Transformation of energy

Isolated System in Thermodynamics: Definition and Examples

Isolated system in thermodynamics: definition and examples

An isolated system is a thermodynamic system that does not exchange energy or matter with its surroundings (quite the opposite of an open system). In other words, it is a completely closed system that does not allow any heat, work, or mass transfer through its boundaries even though it is not in thermodynamic equilibrium.

This type of system is an idealized concept and can be challenging to find in practice. However, it is helpful because it allows one to study how a system's energy changes without considering the environmental effects.

What Is the Difference Between Open, Closed, and Isolated Systems?

An open system can exchange both matter and energy with its surroundings. In other words, an open system allows the transfer of matter and energy across its boundaries.

A closed system can exchange energy but not matter with its surroundings. This means that the total amount of matter in the system remains constant, but energy can be exchanged between the system and its surroundings.

Finally, an isolated system is a system that does not allow the exchange of either matter or energy with its surroundings. This means that the system's total amount of matter and energy remains constant.

What Is an Isolated System For?

Isolated systems are used in thermodynamics as theoretical tools to study how the energy of a system changes without taking into account the effects of the environment. This is especially useful for studying the internal energy of a system since it allows us to ignore the transfers of heat or work that can occur with the environment.

Isolated systems are also used in physics and engineering to design and evaluate systems that must maintain a certain amount of internal energy, such as vacuum chambers, cryogenic systems, and nuclear reactors.

In addition, isolated systems are also helpful for studying energy behavior in different natural processes, such as the adiabatic expansion of a gas and the cooling of an object due to radiation, among others.

Examples of Isolated Systems

Except for the universe, all isolated systems are ideal systems. However, in many applications, the exchange of matter and energy can be considered zero in order to simplify the calculations. Some examples of isolated systems are:

  • A fully sealed thermos flask containing a hot beverage: The system is completely closed and does not allow entering or exiting heat or matter into the surroundings.

  • The universe is an example of an isolated system in that it does not exchange energy or matter with anything outside it. This example is the only one that is a truly isolated system.

  • A wetsuit is an example of how a thermal insulator can be used to keep an insulated system without any transfer of energy, in this case, the human body, at a constant temperature, which is helpful for cold water sports.

  • An isolated solar system is a theoretical model in which the solar system is considered an isolated system in which mass or energy can not enter or leave other systems outside of it. It is assumed that it does not allow any type of exchange (neither matter nor energy) with the rest of the universe without considering the effects of other celestial bodies or external forces, such as the gravitational influence of other stars or galaxies.


Published: April 12, 2023
Last review: April 12, 2023