Will Our Buildings Eventually Collapse Due to Entropy?

[look416]

After reading the 2nd law of thermodynamics and entropy, it let's me think about our building. since entropy tends to maximize as time flows, doesn't that our building will slowly tends to collapse as our building has such low entropy at first? how can we measure such rate? or does can the building collapse in just 70 or 80 years ?

 

[revelation101]

second law states that a process occurs towards the direction where its entropy increases.it is when you start the process.in the case of building you stated here,it is stable.if you try to unstabilize it ,it will result in the destruction of the building,thus increasing its disorderness or simply,entropy.you cannot bring back the same building to original state by giving the same unstabilizing process.spotaneous process only occurs in the direction ,where its entropy increases.

 

[look416]

ok, what your view stated is right, but how about the process of wind blowing on the building, all the skyscraper will have to withstand the strong current of the wind, but during that process, doesn't that the wind will blow away some of the molecules of the building hence causing it to undergo entropy? since entropy states that when you start the process of the unstablizing , it will only end when the entropy is maximized, doesn't that mean sooner or later the builiding will crumble into a pile without any external process?

 

[Andy Resnick]

After reading the 2nd law of thermodynamics and entropy, it let's me think about our building. since entropy tends to maximize as time flows, doesn't that our building will slowly tends to collapse as our building has such low entropy at first? how can we measure such rate? or does can the building collapse in just 70 or 80 years ?

You are absolutely correct- without free energy input buildings crumble, mountains erode, and living things die.

Measuring the rate of entropy increase for these processes is difficult- I am unaware of any serious attempt to do so.

 

[A. Neumaier]

ok, what your view stated is right, but how about the process of wind blowing on the building, all the skyscraper will have to withstand the strong current of the wind, but during that process, doesn't that the wind will blow away some of the molecules of the building hence causing it to undergo entropy? since entropy states that when you start the process of the unstablizing , it will only end when the entropy is maximized, doesn't that mean sooner or later the building will crumble into a pile without any external process?

The entropy in the second law is a measure of microscopic complexity, not of the complexity of macroscopic arrangements. The entropy of a building is essentially the sum of the entropies of its pieces, no matter how complex they are arranged.

Thermodynamics governs what happens in small pieces of matter - from which the laws of elasticity, chemical flow and hydromechanics governing wind, building statics and corrosion. There entropy is just a field, describing the local entropy density at each point.

 

[Andy Resnick]

The entropy in the second law is a measure of microscopic complexity, not of the complexity of macroscopic arrangements. The entropy of a building is essentially the sum of the entropies of its pieces, no matter how complex they are arranged.

Thermodynamics governs what happens in small pieces of matter - from which the laws of elasticity, chemical flow and hydromechanics governing wind, building statics and corrosion. There entropy is just a field, describing the local entropy density at each point.

The second law is a universal statement- it is not restricted to "microscopic complexity", nor is it only considered as belonging to subassemblies of a larger system. It's not clear if one can assign an arbitrary entropy to a system since there is an unambiguous temperature scale- the entropy field is not independent of the other components of the general energy balance equation.

I should have expounded to the OP- changes to the entropy only tell you if a process is reversible or not; changes to the *free energy* tell you if a process is spontaneous or not. A given process may be spontaneous and irreversible (rusting), non-spontaneous and reversible (an isothermal chemical reaction requiring an activation energy), etc. etc. Thus, a building will spontaneously and irreversibly crumble over time (unless regular maintenance is performed).

 

[look416]

Andy, just like the theory of the heat death of the universe, the scientist had even estimated the remaining time of what we have until the death of universe, surely they can estimated the death of the building, maybe building just can last longer then all of us can think of,
what it also makes me think of is whether the architect will take in consider of such laws? maybe they just simply put a period to the building, after some time, they just do the maintainence or just stating the building is too dangerous for human to live in?

Also, I am interested in what you have mentioned before regarding the influence of the entropy to the law of elasticity, could you briefly explain to me how it works?

 

[Andy Resnick]

Andy, just like the theory of the heat death of the universe, the scientist had even estimated the remaining time of what we have until the death of universe, surely they can estimated the death of the building, maybe building just can last longer then all of us can think of,
what it also makes me think of is whether the architect will take in consider of such laws? maybe they just simply put a period to the building, after some time, they just do the maintainence or just stating the building is too dangerous for human to live in?

Time-to-failure curves are a basic part of reliability analysis, which is why we can say things like "LEDs last 100,000 hours":

http://en.wikipedia.org/wiki/Bathtub_curve

Entropy does not play a meaningful part of this type of analysis.

Also, I am interested in what you have mentioned before regarding the influence of the entropy to the law of elasticity, could you briefly explain to me how it works?

I did not say that- I think you are quoting someone else.

 

[look416]

ops sorry, watching wrong posts

so regarding the bathtub curve, are meant to test the reliability of the building in this case, i got it, so they never really account the entropy in when they building it, but using the time to failure curves as a reference thanks andy.

just help me close the thread pls, since i think the question is solved.

 

[revelation101]

You are absolutely correct- without free energy input buildings crumble, mountains erode, and living things die.

Measuring the rate of entropy increase for these processes is difficult- I am unaware of any serious attempt to do so.

a small question,if i take a cube of any material,remove some of its molecules somehow,and keep it in vacuum under zero gravity,will the cube crumble into a pile after some years?does that mean work is done without input of energy?

 

[Andy Resnick]

a small question,if i take a cube of any material,remove some of its molecules somehow,and keep it in vacuum under zero gravity,will the cube crumble into a pile after some years?does that mean work is done without input of energy?

It depends on the material- many compounds are metastable. My stock of Fura-2 AM, for example, is only good for a few months (dry powder) or a few weeks (dissolved in water). I can't speak to the ultimate stability of matter- a cube of iron, for example- but there's no reason to assume the cube will remain 'as is' in perpetuity.

 

[A. Neumaier]

The second law is a universal statement- it is not restricted to "microscopic complexity", nor is it only considered as belonging to subassemblies of a larger system.

Yes, and it says the the entropy balance in a hydrodynamic description of a macroscopic system is never on the negative side - nothing more. All that is determined by what happens very locally, in the small mesoscopic pieces of matter in local equilibrium of which a macroscopic body is build. In particular, it doesn't say anything about the complexity of the features in the macroscopic field.