A system is a space in the surrounding or a quantity of matter of fixed identity, around which a boundary can be established. The boundaries may be fixed or moveable. Work or heat can be transferred across the system boundary. The space outside the system is its surroundings. There are two types of systems - open systems and closed systems. Let us understand this with the help of examples.

Examples,

1. While boiling soup in an open saucepan on a stove, energy and matter are being transferred to the surroundings through steam. The saucepan is an open system because it allows for the transfer of matter and for the transfer of energy. This is an example of an open system.

2. A thermos flask having hot water does not allow transfer of heat or energy to its surroundings. Hence it is a closed system.