Open Systems
Open systems are defined as systems that allow the exchange of both energy and matter with their surroundings. They are prevalent in nature and include both biological entities, such as the human body, and mechanical systems, such as cars. The key characteristic of open systems is their ability to take in matter (like food or fuel) and energy, while also releasing waste products back into the environment. This dynamic interaction is governed by the principle of conservation of energy, which states that energy cannot be created or destroyed but can only be transformed.
In many cases, open systems may reach a state of dynamic equilibrium, where processes occur at equal rates in opposite directions, leading to stability despite the ongoing exchanges. Over time, however, all systems tend toward increased entropy or disorder, which can diminish their efficiency. Conversely, closed systems permit energy exchange but restrict matter movement, while isolated systems do not allow any exchange of energy or matter. Understanding these classifications of systems is essential across various fields of study, as they help in analyzing complex interactions within defined boundaries.
Open Systems
FIELDS OF STUDY: Classical Mechanics; Thermodynamics
ABSTRACT: A system is a portion of the universe singled out for study. Anything from a single atom to the entire universe may be viewed as a system. A system may be open, closed, or isolated. An open system allows both matter and energy to pass in and out.
PRINCIPAL TERMS
- closed system: a system that may exchange energy, but not matter, with its surroundings.
- conservation of energy: the principle that energy cannot be created or destroyed, only transformed.
- dynamic equilibrium: the state in which reversible reactions occur at equal rates in opposite directions, balancing each other and resulting in no net change.
- entropy: a measure of a system’s level of disorder, which in physics refers to the potential amount of states the molecules of the system may assume.
- radiant energy: energy consisting of electromagnetic radiation; an important mechanism for the transfer of energy in or out of some systems.
- system boundary: a physical or conceptual delineator between a system and the outside environment.
- system efficiency: the proportion of a system’s input it converts to the intended output.
What Is a System?
A system in physics is a portion of the universe that has been chosen for study. A system consists of components viewed as a whole, and systems may be identified at any scale. An atom is a system, as is the entire universe. Systems are defined so that they single out the group of interactions a scientist is interested in studying.
A system may be open, closed, or isolated depending on how it exchanges energy. Open systems, which allow the transfer of both energy and matter in and out, are most common. Most natural systems and created objects are open systems. A closed system allows energy, but not matter, in or out. Earth is often viewed as a closed system, receiving radiant energy from the sun but neither losing nor gaining any matter (other than negligible amounts from meteorites and spacecraft). Isolated systems do not allow matter or energy in or out. The universe is thought to be an isolated system. Perspectives of the types of systems also vary between fields of study.
Open System Characteristics
An open system is characterized by the ability to transfer energy and matter through the system boundary. The human body is a classic biological open system because of the intake of outside matter (food and water) and its subsequent exit. A mechanical system such as a car, which takes in fuel and gives off exhaust, is also open. In both examples, matter and energy are output back into the environment, obeying the principle of conservation of energy.
Typically, when the scope of study is narrow, a system will be open. If the system is broadened to include elements of the environment, it may become closed. Systems may also experience dynamic equilibrium while remaining open.
All systems, including the universe as a whole, tend toward entropy, or randomness. This causes all systems to wear down over time, diminishing system efficiency.
Bibliography
Henderson, Tom. "Isolated Systems." Physics Classroom. Physics Classroom, 2015. Web. 26 Aug. 2015.
Lee, Esther, Jiaxu Wang, and Jonathan Wang. "Dynamic Equilibrium." UC Davis ChemWiki. Regents of the U of California, 10 June 2014. Web. 26 Aug. 2015.
Miller, James Grier, and Jessie L. Miller. "The Earth as a System." Primer Project. Internatl. Soc. for the Systems Sciences, 10 Nov. 1997. Web. 25 Aug. 2015.
Nave, R. "Conservation Laws." HyperPhysics. Georgia State U, 2012. Web. 26 Aug. 2015.
Sanctuary, Bryan. "Open, Closed, and Isolated Systems in Physical Chemistry." Foundations of Quantum Mechanics and Physical Chemistry. MCH Multimedia, 11 July 2011. Web. 26 Aug. 2015.
"What Is Entropy?" Energy Concepts Primer. New Mexico Solar Energy Assoc., 2011. Web. 26 Aug. 2015.