We explain what the difference is between an open, closed and isolated system, the relationship of each one with the environment and its characteristics.
What is the difference between an open, closed and isolated system?
To understand the difference between a open system, a system closed and a isolated system, we must first understand what we mean by "system”. As the dictionary defines it, a system is a set of interrelated and ordered things that contribute to an end.
That is to say, that a system is an organized whole, a notion that applies both to certain sets of body organs, or to the totality of a natural ecosystem, as well as to different phenomena and air temperatures in the atmosphere. Any segment of the universe that we decide to study in itself, ignoring the rest and focusing on its internal relationships, is a system.
This notion is extremely useful in physics, since through a glance systemic we can identify the energetic and material phenomena that occur around us.
Thus, it is common to speak of physical systems, such as systems thermodynamic, in which there is a flow of matter Y Energy internal, which can be more or less linked to the environment. That is, a system can be more open or more closed, depending on how much information get in and out of it. The information that circulates can be for example matter and / or energy.
Thus, we have three main types of physical systems: open, closed, and isolated.
- Open systems. They are those who freely exchange matter and energy with the outside. For example, our bodies themselves are systems in continuous exchange with the environment: oxygen and food enter them, and waste substances are expelled, such as CO2 or ammonia in urine. In addition, we continuously lose heat when the environment is colder, and we lose humidity (water steam) with every breath we take.
- Closed systems. They are those that freely exchange energy (but not matter) with their environment. This energy can be in the form of heat, light or job. For example, a light bulb is a closed system in which not a single particle of matter enters or leaves, but it enters electricity and it is extracted light energy In return.
- Isolated systems. They are those that do not exchange matter or energy with the environment, either because they are very far from any other system or because they have barriers that reduce (or, ideally, prevent) the transit between the inside and the outside. For example, a thermos for hot water is designed to delay as much as possible (prevent it altogether is impossible) the cooling of the liquids inside, thus minimizing the loss of heat from the substance.
We must insist that in the strict sense there is no totally isolated system in the universe. All systems exchange information to some extent with their environment, although in some cases in negligible amounts or simply in such a way that it can be ignored for the study of the system itself.