What does an open system allow for?

An open system is defined by its ability to exchange both matter and energy with its surroundings. This characteristic allows for interactions with the environment, meaning that substances can flow into the system or out of it. For instance, consider a cup of hot coffee left on a table: it can lose heat to the surrounding air and also allows for vapors (water molecules) to escape into the atmosphere. This flexibility distinguishes open systems from closed or isolated systems, which do not permit such exchanges. The key aspect of an open system is its dynamic nature, where various processes like chemical reactions, mass transfer, and energy flow can occur, significantly influencing the system's overall behavior and properties.