What differentiates an isolated system from a closed system?

An isolated system is defined by its inability to exchange both matter and energy with its surroundings. This means that within an isolated system, the total energy and total mass remain constant, as no interactions occur with the external environment. This characteristic distinguishes isolated systems from other types of thermodynamic systems, particularly closed and open systems.

In contrast, closed systems can exchange energy with their surroundings but do not allow the transfer of matter. Therefore, the defining feature of an isolated system, as described in the answer, is its complete lack of exchange of both energy and matter, which is pivotal when studying thermodynamic processes and conservation laws.

In essence, the nature of isolated systems leads to many implications in thermodynamics, such as the inability to do work on or receive energy from the environment, making them perfect models for certain theoretical analyses. Understanding this concept is vital for grasping more complex thermodynamic behaviors in real-world applications.