Science > Physics > Conduction, Radiation, and Convection? Is that all there is?
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Science > Physics |
| User: |
"mm" |
| Date: |
17 Aug 2006 11:12:03 AM |
| Object: |
Conduction, Radiation, and Convection? Is that all there is? |
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?
Is that all there is? Is diffusion a fourth or is it subsumed by
convection?
I could be wrong but:
Conduction seems to be limited to within a solid, or from the surface
of a solid to that part of a liquid or gas in contact with the solid.
ICBWB:
Convection seems to be limited to liquids and gases.
And ICBWB: radiation seems to be limited to from a solid or maybe a
liquid through a gas to another solid or maybe a liquid.
As to convection, it was always described and seems to be limited to
broad currents, such as hot air rising and cold air sinking, but is
that all that happens? In, say, a room with moderate cooling in the
summer or moderate heating in the winter, while in general the hot air
rises, doesn't the random motion of some of the hot air cause it to go
downward and to mix with the cooler air below it? Is this radiation?
Is it still convection? Or is it diffusion and for reasons of
definition, not one of the other three?
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| User: "CWatters" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
18 Aug 2006 06:06:26 AM |
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"mm" <NOPSAMmm2005@bigfoot.com> wrote in message
news:1g49e2h3cs4q2jetihi4s0p3l8tkfm3jnj@4ax.com...
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?
Is that all there is? Is diffusion a fourth or is it subsumed by
convection?
How about some of the tricks used to achieve near absolute zero
temperatures. I recall they are quite exotic and involve lasers and optical
cavities and the like - but perhaps they all amount to conduction or
radaition?
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| User: "zero" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
17 Aug 2006 11:39:28 AM |
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"mm" > wrote in message .
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?
Is that all there is? Is diffusion a fourth or is it subsumed by
convection?
Transporter beam in a pinch or properly used, a Deflector Dish.
http://www.ccdump.org/deflectordish.html
HTH,
-zero
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| User: "Pat" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
17 Aug 2006 12:05:30 PM |
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Time travel, too. You could go back to before the heat.
For adding heat, don't forget laser beams, microwaves, and spontaneous
combustion :-))
zero wrote:
"mm" > wrote in message .
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?
Is that all there is? Is diffusion a fourth or is it subsumed by
convection?
Transporter beam in a pinch or properly used, a Deflector Dish.
http://www.ccdump.org/deflectordish.html
HTH,
-zero
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| User: "tadchem" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
17 Aug 2006 04:31:26 PM |
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Conduction: transfer of heat from one molecule to its neighbor by means
of thermal collisions.
Convection: transfer of heat from one location to another as kinetic
energy of a group of molecules of a fluid. (usually driven by the
effects of gravity on differential densities as in the Archimedes
effect)
Diffustion: *also* transfer of heat from one location to another as
kinetic energy of a group of molecules of a fluid. Distinguished from
convection in that the random thermal motion of the molecules provides
the transport.
Radiation: transfer of heat from location to another by means of
electromagnetic radiation. No medium is required as radiation can
traverse a total vacuum. [The sun sure is hot today, isn't it?] If a
medium is present it must be at least partially transparent to the
particular wavelengths of radiation involved.
Heat can also be transported by converting it to another form
(typically electrical or chemical energy) top be placed within a
material, which itself is transported (or in the case of electricity is
electrically conducted) to another location where the heat can be
released.
HTH
Tom Davidson
Richmond, VA
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| User: "Stormin Mormon" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
18 Aug 2006 08:51:11 AM |
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I could be wrong but:
Conduction seems to be limited to within a solid, or from the surface
of a solid to that part of a liquid or gas in contact with the solid.
CY: I'd think that conduction is possible within gasses,b ut much less
so. Cause they would be more likely to convect.
ICBWB:
Convection seems to be limited to liquids and gases.
CY: Well, if you wanted to be a smartass, you could mention a
semiliquid like sand. But that's not really fair.
