Wiktionary
n. (context physics English) A system that does not interact with its surroundings, that is, its total energy and mass stay constant.
Wikipedia
In physical science, an isolated system is either of the following:
- a physical system so far removed from other systems that it does not interact with them.
- a thermodynamic system enclosed by rigid immovable walls through which neither matter nor energy can pass.
Though subject internally to its own gravity, an isolated system is usually taken to be outside the reach of external gravitational and other long-range forces.
This can be contrasted with what (in the more common terminology used in thermodynamics) is called a closed system, being enclosed by selective walls through which can pass energy as heat or work, but not matter; and with an open system, which both matter and energy can enter or exit, though it may have variously impermeable walls in parts of its boundaries.
An isolated system obeys the conservation law that its total energy–mass stays constant. Most often, in thermodynamics, matter and energy are treated as separately conserved.
Because of the requirement of enclosure, and the near ubiquity of gravity, strictly and ideally isolated systems do not actually occur in experiments or in nature. Though very useful, they are thus hypothetical concepts only.
Classical thermodynamics is usually presented as postulating the existence of isolated systems. It is also usually presented as the fruit of experience. Obviously, no experience has been reported of an ideally isolated system.
It is, however, the fruit of experience that some physical systems, including isolated ones, do seem to reach their own states of internal thermodynamic equilibrium. Classical thermodynamics postulates the existence of systems in their own states of internal thermodynamic equilibrium. This postulate is a very useful idealization.
In the attempt to explain the idea of gradual approach to thermodynamic equilibrium after a thermodynamic operation, with entropy increase according to the second law of thermodynamics, Boltzmann’s H-theorem used equations which assumed a system (for example, a gas) was isolated. That is, all the mechanical degrees of freedom could be specified, treating the enclosing walls simply as mirror boundary conditions. This led to Loschmidt's paradox. If, however, the stochastic behavior of the molecules and thermal radiation in real enclosing walls is considered, then the system is in effect in a heat bath. Then Boltzmann’s assumption of molecular chaos can be justified.
The concept of an isolated system can serve as a useful model approximating many real-world situations. It is an acceptable idealization used in constructing mathematical models of certain natural phenomena; e.g., the planets in the Solar System, and the proton and electron in a hydrogen atom are often treated as isolated systems. But from time to time, a hydrogen atom will interact with electromagnetic radiation and go to an excited state.
Sometimes people speculate about "isolation" for the universe as a whole, but the meaning of such speculation is doubtful.
Usage examples of "isolated system".
It states that the entropy of an isolated system always increases, and that when two systems are joined together, the entropy of the combined system is greater than the sum of the entropies of the individual systems.
While this is an impressive strength for any isolated system—.
Klasse Ephemora was an isolated system on the side of Chiss space opposite the galactic Core.
Anyway, for a test run, I want to mount versions on a fully isolated system and then release the virus.
While this is an impressive strength for any isolated system - indeed, a strength which, following the Thebans reunification with the rest of humanity, will do much to repair the weakness which President Anderson has often decried in our own Navy - it cannot be considered a serious threat to the Peace Fleet.
While this is an impressive strength for any isolated system - indeed, a strength which, following the Thebans' reunification with the rest of humanity, will do much to repair the weakness which President Anderson has often decried in our own Navy - it cannot be considered a serious threat to the Peace Fleet.
It would only get worse: tomorrow afternoon, if her navigation was correct, they would hit the Devils Backbone, the massive hogback ridge that separated their canyon system from the even more remote and isolated system in which Quivira was hidden.
It wouldnt be difficult for anyone to find out that I do my initial development work at home on an isolated system.
And he had always dealt with leaders who more or less agreeda widespread ruling class used to centuries of relative calm, used to dealing with isolated system wars through embargo and police action.
And he had always dealt with leaders who more or less agreed-a widespread ruling class used to centuries of relative calm, used to dealing with isolated system wars through embargo and police action.
The total entropy of any isolated system can never decrease in any change.
The total entropy of the Universe therefore is increasing, tending towards a maximum, corresponding to complete disorder of the particles in it (assuming that it may be regarded as an isolated system.
The human pilot got his damaged engine back on line and increased speed down into the isolated system, fleeing toward the water world.