What is it about copper that makes it so good as a conductor of heat?

Similar q. for silver and electricity.

Chemistry and valence electrons. Gold also. Do a google for "conductors".

Bob Swinney
"jtaylor" wrote in message
. ca...
What is it about copper that makes it so good as a conductor of heat?

Similar q. for silver and electricity.

Welcome to the world of physics and quantum mechanics! You might try
reading this: http://www.allaboutcircuits.com/vol_1/chpt_12/1.html or this:
http://www.physlink.com/Education/AskExperts/ae432.cfm or possibly even
this:
http://www.rare-earth-magnets.com/ma...insulators.htm

Carmine Castiglia
Got nonagons? Get Geo-Matic!
InfosystemsPro LLC
PalmOS apps for engineers and machinists, replacement screws for Tungsten
T, T2, and T3's.
http://www.infosystemspro.com




"jtaylor" wrote in message
. ca...
What is it about copper that makes it so good as a conductor of heat?

Similar q. for silver and electricity.

In article , Robert Swinney says...

Chemistry and valence electrons. Gold also. Do a google for "conductors".

I think he was asking why thermal and electrical conductivity
tend to go hand-in-hand.

The answer is that head is carried by two mechanisms in materials,
by phonons and by conduction electrons. Things that have highly
mobil conduction electrons also conduct heat very well.

Alloys have built-in impurity sites so both the conduction electrons
and the phonons get scattered.

There are some interesting materials like sapphire (see another
thread here) that exhibit no electrical conductivity, but
very, very large thermal conductivity. At some temperatures it approaches
that of copper.

Now someobody has to explain whey copper is red and gold is, well,
gold-colored.

Jim


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And, while we're at it, if you pound gold thin enough so that you can see
through it, it's blue...

Jerry

"jim rozen" wrote in message
...
In article , Robert Swinney says...

Chemistry and valence electrons. Gold also. Do a google for
"conductors".

I think he was asking why thermal and electrical conductivity
tend to go hand-in-hand.

The answer is that head is carried by two mechanisms in materials,
by phonons and by conduction electrons. Things that have highly
mobil conduction electrons also conduct heat very well.

Alloys have built-in impurity sites so both the conduction electrons
and the phonons get scattered.

There are some interesting materials like sapphire (see another
thread here) that exhibit no electrical conductivity, but
very, very large thermal conductivity. At some temperatures it approaches
that of copper.

Now someobody has to explain whey copper is red and gold is, well,
gold-colored.

Jim


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==================================================

Copper, Silver and Gold are in the same column of the chemical element chart. (same free electron count)

In general Hyper physics states :

The general properties of metals include malleability and ductility
and most are strong and durable. They are good conductors of heat
and electricity. Their strength indicates that the atoms are difficult
to separate, but malleability and ductility suggest that the atoms are
relatively easy to move in various directions. The electrical
conductivity suggests that it is easy to move electrons in any
direction in these materials. The thermal conductivity also involves
the motion of electrons. All of these properties suggest the nature
of the metallic bonds between atoms.


Remember - the larger the atom - the further away the outer shell is from the center.
They are in weak control and are available to move or swap.
They can easily move up/down shells and on/off from atom to atom.

Martin


Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder



jtaylor wrote:
What is it about copper that makes it so good as a conductor of heat?

Similar q. for silver and electricity.



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Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder



jim rozen wrote:
In article , Robert Swinney says...

Chemistry and valence electrons. Gold also. Do a google for "conductors".


I think he was asking why thermal and electrical conductivity
tend to go hand-in-hand.

The answer is that head is carried by two mechanisms in materials,
by phonons and by conduction electrons. Things that have highly
mobil conduction electrons also conduct heat very well.

Alloys have built-in impurity sites so both the conduction electrons
and the phonons get scattered.

There are some interesting materials like sapphire (see another
thread here) that exhibit no electrical conductivity, but
very, very large thermal conductivity. At some temperatures it approaches
that of copper.

Now someobody has to explain whey copper is red and gold is, well,
gold-colored.

Jim


Reflection and absorption.
Martin

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Atomic Physics.
What wavelength will pass through - and what will be absorbed.
Short UV and blue can pass. Sneaking through the pickets of electrons
while the Red is absorbed as energy.

Martin

Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder



Jerry Foster wrote:
And, while we're at it, if you pound gold thin enough so that you can see
through it, it's blue...

Jerry

"jim rozen" wrote in message
...

In article , Robert Swinney says...

Chemistry and valence electrons. Gold also. Do a google for

"conductors".

I think he was asking why thermal and electrical conductivity
tend to go hand-in-hand.

The answer is that head is carried by two mechanisms in materials,
by phonons and by conduction electrons. Things that have highly
mobil conduction electrons also conduct heat very well.