And ICBWB: radiation seems to be limited to from a solid or maybe a
liquid through a gas to another solid or maybe a liquid.
CY: Sounds about right. Of course, radiation from the sun is supposed
to be a superhot ball of gas (plasma??)
As to convection, it was always described and seems to be limited to
broad currents, such as hot air rising and cold air sinking, but is
that all that happens? In, say, a room with moderate cooling in the
summer or moderate heating in the winter, while in general the hot air
rises, doesn't the random motion of some of the hot air cause it to go
downward and to mix with the cooler air below it?
CY: yes, that would happen. Some air currents push hot air down.
Is this radiation?
CY: No.
Is it still convection?
CY: Pushing hot air down is still convection.
Or is it diffusion and for reasons of
definition, not one of the other three?
CY: Only three ways I know to transfer heat.
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| User: "CWatters" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
18 Aug 2006 11:57:56 AM |
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"Stormin Mormon" <cayoung61-&spamblock*-@hotmail.com> wrote in message
news:jBjFg.18320$uH6.5761@twister.nyroc.rr.com...
I could be wrong but:
Conduction seems to be limited to within a solid, or from the surface
of a solid to that part of a liquid or gas in contact with the solid.
CY: I'd think that conduction is possible within gasses,b ut much less
so. Cause they would be more likely to convect.
Take a look at sealed double glazing.... The gap between the panes is
choosen so that it's as large as possible (to mimimise conduction losses)
but not so big that it allows convection losses.
It's worth noting that convection is only an issue because conduction occurs
between the gas and glass. If there was no such conduction it wouldn't
matter if the gas had convective flow.
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| User: "David Combs" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
16 Sep 2006 04:27:37 PM |
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In article <1g49e2h3cs4q2jetihi4s0p3l8tkfm3jnj@4ax.com>,
mm <NOPSAMmm2005@bigfoot.com> wrote:
....
And ICBWB: radiation seems to be limited to from a solid or maybe a
liquid through a gas to another solid or maybe a liquid.
....
Nope -- no "ether" or anything else required for radiation
to travel through (eg, onto you).
It's "electromagnetic" radiation, exactly the same as for
light from a candle or light-bulb or flourescent light, heat
and light from the sun, or radio or tv transmitting-antenna.
Travels best, and even fastest, through a vacuum.
Cheers!
David
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| User: "Keith Williams" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
17 Aug 2006 11:43:58 AM |
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In article <1g49e2h3cs4q2jetihi4s0p3l8tkfm3jnj@4ax.com>,
NOPSAMmm2005@bigfoot.com says...
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?
Is that all there is? Is diffusion a fourth or is it subsumed by
convection?
I'd say conduction, rather then convection. Heat is transfered by
the molecules bouncing off each other = conduction.
I could be wrong but:
Conduction seems to be limited to within a solid, or from the surface
of a solid to that part of a liquid or gas in contact with the solid.
No, liquids and gases also conduct. Convection may be dominant
though.
ICBWB:
Convection seems to be limited to liquids and gases.
Sure, something's gotta move for convection. Solids don't move too
well. ;-)
And ICBWB: radiation seems to be limited to from a solid or maybe a
liquid through a gas to another solid or maybe a liquid.
No, radiation occurs with all substances but at moderate
temperatures can be dwarfed by conduction and convection. We see
Jupiter (a "gas giant") by radiation, for instance.
As to convection, it was always described and seems to be limited to
broad currents, such as hot air rising and cold air sinking, but is
that all that happens? In, say, a room with moderate cooling in the
summer or moderate heating in the winter, while in general the hot air
rises, doesn't the random motion of some of the hot air cause it to go
downward and to mix with the cooler air below it? Is this radiation?
Some by radiation, some by conduction, mostly convection though.
Is it still convection? Or is it diffusion and for reasons of
definition, not one of the other three?
Diffusion normally relates to different gases/liquids. If they're
the same I'm not sure how you track the molecules. They'll swap
heat by bumping into each other (conduction).
