Author |
Topic: Shrinking While Heated (Physics) (Read 531 times) |
|
Barukh
Uberpuzzler
Gender: 
Posts: 2276
|
 |
Shrinking While Heated (Physics)
« on: Jul 4th, 2005, 9:10am » |
 Quote  Modify
|
Is it possible that a solid substance shrinks when its temperarture rises? Assume there is no change in pressure.
|
|
 IP Logged |
|
|
|
JocK
Uberpuzzler
Gender:
Posts: 877
|
|
Re: Shrinking While Heated (Physics)
« Reply #1 on: Jul 4th, 2005, 10:05am » |
Quote Modify
|
the answer is yes (see e.g. http://physics.ucsc.edu/research/zs.html).
|
|
IP Logged |
solving abstract problems is like sex: it may occasionally have some practical use, but that is not why we do it.
xy - y = x5 - y4 - y3 = 20; x>0, y>0.
|
|
|
baddab457
Junior Member
Gender:
Posts: 51
|
|
Re: Shrinking While Heated (Physics)
« Reply #2 on: Jul 4th, 2005, 5:14pm » |
Quote Modify
|
shrink wrap.. 
|
|
IP Logged |
"Dont Die For Your Country, Make Them SoB's Die For Theres" G Paton
|
|
|
Bob Purcell
Guest
|
 |
Re: Shrinking While Heated (Physics)
« Reply #3 on: Jul 5th, 2005, 7:25pm » |
Quote Modify
 Remove
|
Ice
Rap
|
|
IP Logged |
|
|
|
Noke Lieu
Uberpuzzler
pen... paper... let's go! (and bit of plastic)
Gender:
Posts: 1884
|
|
Re: Shrinking While Heated (Physics)
« Reply #4 on: Jul 5th, 2005, 7:52pm » |
Quote Modify
|
A steak on the barbie. 
But there would be a difference in the turgour pressure of the cells. 
And the pressure from your peers to cook it perfectly, but without being seen to fuss over it 
|
|
IP Logged |
a shade of wit and the art of farce.
|
|
|
JocK
Uberpuzzler
Gender:
Posts: 877
|
|
Re: Shrinking While Heated (Physics)
« Reply #5 on: Jul 6th, 2005, 10:07am » |
Quote Modify
|
on Jul 5th, 2005, 7:25pm, Bob Purcell wrote:
Don't think that is correct. Ice has a positive thermal expansion coefficient.
Now, if you allow for a phase transition (from ice into water) or simply consider liquified ice (water in the temperature interval of 0-4 degC), you will observe negative thermal expansion. The question, however, asks us to restrict ourselves to solids.
|
|
IP Logged |
solving abstract problems is like sex: it may occasionally have some practical use, but that is not why we do it.
xy - y = x5 - y4 - y3 = 20; x>0, y>0.
|
|
|
SWF
Uberpuzzler
Posts: 879
|
|
Re: Shrinking While Heated (Physics)
« Reply #6 on: Jul 6th, 2005, 7:40pm » |
Quote Modify
|
Starting at a low enough temperature silica will shrink when heated. Zirconia shows a sudden volume decrease at an elevated temperature due to a (solid state) phase change, as do other solids. The alloy Invar (64 Fe-36 Ni) has near zero, and possibly slightly negative, thermal expansion over a fairly wide range of temperature. Graphite fibers often have negative thermal expansion along the axis of the fiber.
Related to this topic: one of the Maxwell thermodynamic relations says that derivative of volume with respect to temperature at constant pressure equals the negative of the derivative of entropy with respect to pressure at constant temperature.
|
|
IP Logged |
|
|
|
Barukh
Uberpuzzler
Gender:
Posts: 2276
|
|
Re: Shrinking While Heated (Physics)
« Reply #7 on: Jul 6th, 2005, 11:48pm » |
Quote Modify
|
Wow! So many interesting examples from JocK and SWF!
When asking this question, I was aware just of a single example - a certain crystallographic phase of pure plutonium. Look here for the nice graphs.
SWF, could you please provide references for your examples?
|
|
IP Logged |
|
|
|
|
RIDDLES SITE
WRITE MATH!
Home 
Help 
Search 
Members 
Login 
Register
Reply
Notify of replies
Send Topic
Print