The Naked Scientists
Toggle navigation
Login
Register
Podcasts
The Naked Scientists
eLife
Naked Genetics
Naked Astronomy
In short
Naked Neuroscience
Ask! The Naked Scientists
Question of the Week
Archive
Video
SUBSCRIBE to our Podcasts
Articles
Science News
Features
Interviews
Answers to Science Questions
Get Naked
Donate
Do an Experiment
Science Forum
Ask a Question
About
Meet the team
Our Sponsors
Site Map
Contact us
User menu
Login
Register
Search
Home
Help
Search
Tags
Recent Topics
Login
Register
Naked Science Forum
Non Life Sciences
Physics, Astronomy & Cosmology
Would compressed air generate the same heat in 1000 years as 1 day?
« previous
next »
Print
Pages: [
1
]
Go Down
Would compressed air generate the same heat in 1000 years as 1 day?
2 Replies
3778 Views
0 Tags
0 Members and 1 Guest are viewing this topic.
jammie001
(OP)
First timers
3
Activity:
0%
Would compressed air generate the same heat in 1000 years as 1 day?
«
on:
21/09/2011 18:44:36 »
Lets say we have a volume of air and compress it a certain amount in 1 day and it generates heat. Would this same
volume of air generate the same amount of heat if compressed by the same amount but over the course of 1000 years?
Logged
chris
Naked Science Forum King!
8061
Activity:
1.5%
Thanked: 306 times
The Naked Scientist
Would compressed air generate the same heat in 1000 years as 1 day?
«
Reply #1 on:
21/09/2011 19:40:22 »
Yes; the work done in compressing the molecules would be identical and hence, assuming no losses, the resulting temperature change would be the same, albeit over a much longer time scale.
Logged
I never forget a face, but in your case I'll make an exception - Groucho Marx -
https://www.thenakedscientists.com/
Soul Surfer
Naked Science Forum King!
3389
Activity:
0%
Thanked: 8 times
keep banging the rocks together
Would compressed air generate the same heat in 1000 years as 1 day?
«
Reply #2 on:
21/09/2011 20:23:30 »
Both compressions suggested are relatively slow and the heat would escape but the rate of generation of heat would be slower the slower the compression. It gets more interesting if the compression is done quickly say in a tenth of a second or less.
If the gas was totally isolated and no heat was allowed to escape it would be true but to compress any gas it is necessary to have it in a containing vessel and with a slow compression the heat generated would be lost to the walls of the vessel. Let us assume that this has a large thermal capacity and stays at the same temperature as the gas is slowly compressed. You would find that the effort expended to reduce the gas to say half its original volume was less than the effort needed to do it quickly.
This is also easy to understand if you think about what would happen with the quick compression reducing the volume to half. the gas would heat up and the pressure would obviously be higher than if I held the volume the same and allowed it to cool back down to the starting temperature.
Note the quick change is called an adiabatic change (meaning that thermal equilibrium is not maintained) the slow change is called an isothermal change (i.e. thermal equilibrium is maintained)
«
Last Edit: 21/09/2011 20:29:01 by Soul Surfer
»
Logged
Learn, create, test and tell
evolution rules in all things
God says so!
Print
Pages: [
1
]
Go Up
« previous
next »
Tags:
There was an error while thanking
Thanking...