--
Keith
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| User: "z" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
17 Aug 2006 02:50:04 PM |
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Keith Williams wrote:
In article <1g49e2h3cs4q2jetihi4s0p3l8tkfm3jnj@4ax.com>,
NOPSAMmm2005@bigfoot.com says...
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?
Is that all there is? Is diffusion a fourth or is it subsumed by
convection?
I'd say conduction, rather then convection. Heat is transfered by
the molecules bouncing off each other = conduction.
depends what's diffusing. If it's just the heat, that's conduction. if
it's hot molecules diffusing, that's convection.
I could be wrong but:
Conduction seems to be limited to within a solid, or from the surface
of a solid to that part of a liquid or gas in contact with the solid.
No, liquids and gases also conduct. Convection may be dominant
though.
ICBWB:
Convection seems to be limited to liquids and gases.
Sure, something's gotta move for convection. Solids don't move too
well. ;-)
And ICBWB: radiation seems to be limited to from a solid or maybe a
liquid through a gas to another solid or maybe a liquid.
No, radiation occurs with all substances but at moderate
temperatures can be dwarfed by conduction and convection. We see
Jupiter (a "gas giant") by radiation, for instance.
As to convection, it was always described and seems to be limited to
broad currents, such as hot air rising and cold air sinking, but is
that all that happens? In, say, a room with moderate cooling in the
summer or moderate heating in the winter, while in general the hot air
rises, doesn't the random motion of some of the hot air cause it to go
downward and to mix with the cooler air below it? Is this radiation?
Some by radiation, some by conduction, mostly convection though.
Is it still convection? Or is it diffusion and for reasons of
definition, not one of the other three?
Diffusion normally relates to different gases/liquids. If they're
the same I'm not sure how you track the molecules. They'll swap
heat by bumping into each other (conduction).
--
Keith
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| User: "krw" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
18 Aug 2006 10:28:14 AM |
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In article <1155844204.397885.104130@i42g2000cwa.googlegroups.com>,
gzuckier@snail-mail.net says...
Keith Williams wrote:
In article <1g49e2h3cs4q2jetihi4s0p3l8tkfm3jnj@4ax.com>,
NOPSAMmm2005@bigfoot.com says...
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?
Is that all there is? Is diffusion a fourth or is it subsumed by
convection?
I'd say conduction, rather then convection. Heat is transfered by
the molecules bouncing off each other = conduction.
depends what's diffusing. If it's just the heat, that's conduction. if
it's hot molecules diffusing, that's convection.
I disagree. How do you track which molecule is which? Convection
would only allow hotter molecules to rise (and colder sink).
Diffusion would allow the reverse too. As such, diffusion may be a
fourth mechanism but it's not likely to be significant as the
molecules transfer heat by conduction to each other.
--
Keith
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| User: "mm" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
19 Aug 2006 12:42:37 PM |
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On Thu, 17 Aug 2006 12:43:58 -0400, Keith Williams <krw@att.bizzzz>
wrote:
As to convection, it was always described and seems to be limited to
broad currents, such as hot air rising and cold air sinking, but is
that all that happens? In, say, a room with moderate cooling in the
summer or moderate heating in the winter, while in general the hot air
rises, doesn't the random motion of some of the hot air cause it to go
downward and to mix with the cooler air below it? Is this radiation?
Some by radiation, some by conduction, mostly convection though.
Is it still convection? Or is it diffusion and for reasons of
definition, not one of the other three?
Diffusion normally relates to different gases/liquids. If they're
the same I'm not sure how you track the molecules.
Can't they tie little transmitters to them, like they do with wild
animals?
I guess not.
They'll swap
heat by bumping into each other (conduction).
I guessed radiation and convection and you and most of you said it's
conduction, the only one I iddn't guess. Oh, well.
Thanks to you and everyone (except the trekkies ;) )
I didn't answer right away because I read alt.home.repair and it has
so much traffic, I missed the whole thread for 2 days (until I
remembered to go looking for it.)
