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Grex > Agora41 > #159: Two words you don't want to see used together: "nuclear" and "surprise" | |
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| 17 new of 66 responses total. |
rcurl
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response 50 of 66:
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Jun 5 16:16 UTC 2002 |
Pressure and temperature are separate, independent, thermodynamic variables.
Any single component, single phase, system, has only two (2) degrees
of freedom (this follows from the Gibbs Phase Rule). They can be any
(independent) pair, but two (2) are required to fix all other properties
of the system.
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bdh3
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response 51 of 66:
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Jun 8 07:37 UTC 2002 |
Are you familiar with how an H-bomb works?
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rcurl
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response 52 of 66:
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Jun 8 15:30 UTC 2002 |
Yes. What would you like to know?
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bru
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response 53 of 66:
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Jun 9 02:56 UTC 2002 |
I am, but only in the most general sense.
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flem
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response 54 of 66:
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Jun 10 16:59 UTC 2002 |
I like to flatter myself as being fairly familiar not only with how H- and
A-bombs work, but also with the history of their development, and I'm totally
at a loss to understand what beady is talking about in #49.
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mdw
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response 55 of 66:
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Jun 14 06:34 UTC 2002 |
Re #49 - pressure is usually measured in terms of force/area (um, that's
D/(M*T*T) where D=distance, M=mass, T=time.); heat is a form of energy
which is measured in terms of force x distance ((D*D*M)/(T*T)). In SI
that's the Pascal and the Joule, respectively.
To the best of my knowledge, Pascal and Joule both died before atomic
energy was theorized or proven, and well before the Rosenbergs.
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gull
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response 56 of 66:
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Jun 17 13:59 UTC 2002 |
Compressing something generally *creates* heat. I think that may be the
source of the confusion.
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rcurl
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response 57 of 66:
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Jun 17 14:27 UTC 2002 |
"Heat" is, technically, thermal (molecular vibration) energy being
transferred. Compression is "work", which is the transfer of
mechanical (or chemical or electrical) energy without dissipation
to thermal energy. If you compress most gases (not all) they will
get hotter, but no heat is created. If the compression is not
adiabatic, heat may transfer. There will be a quiz......
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orinoco
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response 58 of 66:
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Jun 17 14:48 UTC 2002 |
"They will get hotter, but no heat is created"
Eh? I think I know what you're trying to say, but what a terrible way of
phrasing it. Do you mean that the temperature will rise without the amount
of energy going up?
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rcurl
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response 59 of 66:
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Jun 17 15:46 UTC 2002 |
You have to understand that "heat" means only thermal energy being
transferred. It is only related to temperature by the properties of
the system and the substance. I put it the way I did to get your
attention on this point (which succeeded).
If you compress most (not all) gases adiabatically (with no heat - that
is, no transfer of thermal energy to the system), the temperature will go
up. No heat has been added. One cannot speak of "the heat has increased",
because heat is not a property, it is a process. The energy in the system
has gone up by the amount of work done in compressing the gas. That
energy was provided as work, however, not as heat. You can get that work
back by expanding the gas (and the temperature will go down again). So,
the gas is acting like a spring. However, no heat was involved.
This is part of the language of thermodynamics. Terms have very
specific meanings. "Heat" in the vernacular has many meanings.
I would judge that the meaning of "heat" was taken from the notion
of heating something (transferring thermal energy to it), and then
restricted to only that meaning, heat being the energy that is
transferrred.
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jp2
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response 60 of 66:
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Jun 17 15:56 UTC 2002 |
This response has been erased.
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mynxcat
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response 61 of 66:
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Jun 17 16:14 UTC 2002 |
This response has been erased.
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jp2
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response 62 of 66:
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Jun 17 16:17 UTC 2002 |
This response has been erased.
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mynxcat
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response 63 of 66:
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Jun 17 16:20 UTC 2002 |
This response has been erased.
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rcurl
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response 64 of 66:
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Jun 17 16:38 UTC 2002 |
Depending on how you interpret "create", you can create heat. That is, you
might say that you can "create" a transfer of thermal energy. A better
word would be "cause", and "make" just might do.
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russ
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response 65 of 66:
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Jun 17 17:18 UTC 2002 |
I agree with orinoco: in the case of compression, work is
definitely converted to heat. To convert the heat back into
work requires the reverse conversion, which is typically lossy
(and constitutes the central feature of a "heat engine").
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mdw
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response 66 of 66:
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Jun 22 06:14 UTC 2002 |
I can only presume jp2 never exercises, and for that matter, never
spends time in any environment != 98.6 degrees F.
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