Alloys have built-in impurity sites so both the conduction electrons
and the phonons get scattered.

There are some interesting materials like sapphire (see another
thread here) that exhibit no electrical conductivity, but
very, very large thermal conductivity. At some temperatures it approaches
that of copper.

Now someobody has to explain whey copper is red and gold is, well,
gold-colored.

Jim


--
================================================ ==
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
================================================ ==




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"Jerry Foster" wrote in message
t...
And, while we're at it, if you pound gold thin enough so that you can see
through it, it's blue...

Jerry

Purple, actually. Colloidal gold.

Harold

In article , Martin H. Eastburn
says...

Now someobody has to explain whey copper is red and gold is, well,
gold-colored.

Reflection and absorption.
Martin

Ah but aluminum reflects and absorbs light too - it does so
evenly across the spectrum. What's so special about, say,
copper, that causes it to reflect more of the red. Something
special is going on there.

Jim


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"jim rozen" wrote in message
...
Now someobody has to explain whey copper is red and gold is, well,
gold-colored.

Reflection and absorption.

Ah but aluminum reflects and absorbs light too - it does so
evenly across the spectrum. What's so special about, say,
copper, that causes it to reflect more of the red. Something
special is going on there.

Yep. Has something to do with the plasma frequency...
http://www.du.edu/~jcalvert/phys/physhom.htm
Copper/silver/gold page, and particle physics if you dare.

Tim

--
Deep Fryer: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

In article , Tim Williams says...

Yep. Has something to do with the plasma frequency...

"Why is a penny red?"

That child's question could not really be answered
until a very few years ago.

Ignoring the fact that pennies aren't much copper anymore....

Jim


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==================================================

First of all let us not think that everything that reflects has 100% of the
color and image that came into it to be reflected.
You seem to think this way.

All elements have distinctive burn colors and absorbs and reflects based
on the atomic model.

Chrome is blue when done over steel - it is not all that cool looking.
When copper is plated on the steel and then the copper is chromed the color is shifted to the white.

This is a very complex line of work. Paints, inks and glass all requires real knowledge.
Ever have yellow shooting glasses ? See yellow and high contrast. Knocks out the UV that
is fuzzy.

I don't think Al reflects and absorbs evenly across the spectrum - that would be really ODD.

Martin
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder



jim rozen wrote:
In article , Martin H. Eastburn
says...


Now someobody has to explain whey copper is red and gold is, well,
gold-colored.


Reflection and absorption.
Martin


Ah but aluminum reflects and absorbs light too - it does so
evenly across the spectrum. What's so special about, say,
copper, that causes it to reflect more of the red. Something
special is going on there.

Jim



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In article , Martin H. Eastburn
says...

First of all let us not think that everything that reflects has 100% of the
color and image that came into it to be reflected.
You seem to think this way.

All elements have distinctive burn colors and absorbs and reflects based
on the atomic model.

Atomic absorption and emission (from flame spectra, like you are
discussing now) are very different than the optical effects from
metals reflecting incident light. Flame spectroscopy like that
can be done on non-metals.

I don't think Al reflects and absorbs evenly across the spectrum - that would be
really ODD.

Actually it pretty much does. If you were to look at a reflection
spectrum from a metal like aluminum, where the fermi level is such that
there are plenty of electrons to respond to the incident wave, you
find that there's a pretty flat response in the visible. It does
fall off in the UV and the IR.

Jim


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==================================================

Jim -

Can you tell me the number of that perfect Al ?

2xxx contains copper
2xxx contains copper and Mg
6xxx contains mg and Si
7xxx contains Zn and Mg
7xxx contains Zn, Mg, Cu
5xxx contains Mg
3xxx contains Mn
4XXX contains Si
1xxx is ?pure more or less ?

I think you generalized to make your point.

Martin

Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder



jim rozen wrote:
In article , Martin H. Eastburn
says...


First of all let us not think that everything that reflects has 100% of the
color and image that came into it to be reflected.
You seem to think this way.

All elements have distinctive burn colors and absorbs and reflects based
on the atomic model.


Atomic absorption and emission (from flame spectra, like you are
discussing now) are very different than the optical effects from
metals reflecting incident light. Flame spectroscopy like that
can be done on non-metals.


I don't think Al reflects and absorbs evenly across the spectrum - that would be
really ODD.


Actually it pretty much does. If you were to look at a reflection
spectrum from a metal like aluminum, where the fermi level is such that
there are plenty of electrons to respond to the incident wave, you
find that there's a pretty flat response in the visible. It does
fall off in the UV and the IR.

Jim



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In article , Martin H. Eastburn
says...

Jim -

Can you tell me the number of that perfect Al ?

