In thermodynamics, we often separate the universe (that is, everything that exists) into 2 parts: the system, which is the small part we are interested in, and the surroundings which is everything out...In thermodynamics, we often separate the universe (that is, everything that exists) into 2 parts: the system, which is the small part we are interested in, and the surroundings which is everything outside the system. A pan on the stove is an open system because water can evaporate or be poured in, and heat can enter the pan if the stove is turned on, and leave the pan also.
