Closed (and isolated) system definition

A closed or isolated system is a type of system that, due to its characteristics, does not exchange any type of information, energy or matter with its environment or surroundings. In any case, according to some bibliography, there are distinctions between what is a closed system and an isolated system that will be explained later.

Systems, depending on whether or not they exchange with their environment, can be classified as: open or closed. And, as stated, some bibliographies include the isolates (completely closed).

In practice there is no completely open or completely closed (isolated) system; there are different degrees of openness of a system.

Probably the only case of a completely closed system (or isolated system) is the Universe itself, at least as far as current physical theory recognizes.

However, for study purposes, many systems that are not completely closed can be studied as such to a very good or almost perfect degree of approximation. In these cases, the closed system is considered as such only when they do not exchange matter with their environment, but it is accepted that they exchange energy.

There are systems that are preferably more closed, such as a thermos that keeps hot water, the more it is isolated from the environment, the longer it conserves the caloric energy inside. Inevitably, over time, the water inside it takes on room temperature because the system is not perfectly closed (it is not an isolated system).

An important property of closed systems is that the time evolution equations, called equations of motion of said system, depend exclusively on variables and factors contained in it. In other words, the variables of its environment do not alter the closed system at all.

Difference between isolated, closed and open system. License

Isolated system vs closed system

In physical science, an isolated system is any of the following:

– A physical system so far removed from other systems that it does not interact with them.
– A thermodynamic system closed by rigid and immobile walls through which neither mass nor energy can pass.

Although internally subject to its own gravity, an isolated system is usually considered to be beyond the reach of external gravitational and other long-range forces.

This can be contrasted with what (in the terminology more commonly used in thermodynamics) is called a closed system, enclosed by selective walls through which energy can pass as heat or work, but not as mass of substance; and with an open system, in which both mass and energy can enter or leave, although it may have impermeable walls at parts of its boundaries.

Closed systems in different disciplines

A closed system is a physical system that does not allow certain types of transfers (such as mass and energy transfer) into or out of the system. Specifying which types of transfers are excluded varies in closed physical, chemical, or engineering systems.

Closed systems in classical mechanics

In classical nonrelativistic mechanics, a closed system is a physical system that does not exchange matter with its surroundings, and is not subject to any net force whose source is external to the system. A closed system in classical mechanics would be considered an isolated system in thermodynamics. Closed systems are often used to limit the factors that can affect the results of a specific problem or experiment.

closed systems in thermodynamics

– Closed system versus isolated system: In thermodynamics, a closed system can exchange energy (such as heat or work) but not matter, with its surroundings. An isolated system cannot exchange heat, work, or matter with its surroundings, whereas an open system can exchange energy and matter. (This scheme of definition of terms is not generally accepted in all bibliographies.)

closed systems in chemistry

In chemistry, a closed system is one through which no reactants or products can escape, only heat can be freely exchanged (for example, an ice refrigerator). A closed system can be used when conducting chemical experiments in which temperature is not a factor (that is, when thermal equilibrium is reached).

Closed systems in engineering

In an engineering context, a closed system is a bounded, i.e. defined, system in which every input is known and every result is known (or can be known) within a specified time.

related terminology

System
Open system
limit of a system

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