In
science and
engineering, a
system is the part of the
universe that is being studied, while the
environment is the remainder of the universe that lies outside the boundaries of the system. It is also known as the
surroundings, and in
thermodynamics, as the
reservoir. Depending on the type of system, it may interact with the environment by exchanging
mass,
energy (including
heat and
work),
linear momentum,
angular momentum,
electric charge, or
other conserved properties. In some disciplines, such as
information theory,
information may also be exchanged. The environment is ignored in analysis of the system, except in regard to these interactions.