2xxx contains copper
2xxx contains copper and Mg
6xxx contains mg and Si
7xxx contains Zn and Mg
7xxx contains Zn, Mg, Cu
5xxx contains Mg
3xxx contains Mn
4XXX contains Si
1xxx is ?pure more or less ?

Most mirrors are made with *pure* aluminum, there is no
alloying agent used. The stuff on my shelf is 5/9s IIRC.

Jim


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==================================================

I agree mirrors are sputtered Aluminum or sheet silver or my gaudy sheet gold :-)
The glass is typically, not always by any means a safety glass with an index of refraction
and absorbs producing defects.

In camera lenses they use rare earth glass to limit distortion. I don't think
any of us could afford a half-length hallway mirror in rare earth materials.

To the eye it is close enough or fine enough to use. Some are better.
Martin
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder



jim rozen wrote:
In article , Martin H. Eastburn
says...

Jim -

Can you tell me the number of that perfect Al ?

2xxx contains copper
2xxx contains copper and Mg
6xxx contains mg and Si
7xxx contains Zn and Mg
7xxx contains Zn, Mg, Cu
5xxx contains Mg
3xxx contains Mn
4XXX contains Si
1xxx is ?pure more or less ?


Most mirrors are made with *pure* aluminum, there is no
alloying agent used. The stuff on my shelf is 5/9s IIRC.

Jim



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In article , Martin H. Eastburn
says...

I agree mirrors are sputtered Aluminum or sheet silver or my gaudy sheet gold
:-)
The glass is typically, not always by any means a safety glass with an index of
refraction
and absorbs producing defects.


The best mirrors are so-called "first surface" mirrors, where there is
no glass between the incoming and outgoing waves. The metal is on
the *front* of the glass.

A close inspection of the average bathroom mirror shows *two* images - one
from the indident wave being reflected off the interface between the
glass and the air, and the stronger one from the metal to the glass interface.
Very annoying.

After accidentally smashing my truck side-view mirror, I found that it
was indeed first surface - and the one the glass folks tried to install
was not. The replacment performed poorly.

Jim


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==================================================

"jim rozen" wrote in message
...
In article , Martin H. Eastburn
says...

I agree mirrors are sputtered Aluminum or sheet silver or my gaudy sheet
gold
:-)
The glass is typically, not always by any means a safety glass with an
index of
refraction
and absorbs producing defects.


The best mirrors are so-called "first surface" mirrors, where there is
no glass between the incoming and outgoing waves. The metal is on
the *front* of the glass.

A close inspection of the average bathroom mirror shows *two* images - one
from the indident wave being reflected off the interface between the
glass and the air, and the stronger one from the metal to the glass
interface.
Very annoying.

After accidentally smashing my truck side-view mirror, I found that it
was indeed first surface - and the one the glass folks tried to install
was not. The replacment performed poorly.

Jim

really? front surface mirror scratches REALLY easily. even handling it
gently when i make kalidiscopes and attempting to clean it leaves scratches.
was there any protection on the front of it to protect the metal surface?

regards,
charlie
http://glassartists.org/chaniarts

In article , Charles Spitzer says...

After accidentally smashing my truck side-view mirror, I found that it
was indeed first surface - and the one the glass folks tried to install
was not. The replacment performed poorly.

really? front surface mirror scratches REALLY easily. even handling it
gently when i make kalidiscopes and attempting to clean it leaves scratches.
was there any protection on the front of it to protect the metal surface?

Nope, just an aluminized first surface mirror. No coatings, nothing
fancy. It held up pretty well - until that lady in the jaguar crossed
over the line one day, and our mirrors collided. I think she wound
up paying more for hers, than I did for mine.

:^)

Jim


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Yes the first or front face mirror is available but expensive. It also isn't
truly front - as a protective layer of something is used to keep the airborne chlorine
and salts from eating up the Al.

Telescope mirrors are front face - have to be - and are replaced periodically due to the
chloride issue. That is when the comet catcher sees a field of stuff that doesn't move :-)


Martin

Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder



jim rozen wrote:
In article , Martin H. Eastburn
says...

I agree mirrors are sputtered Aluminum or sheet silver or my gaudy sheet gold
:-)
The glass is typically, not always by any means a safety glass with an index of
refraction
and absorbs producing defects.



The best mirrors are so-called "first surface" mirrors, where there is
no glass between the incoming and outgoing waves. The metal is on
the *front* of the glass.

A close inspection of the average bathroom mirror shows *two* images - one
from the indident wave being reflected off the interface between the
glass and the air, and the stronger one from the metal to the glass interface.
Very annoying.

After accidentally smashing my truck side-view mirror, I found that it
was indeed first surface - and the one the glass folks tried to install
was not. The replacment performed poorly.

Jim



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