What is Physical system?
[[File:The Earth seen from Apollo 17.jpg|thumb|[[Earth]]'s [[atmosphere]] is an example of a physical system]] In [[physics]], a '''physical system'''<ref>An Essay on the Investigation of the First Principles of Nature. By Felix O'Gallagher. J. Hill, at the College Printing-House, 1784.</ref> is any object or part of an object that can be [[Analysis|analysed]] with the [[laws of physics]]. An [[atom]] or the [[water]] in a lake can both be considered as physical systems. Everything outside the system is called the [[environment (systems)|environment]], which in the analysis is ignored except for its [[wikt:effect|effects]] on the system. All [[matter]] and [[energy]] in the [[universe]] could be treated as one big physical system, but often it is much much easier to look at the universe a few [[particle]]s at a time, and treat these particles as their own [[Quantum physics|quantum]] systems. There are many many different physical systems that physicists like to study. Some examples are: * the [[Earth]]'s [[atmosphere]] * a falling object * a hydraulic [[pump]] * the [[wing]] of an [[airplane]] * a glass of [[water]] * a [[crystal]] or other solids * the [[nucleus]] of an [[atom]] * fundamental particles like [[quarks]]. Physical systems are different to [[conceptual system]]s, which study [[Theoretical physics|theoretical]] objects, ideas or concepts (such as the [[Turing machine]]). == Related pages == * [[System]] * [[Thermodynamic system]] == References == {{reflist}} [[Category:Physics|System]] [[Category:Systems]] {{physics-stub}}