--
Keith
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| User: "Stormin Mormon" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
18 Aug 2006 08:51:11 AM |
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Yes, convection stands there with her high heels, black leather and
whip. She says to the conduction which is tied to the bed.....
Know what you mean, though. Since fluids vary in density with temp,
that convection would be more a factor.
--
Christopher A. Young
You can't shout down a troll.
You have to starve them.
..
"Keith Williams" <krw@att.bizzzz> wrote in message
news:MPG.1f4e638cd339fbed989c4f@News.Individual.NET...
I could be wrong but:
Conduction seems to be limited to within a solid, or from the
surface
of a solid to that part of a liquid or gas in contact with the
solid.
No, liquids and gases also conduct. Convection may be dominant
though.
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| User: "" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
17 Aug 2006 11:27:48 AM |
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In article <1g49e2h3cs4q2jetihi4s0p3l8tkfm3jnj@4ax.com>, mm <NOPSAMmm2005@bigfoot.com> writes:
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?
Is that all there is? Is diffusion a fourth or is it subsumed by
convection?
Diffusion is conduction.
I could be wrong but:
Conduction seems to be limited to within a solid, or from the surface
of a solid to that part of a liquid or gas in contact with the solid.
No, conduction is present in liquids and gases as well, though it is
dominated by convection for significant temperature gradients (and in
the presence of gravity).
ICBWB:
Convection seems to be limited to liquids and gases.
That much is certainly true.
And ICBWB: radiation seems to be limited to from a solid or maybe a
liquid through a gas to another solid or maybe a liquid.
In principle radiation can be present within liquid or solid as well.
In practice, under normal circumstances, its range is so limited there
that it is indistinguishable from conduction.
As to convection, it was always described and seems to be limited to
broad currents, such as hot air rising and cold air sinking, but is
that all that happens? In, say, a room with moderate cooling in the
summer or moderate heating in the winter, while in general the hot air
rises, doesn't the random motion of some of the hot air cause it to go
downward and to mix with the cooler air below it? Is this radiation?
Is it still convection? Or is it diffusion and for reasons of
definition, not one of the other three?
Collective motion of masses of air is convection, random motion of
individual molecules is conduction.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
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| User: "" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
17 Aug 2006 02:34:20 PM |
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mm <NOPSAMmm2005@bigfoot.com> wrote:
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?
Is that all there is? Is diffusion a fourth or is it subsumed by
convection?
It's a part of conduction. Some people also add "phase change" as
a method of heat transfer, eg evaporation from lower soil layers
and condensation above.
As to convection, it was always described and seems to be limited to
broad currents, such as hot air rising and cold air sinking, but is
that all that happens? In, say, a room with moderate cooling in the
summer or moderate heating in the winter, while in general the hot air
rises, doesn't the random motion of some of the hot air cause it to go
downward and to mix with the cooler air below it?
Not much. Then again, room air may fall near an outside wall, slide
across the floor, rise up near an inside wall, then slide across
the ceiling to make a loop.
Is this radiation?
No, but that can also be important. Surfaces with mean absolute temp T (R)
and emissivity 1 have a linearized radiation conductance 4x0.1714x10^8xT^3
Btu/h-F-ft^2, eg U1 (R1) for T = 400 + 70 (F.) = 530 R.
Nick
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| User: "Neill Massello" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
18 Aug 2006 11:59:12 AM |
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mm <NOPSAMmm2005@bigfoot.com> wrote:
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?
Is that all there is? Is diffusion a fourth or is it subsumed by
convection?
<http://en.wikipedia.org/wiki/Heat#Heat_transfer_mechanisms>
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| User: "Edward Green" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
19 Aug 2006 06:45:22 PM |
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Neill Massello wrote:
mm <NOPSAMmm2005@bigfoot.com> wrote:
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?
Is that all there is? Is diffusion a fourth or is it subsumed by
convection?
<http://en.wikipedia.org/wiki/Heat#Heat_transfer_mechanisms>
The're fools, damn fools, and those who post replies whose sole content
is links to wikipedia articles.
