dollars to pay debt doesn't increase the number of dollars. - keepit

When the alt-physics birds sing about "indivisible bodies," we've got pure BS. - VernerHornung

Ah the "Valid Data" myth of ITN/IBD. - tmiddles

Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn

You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist.

The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank

:*sigh* Not the "raw data" crap. - Leafsdude

IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist
17-10-2016 17:53
jwoodward48
★★★★☆
(1537)
IBdaMann wrote:
jwoodward48 wrote: The atmosphere absorbs some radiation, right?

Yes, the atmosphere causes a change of form of energy.

jwoodward48 wrote: Which direction does that radiation go?

* facepalm * So we're back to "direction" again. You want to show that the right "direction" of energy somehow creates more energy (in the form of increased temperature).

Let's just call this direction the jwoodward48 direction. According to science, energy traveling in the jwoodward48 direction increases according to what equation?

.


It does create more energy - from a particular perspective.

Let's imagine if I was shining a flashlight at a toad. Then some arsehole sticks a mirror in between the flashlight and the toad. Now the light is in my eyes, and not on the toad. No energy was created, but there is more energy hitting my eyes.


"Heads on a science
Apart" - Coldplay, The Scientist

IBdaMann wrote:
No, science doesn't insist that, ergo I don't insist that.

I am the Ninja Scientist! Beware!
17-10-2016 20:45
IBdaMannProfile picture★★★★★
(4920)
jwoodward48 wrote: Let's imagine if I was shining a flashlight at a toad. Then some arsehole sticks a mirror in between the flashlight and the toad. Now the light is in my eyes, and not on the toad. No energy was created, but there is more energy hitting my eyes.

...and the earth is still at the same average global temperature, ergo there is still the same total amount of energy, regardless of perspective, yes?


.


Global Warming: The preferred religion of the scientifically illiterate.

Printing dollars to pay debt doesn't increase the number of dollars. - keepit

When the alt-physics birds sing about "indivisible bodies," we've got pure BS. - VernerHornung

Ah the "Valid Data" myth of ITN/IBD. - tmiddles

Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn

You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist.

The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank

:*sigh* Not the "raw data" crap. - Leafsdude

IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist
17-10-2016 22:27
jwoodward48
★★★★☆
(1537)
But that is assuming that the Earth is at the same average temperature.

I suppose that "system" is a better word than "perspective".
18-10-2016 22:30
IBdaMannProfile picture★★★★★
(4920)
jwoodward48 wrote: But that is assuming that the Earth is at the same average temperature.

That's like saying "But that is assuming physics works like it should." The only way the temperature can change is for the amount of the energy to change by some nonzero amount. This requires energy to either be created or destroyed, which violates the 1st LoT.

Ergo your claim that there is some special direction of travel that causes energy to be created ... violates the 1st LoT.


.


Global Warming: The preferred religion of the scientifically illiterate.

Printing dollars to pay debt doesn't increase the number of dollars. - keepit

When the alt-physics birds sing about "indivisible bodies," we've got pure BS. - VernerHornung

Ah the "Valid Data" myth of ITN/IBD. - tmiddles

Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn

You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist.

The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank

:*sigh* Not the "raw data" crap. - Leafsdude

IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist
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