# Clock and entropy

Hi All

Does anybody know if there is a clock whose mechanism is based on the increase of the entropy of a given system ?

Would it be possible or easy to build ?

Best wishes

DaTario

I mean, sure, you could base a clock on a carnot cycle or some other type of cycle pretty easily. You could also base a clock off of how long it takes two bodies to come to equilibrium. I don't, myself, know of any examples though. Are you thinking of any specific entropy increase processes?

Danger
Gold Member
The question somewhat confuses me. As far as I know, they all work that way.

The question somewhat confuses me. As far as I know, they all work that way.

Ok I guess I understand your point. What I mean is: Is it in principle possible to build a clock whose inner mechanism depends only on monitoring the increase of entropy and, based on its increase rate, the time is counted ?

Best wishes

DaTario

Dale
Mentor
2020 Award
Sure, you could make something that burns at a specific rate, like a fuse.

Danger
Gold Member
Is it in principle possible to build a clock whose inner mechanism depends only on monitoring the increase of entropy and, based on its increase rate, the time is counted ?

Dale has a good idea, but such a thing would be extremely short-lived. The only long-term mechanism that I can immediately think of is one based upon radioactive decay of a calibrated source substance.

DaTario,

You probably own one or more entropy-controlled clock.
Just look at your wrist !

A mechanical wrist watch is the best example of an entropy-controlled clock.
Feynam explained clearly why the dissipation of mechanical energy (into heat) is a absolute prerequisite for the proper functioning of a simple wrist watch. The ratchet wheel controls the time regularity of your mechanical wrist watch, one entropy tick at a time! Without dissipation of mechanical energy into work, the ratchet would simply not work!

If you own and electronic wrist watch, it is not so much different as you simply need to consider the equivalent electronic ratchet gate. Tell me more about that if you are an electronic expert.

I like very much to answer YES to this question, but I am not sure, of course.
And similarly, I would answer YES for any clock built on any kind of technology.

This brings us to the even bigger question of the different arrows of time.
Have fun with "The Physical Basis of The Direction of Time" by Zeh, if you want to know more about it.
In this book you will read about different arrows of time and how they are related.

I have not yet finished reading this book.
However, I think there is really room to accept that all directions of time share the same ultimate cause.
Therefore, I would answer your question by saying that probably all clocks are entropy-controlled, entropy being a generic name for the same ultimate arrow of time.

Have fun, and fun.

Michel

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DaTario,

You probably own one or more entropy-controlled clock.
Just look at your wrist !

A mechanical wrist watch is the best example of an entropy-controlled clock.
Feynam explained clearly why the dissipation of mechanical energy (into heat) is a absolute prerequisite for the proper functioning of a simple wrist watch. The ratchet wheel controls the time regularity of your mechanical wrist watch, one entropy tick at a time! Without dissipation of mechanical energy into work, the ratchet would simply not work!

If you own and electronic wrist watch, it is not so much different as you simply need to consider the equivalent electronic ratchet gate. Tell me more about that if you are an electronic expert.

I like very much to answer YES to this question, but I am not sure, of course.
And similarly, I would answer YES for any clock built on any kind of technology.

This brings us to the even bigger question of the different arrows of time.
Have fun with "The Physical Basis of The Direction of Time" by Zeh, if you want to know more about it.
In this book you will read about different arrows of time and how they are related.

I have not yet finished reading this book.
However, I think there is really room to accept that all directions of time share the same ultimate cause.
Therefore, I would answer your question by saying that probably all clocks are entropy-controlled, entropy being a generic name for the same ultimate arrow of time.

Have fun, and fun.

Michel

Thank you all for the answers.

By using only reversible processes, by maintaining the entropy stationary, one can build a machine that measures time?

Perhaps the possible redundancy may help me to understand better this concepts.
Best wishes

DaTario

Hmm - how about a massive iron ball spinning in empty space? Like the earth for example, sort of. That would be the first clock ever invented. But then, to read the time, you would need something like a star (or a sun) to measure the amount of rotation, and that means light, and that means entropy increase. But this is close to a reversible process, and the closer you get to a reversible process, the less the clock would run down. "Reversible" is an ideal that can only be approximated, never achieved.

My intuition guides me to think that for time measurement, entropy needs to increase, at least in the system containing the clock, the mearuring apparatus ane the observer.

Perhaps I am proposing something like decoherence stuff in quantum measurement and complementary principle.

Best wishes

DaTario