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| User: "dpb" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
21 Aug 2006 01:37:45 PM |
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mm wrote:
....
As to convection, it was always described and seems to be limited to
broad currents, such as hot air rising and cold air sinking, ...
That's _natural_ convection, there's also _forced_ convection.
Difference is whether there is an external causative factor for the
fluid motion (fan, say) or only the thermal gradient.
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| User: "Igor" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
17 Aug 2006 12:05:02 PM |
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mm wrote:
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?
Is that all there is?
That's about it. At least that's what's still being taught at all
levels, these days.
Is diffusion a fourth or is it subsumed by
convection?
Depends what you actually mean by diffusion. If you're talking about
the ability of a gas to spread out to fill it's container, then yes,
you're talking convection.
I could be wrong but:
Conduction seems to be limited to within a solid, or from the surface
of a solid to that part of a liquid or gas in contact with the solid.
Conduction can occur in any medium. Remember it's just the direct
transfer of heat energy through the media.
ICBWB:
Convection seems to be limited to liquids and gases.
In normal, everyday situations, yes. But geologists talk about
convection in rock in the earth's mantle, albeit very hot rock, but
still technically a solid at the pressures considered.
And ICBWB: radiation seems to be limited to from a solid or maybe a
liquid through a gas to another solid or maybe a liquid.
Well, radiation can be generated in any medium and absorbed by any
medium, regardless of state.
As to convection, it was always described and seems to be limited to
broad currents, such as hot air rising and cold air sinking, but is
that all that happens?
Basically. Convection is the transfer of heat by a moving medium, such
as air.
In, say, a room with moderate cooling in the
summer or moderate heating in the winter, while in general the hot air
rises, doesn't the random motion of some of the hot air cause it to go
downward and to mix with the cooler air below it?
Statistically yes, but on average, warm air will rise and cooler air
will fall. It is thermodynamically possible for the very opposite to
occur, but the probability of that happening is astronomically small.
Is this radiation?
Radiation is light, UV, IR, etc.
Is it still convection?
In your above example, it is practically all convection, since the air
is moving and carrying the heat with it. There could also be some
conduction occuring, as energy is directly transferred through the air
between hot and cold regions,.and perhaps some radiation if sunlight is
shining through a window or there is a light turned on.
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| User: "z" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
17 Aug 2006 02:48:42 PM |
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mm wrote:
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?
Is that all there is? Is diffusion a fourth or is it subsumed by
convection?
Ah, you have forgotten the frequently seen fourth form, which is
wrapping the hot thing up in a towel and running with it over to
somewhere else where you drop it off. It can move a lot of heat very
effectively.
I could be wrong but:
Conduction seems to be limited to within a solid, or from the surface
of a solid to that part of a liquid or gas in contact with the solid.
ICBWB:
Convection seems to be limited to liquids and gases.
And ICBWB: radiation seems to be limited to from a solid or maybe a
liquid through a gas to another solid or maybe a liquid.
As to convection, it was always described and seems to be limited to
broad currents, such as hot air rising and cold air sinking, but is
that all that happens? In, say, a room with moderate cooling in the
summer or moderate heating in the winter, while in general the hot air
rises, doesn't the random motion of some of the hot air cause it to go
downward and to mix with the cooler air below it? Is this radiation?
Is it still convection? Or is it diffusion and for reasons of
definition, not one of the other three?
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| User: "" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
17 Aug 2006 03:57:18 PM |
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Ah, you have forgotten the frequently seen fourth form, which is
wrapping the hot thing up in a towel and running with it over to
somewhere else where you drop it off. It can move a lot of heat very
effectively.
Isn't that convection?
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| User: "z" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
18 Aug 2006 12:41:43 PM |
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wrote:
Ah, you have forgotten the frequently seen fourth form, which is
wrapping the hot thing up in a towel and running with it over to
somewhere else where you drop it off. It can move a lot of heat very
effectively.
