A closed system does not exchange mass with its surroundings and is only capable of exchanging energy with the surroundings. In comparison, an open system is capable of exchanging both mass and energy with its surroundings. And a system that does not exchange mass or energy with its surroundings is known as an isolated system. Earth can be considered as a closed system, since it only receives sunlight (energy), while the overall mass stays constant, without (almost) any exchange from space. Another example of a closed system is a saucepan or frying pan, on a stove, when its lid is closed. In this configuration the saucepan or frying pan receives heat (energy) from the stove, while no mass enters or leaves the pan, thus making it a closed system. Another similar example is a pressure cooker on a stove, with its lid closed.
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