The discussion centers on the concept of irreversibility in thermodynamics, specifically whether it encompasses both macroscopic and microscopic views of processes such as the expansion of an ideal gas and the melting of ice. Participants explore the definitions and implications of irreversibility from different perspectives within thermodynamics.
Participants express differing views on whether irreversibility is defined solely in macroscopic terms or if it also includes microscopic considerations. The discussion remains unresolved, with multiple competing perspectives presented.
Some limitations include the dependence on definitions of irreversibility and the distinction between macroscopic and microscopic viewpoints, which are not fully explored or agreed upon in the discussion.
erty said:The thermodynamic explanation of irreversibility - does it include the microscopic view of a process, i.e. the expansion of a ideal gas (the random movement of the molecules) or the melting of an ice cube?
Or is it only defined within the macroscopic world?
Irreversibility, of course, is the opposite of reversibility. A reversible process is one that can change direction with an infinitessimal change in conditions. In reality, all processes are somewhat irreversible. An example would be the expansion of a gas caused by applying a pressure to a container wall that was infinitessimally lower than the pressure of the gas. An infinitessimal increase in pressure will reverse the expansion and result in a compression of the gas.erty said:The thermodynamic explanation of irreversibility - does it include the microscopic view of a process, i.e. the expansion of a ideal gas (the random movement of the molecules) or the melting of an ice cube?
Or is it only defined within the macroscopic world?
Andrew Mason said:In thermodynamics, reversibility is definitely a macroscopic concept. It has no meaning at the molecular level. Pressure and temperature are macroscopic concepts that relate to qualities of large numbers of molecules and are not defined at the molecular level.
AM