Isn't that convection?
Twice arrested, never convected.
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| User: "Edward Green" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
18 Aug 2006 05:45:43 PM |
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z wrote:
Ah, you have forgotten the frequently seen fourth form, which is
wrapping the hot thing up in a towel and running with it over to
somewhere else where you drop it off. It can move a lot of heat very
effectively.
Very good! That's non-convective mixing or mass-transport (to give it
some important sounding names).
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| User: "z" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
19 Aug 2006 11:12:39 AM |
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Edward Green wrote:
z wrote:
Ah, you have forgotten the frequently seen fourth form, which is
wrapping the hot thing up in a towel and running with it over to
somewhere else where you drop it off. It can move a lot of heat very
effectively.
Very good! That's non-convective mixing or mass-transport (to give it
some important sounding names).
Actually, reminds me of the early days of networking, when one of the
fastest protocols was still sneakernet. I.e., copy a floppy full and
run it over to the other machine, thereby transferring 1.4 meg
relatively quickly.
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| User: "" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
21 Aug 2006 12:24:55 PM |
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On 19 Aug 2006 09:12:39 -0700, "z" <gzuckier@snail-mail.net> wrote:
Actually, reminds me of the early days of networking, when one of the
fastest protocols was still sneakernet. I.e., copy a floppy full and
run it over to the other machine, thereby transferring 1.4 meg
relatively quickly.
I used to do that but we used SCSI drives. I still have a couple 9 gig
Elites in AS/400 shoeboxes that make an exccellent way to get a bunch
of gigs out to my MP3 player machines in the cars.
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| User: "Keith Williams" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
22 Aug 2006 09:25:05 AM |
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In article <8vqje2hfttsk1sc67t8asr0doed96hjqv5@4ax.com>,
gfretwell@aol.com says...
On 19 Aug 2006 09:12:39 -0700, "z" <gzuckier@snail-mail.net> wrote:
Actually, reminds me of the early days of networking, when one of the
fastest protocols was still sneakernet. I.e., copy a floppy full and
run it over to the other machine, thereby transferring 1.4 meg
relatively quickly.
I used to do that but we used SCSI drives. I still have a couple 9 gig
Elites in AS/400 shoeboxes that make an exccellent way to get a bunch
of gigs out to my MP3 player machines in the cars.
I bought an external USB to PATA/SATA enclosure and a 160GB drive
for such. Total cost; $60. Why throw anything away? ;-)
--
Keith
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| User: "Edward Green" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
19 Aug 2006 11:44:50 AM |
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z wrote:
Edward Green wrote:
z wrote:
Ah, you have forgotten the frequently seen fourth form, which is
wrapping the hot thing up in a towel and running with it over to
somewhere else where you drop it off. It can move a lot of heat very
effectively.
Very good! That's non-convective mixing or mass-transport (to give it
some important sounding names).
Actually, reminds me of the early days of networking, when one of the
fastest protocols was still sneakernet. I.e., copy a floppy full and
run it over to the other machine, thereby transferring 1.4 meg
relatively quickly.
Yes. And what do you mean 'early days'?
I am working for a very large company where, in my area, there are
still two non-communicating networks, and occasionally data is
transferred by sneaker net. Of course, this is going to be fixed any
day now...
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| User: "" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
20 Aug 2006 04:53:35 AM |
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In article <1156005889.948433.106800@m79g2000cwm.googlegroups.com>,
"Edward Green" <spamspamspam3@netzero.com> wrote:
z wrote:
Edward Green wrote:
z wrote:
Ah, you have forgotten the frequently seen fourth form, which is
wrapping the hot thing up in a towel and running with it over to
somewhere else where you drop it off. It can move a lot of heat very
effectively.
Very good! That's non-convective mixing or mass-transport (to give it
some important sounding names).
Actually, reminds me of the early days of networking, when one of the
fastest protocols was still sneakernet. I.e., copy a floppy full and
run it over to the other machine, thereby transferring 1.4 meg
relatively quickly.
