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
Irreversibility refers to a process or change that cannot be undone or reversed. It is a fundamental concept in physics and thermodynamics, and describes the concept that certain processes or systems cannot return to their original state.
Irreversibility is caused by the increase in entropy, or disorder, of a system. This can be due to factors such as friction, heat transfer, and the second law of thermodynamics, which states that the total entropy of a closed system will always increase over time.
Understanding irreversibility is crucial in many scientific fields, including physics, chemistry, and biology. It helps us predict and explain the behavior of systems and processes, and is essential for technological advancements such as energy production and efficiency.
In most cases, irreversibility cannot be completely avoided. However, it can be minimized through careful design and control of processes and systems. For example, in thermodynamics, reversible processes are designed to minimize the increase in entropy and maximize efficiency.
Some common examples of irreversibility include the burning of fuel, the melting of ice, and the mixing of two substances. These processes cannot be reversed, and the original state of the system cannot be restored. Another example is the aging process, which is irreversible due to the increase in entropy of biological systems over time.