List,
Please help me with this physics question.
If one has a given cube, say 2 x 2 x 2 inches. And one has the choice of
aluminum, copper, or lead (just for an example). Will each store or hold the
same amount of BTUs or does the density make a difference?
IF the density makes a difference,
The heat capacity of an object is the "Heat Capacity" = M * Cp
M = Mass
Cp = Specific Heat (at constant pressure)
M = Vol * SG
SG = Specific Gravity ( = density/density of water)
So, Heat Capacity = Vol * SG * Cp
If you want to know how much heat is required to change tempo:
Heat = Vol * SG *
Thermal energy in metals are measured in 'pro kg'. The rest is just
calculation.
From a practical standpoint I would use copper. You can solder and weld
it more easely.
Look for how head-fin spreaders work for CPUs.
- Henry
Perry Sandeen schrieb:
List,
Please help me with this physics que
Most metals have a specific heat around .34, where water is 1.0. ( so .34 BTU
to raise a pound od aluminum by 1 deg F)
The have different densities, so on a per volume basis, you want dense.
Tungsten for instance or osmium
You also need to consider conductivity though. Gold is good
On Jan 27
If you are considering conductivity for dynamic reasons, the correct
figure of merit is "Thermal Diffusivity"
= (Specific Heat) / (Thermal Conductivity)
-John
=
> Most metals have a specific heat around .34, where water is 1.0. ( so .34
> BTU to raise a pound od aluminum by 1 deg F
At 04:18 PM 1/27/2011, J. Forster wrote...
If you are considering conductivity for dynamic reasons, the correct
figure of merit is "Thermal Diffusivity"
= (Specific Heat) / (Thermal Conductivity)
If you want a thermal mass to help control temperature swings, the more
heat capacity is good. Is
If you want the thermal mass to behave close to an isothermal body,
diffusivity is very important.
For example, a large mass of still water has high heat capacity, but poor
diffusivity. Much of the heat capacity is useless.
-John
==
> At 04:18 PM 1/27/2011, J. Forster wrote...
>>If
> If you want a thermal mass to help control temperature swings, the more
> heat capacity is good. Isn't more thermal conductivity also desired? It
> seems like a substance with low conductivity wouldn't gather/release heat
> well.
It depends on the time constant (frequency) of the thermal chan
On Thu, Jan 27, 2011 at 12:38 PM, Perry Sandeen wrote:
> List,
>
> Please help me with this physics question.
>
> If one has a given cube, say 2 x 2 x 2 inches. And one has the choice of
> aluminum, copper, or lead (just for an example). Will each store or hold the
> same amount of BTUs or doe
jim...@earthlink.net said:
> Most metals have a specific heat around .34, where water is 1.0. ( so .34
> BTU to raise a pound od aluminum by 1 deg F)
Where did you get that?
This table says:
Aluminum 0.215
Copper 0.092
Iron0.107
Lead0.031
http://phoenix.phys.clemson.edu/labs/2
At 05:33 PM 1/27/2011, J. Forster wrote...
If you want the thermal mass to behave close to an isothermal body,
diffusivity is very important.
For example, a large mass of still water has high heat capacity, but
poor
diffusivity. Much of the heat capacity is useless.
If the equation given ["T
I got the Thermal Diffusivity definition upside down.
-John
=
> At 05:33 PM 1/27/2011, J. Forster wrote...
>>If you want the thermal mass to behave close to an isothermal body,
>>diffusivity is very important.
>>
>>For example, a large mass of still water has high heat capacity, b
On 1/27/11 3:20 PM, Hal Murray wrote:
jim...@earthlink.net said:
Most metals have a specific heat around .34, where water is 1.0. ( so .34
BTU to raise a pound od aluminum by 1 deg F)
Where did you get that?
probably misremembering.. Standing in an airport terminal trying to
figure out whe
At 07:53 PM 1/27/2011, jimlux wrote...
I did do some googling and found this interesting statement in
Wikipedia
Another way of stating this, is that the volume-specific heat capacity
(volumetric heat capacity) of solid elements is roughly a constant.
I'll admit that I'm prone to citing Wikiped
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