In which type of system is energy exchanged but matter is not?

In a closed system, energy can be exchanged with the surroundings, while matter cannot be exchanged. This distinction is crucial in understanding the behavior of different systems in environmental science and ecology.

For instance, consider a sealed container of gas. It can exchange heat with its environment, allowing for energy transfer, such as warming up or cooling down, but the gas itself remains contained within the system. The closed nature of matter flow makes it distinct from an open system, where both energy and matter can be exchanged, and from an isolated system, where neither can be exchanged.

Understanding closed systems is particularly relevant in contexts such as studying energy conservation in ecosystems, where energy inputs and outputs can affect system dynamics without the introduction or removal of new material components. Additionally, closed systems help to model scenarios in environmental management and sustainability, where the focus is on energy flow rather than material flow.