Yes. And what do you mean 'early days'?
Not very early. Tranferring bits on a _floppy_ is like
moving the Atlantic Ocean into the Pacific with a teaspoon.
I am working for a very large company where, in my area, there are
still two non-communicating networks, and occasionally data is
transferred by sneaker net. Of course, this is going to be fixed any
day now...
These days, with those cigarette lighters, it's not too difficult.
You don't need three muscled males, a skid, and 10000 magtapes to
do it.
/BAH
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| User: "Edward Green" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
20 Aug 2006 09:41:30 AM |
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wrote:
Not very early. Tranferring bits on a _floppy_ is like
moving the Atlantic Ocean into the Pacific with a teaspoon.
Sometimes all you need to move is a cup.
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| User: "krw" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
20 Aug 2006 10:33:38 AM |
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In article <ec9bev$8ss_002@s950.apx1.sbo.ma.dialup.rcn.com>,
jmfbahciv@aol.com says...
In article <1156005889.948433.106800@m79g2000cwm.googlegroups.com>,
"Edward Green" <spamspamspam3@netzero.com> wrote:
z wrote:
Edward Green wrote:
z wrote:
Ah, you have forgotten the frequently seen fourth form, which is
wrapping the hot thing up in a towel and running with it over to
somewhere else where you drop it off. It can move a lot of heat very
effectively.
Very good! That's non-convective mixing or mass-transport (to give it
some important sounding names).
Actually, reminds me of the early days of networking, when one of the
fastest protocols was still sneakernet. I.e., copy a floppy full and
run it over to the other machine, thereby transferring 1.4 meg
relatively quickly.
Yes. And what do you mean 'early days'?
Not very early. Tranferring bits on a _floppy_ is like
moving the Atlantic Ocean into the Pacific with a teaspoon.
I am working for a very large company where, in my area, there are
still two non-communicating networks, and occasionally data is
transferred by sneaker net. Of course, this is going to be fixed any
day now...
These days, with those cigarette lighters, it's not too difficult.
You don't need three muscled males, a skid, and 10000 magtapes to
do it.
Think about the bandwidth of a 747 full of magtapes! ;-)
--
Keith
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| User: "" |
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| Title: Re: Conduction, Radiation, and Convection? Is that all there is? |
21 Aug 2006 04:14:47 AM |
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In article <MPG.1f524adf87457f5c9898f0@news.individual.net>,
krw <krw@att.bizzzz> wrote:
In article <ec9bev$8ss_002@s950.apx1.sbo.ma.dialup.rcn.com>,
jmfbahciv@aol.com says...
In article <1156005889.948433.106800@m79g2000cwm.googlegroups.com>,
"Edward Green" <spamspamspam3@netzero.com> wrote:
z wrote:
Edward Green wrote:
z wrote:
Ah, you have forgotten the frequently seen fourth form, which is
wrapping the hot thing up in a towel and running with it over to
somewhere else where you drop it off. It can move a lot of heat very
effectively.
Very good! That's non-convective mixing or mass-transport (to give it
some important sounding names).
Actually, reminds me of the early days of networking, when one of the
fastest protocols was still sneakernet. I.e., copy a floppy full and
run it over to the other machine, thereby transferring 1.4 meg
relatively quickly.
Yes. And what do you mean 'early days'?
Not very early. Tranferring bits on a _floppy_ is like
moving the Atlantic Ocean into the Pacific with a teaspoon.
I am working for a very large company where, in my area, there are
still two non-communicating networks, and occasionally data is
transferred by sneaker net. Of course, this is going to be fixed any
day now...
These days, with those cigarette lighters, it's not too difficult.
You don't need three muscled males, a skid, and 10000 magtapes to
do it.
Think about the bandwidth of a 747 full of magtapes! ;-)
Dagnurbbit. Now you've got me hooked. Is this the capacity
of one of those cigarette lighters? ...and people long
for the good ol' days; not me.
/BAH
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