Question

Plants and living beings are examples of: (a) Isolated system (b) Adiabatic system (c) Open system (d) Closed system

Short answer

Plants and living beings are examples of an open system (c).

Step-by-step solution

Understanding System Types

First, let's define each type of system. An isolated system does not exchange matter or energy with its surroundings. An adiabatic system does not exchange heat with its surroundings. An open system exchanges both matter and energy with its surroundings. A closed system exchanges energy but not matter with its surroundings.

Identify System Characteristics of Plants and Living Beings

Plants and living beings interact with their environment. They take in matter like nutrients and gases (such as CO2 and O2) and release waste and gases. Additionally, they exchange energy with their surroundings, such as absorbing sunlight or releasing heat.

Classify Plants and Living Beings

Given their characteristics, plants and living beings fit the definition of an open system. They both exchange matter (nutrients and gases) and energy with their environment. This characteristic aligns with the definition of an open system.

Key concepts

Open System

An open system freely exchanges matter and energy with its surroundings. This means substances can enter and leave the system boundary. Such a system is characterized by its constant interaction with the environment. Imagine a boiling pot of water. The steam (matter) escapes into the air, and heat (energy) dissipates into the kitchen. This movement of substances and energy is what defines an open system.

In real life, plants and living beings are prime examples of open systems. They take in nutrients, water, and gases such as oxygen and carbon dioxide from their surroundings.
They also emit waste and heat to the environment. Let's think about humans specifically. Every time we breathe, eat, or sweat, we are exchanging substances and energy with the environment. Such dynamic interactions keep open systems highly adaptable and constantly changing.

Closed System

A closed system is a step below an open system in terms of environmental interaction. It allows energy to move in and out, but not matter. A great way to visualize a closed system is with a closed soda can that is sitting at room temperature. The can may exchange thermal energy with the air around it but won't lose any liquid or gas unless it's opened.

In engineering, closed systems are frequently analyzed to maintain energy efficiency without allowing matter to escape. An example within nature would be the earth itself (considered as a nearly closed system) which receives energy from the sun but generally doesn’t exchange matter with space. Understanding closed systems helps engineers predict energy changes and design more effective thermal systems.

Isolated System

An isolated system is the ultimate in restriction. Neither energy nor matter can enter or leave. In practice, true isolated systems are rare or mostly theoretical, as even outer space isn't entirely insulated from external influences.

Thermos flasks are often used as real-world attempts to mimic isolated systems, though they are not perfect in doing so. Thermos bottles aim to keep their contents at a steady temperature for a long time by reducing the exchange of heat with the surroundings as much as possible.
Because isolated systems limit the exchange completely, they are ideal for studying the principles of conservation without external influences, making them very useful in theoretical physics.

Adiabatic System

Adiabatic systems are the focus of thermodynamics for not exchanging heat with their surroundings. They allow energy exchange in other forms, like work done or matter exchanged, but not through heat. Consider a rapidly compressed gas inside a piston. If compressed quickly enough, there isn’t time for the heat to escape. The gas gets hotter, but no thermal energy is exchanged with the surroundings. This is an adiabatic process.

For practical uses, adiabatic processes are critical in designing engines and refrigerators, where rapid changes in pressure and volume occur. This concept helps in understanding how energy efficiency can be maximized without the loss or gain of heat, keeping devices effective and consistent in their performance.