Final answer:
In an isolated system, observed discrepancies in heat exchange could be due to measurement errors, heat loss through imperfect insulation, or phase changes. Real-world isolated systems are approximations, as complete isolation is theoretical.
Step-by-step explanation:
The principle of conservation of energy dictates that in an isolated system, the total heat energy released by warmer substances is equal to the total heat energy absorbed by cooler substances. If discrepancies are observed in an experimental setup meant to be isolated, potential causes could include measurement errors, heat loss due to imperfect insulation, or unaccounted physical processes like phase changes that absorb or release heat without changing temperature.
Isolated systems are theoretical constructs, as in reality, some energy exchange with the environment can occur, although very slowly. Examples of systems with varying degrees of isolation include an open system like a pot of boiling water, a closed system like a sealed pouch in boiling water, and an insulated thermos, which mimics an isolated system. The first law of thermodynamics confirms that any observed changes within an isolated system reflect internal energy redistributions, as opposed to energy exchanges with the environment.