What is Entropy increase: Definition and 26 Discussions

Entropy is a scientific concept, as well as a measurable physical property that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynamics, where it was first recognized, to the microscopic description of nature in statistical physics, and to the principles of information theory. It has found far-ranging applications in chemistry and physics, in biological systems and their relation to life, in cosmology, economics, sociology, weather science, climate change, and information systems including the transmission of information in telecommunication.The thermodynamic concept was referred to by Scottish scientist and engineer Macquorn Rankine in 1850 with the names thermodynamic function and heat-potential. In 1865, German physicist Rudolph Clausius, one of the leading founders of the field of thermodynamics, defined it as the quotient of an infinitesimal amount of heat to the instantaneous temperature. He initially described it as transformation-content, in German Verwandlungsinhalt, and later coined the term entropy from a Greek word for transformation. Referring to microscopic constitution and structure, in 1862, Clausius interpreted the concept as meaning disgregation.A consequence of entropy is that certain processes are irreversible or impossible, aside from the requirement of not violating the conservation of energy, the latter being expressed in the first law of thermodynamics. Entropy is central to the second law of thermodynamics, which states that the entropy of isolated systems left to spontaneous evolution cannot decrease with time, as they always arrive at a state of thermodynamic equilibrium, where the entropy is highest.
Austrian physicist Ludwig Boltzmann explained entropy as the measure of the number of possible microscopic arrangements or states of individual atoms and molecules of a system that comply with the macroscopic condition of the system. He thereby introduced the concept of statistical disorder and probability distributions into a new field of thermodynamics, called statistical mechanics, and found the link between the microscopic interactions, which fluctuate about an average configuration, to the macroscopically observable behavior, in form of a simple logarithmic law, with a proportionality constant, the Boltzmann constant, that has become one of the defining universal constants for the modern International System of Units (SI).
In 1948, Bell Labs scientist Claude Shannon developed similar statistical concepts of measuring microscopic uncertainty and multiplicity to the problem of random losses of information in telecommunication signals. Upon John von Neumann's suggestion, Shannon named this entity of missing information in analogous manner to its use in statistical mechanics as entropy, and gave birth to the field of information theory. This description has been proposed as a universal definition of the concept of entropy.

View More On Wikipedia.org
  1. L

    Change of entropy in the Universe in a thermodynamic cycle

    (a) We first find that: ##T_A=\frac{P_A V_A}{nR}=\frac{1\cdot 10^5 \cdot 4}{40\cdot 8.314}K\approx 1202.7904 K##, ##\frac{T_B}{T_A}=\frac{\frac{P_B V_B}{nR}}{\frac{P_A V_A}{nR}}=\frac{P_B V_B}{P_A V_A}=\frac{P_A \frac{V_A}{2}}{P_A V_A}=\frac{1}{2}##, ##\frac{T_C}{T_B}=\frac{P_C...
  2. cianfa72

    I About Reversible vs Irreversible Gas Compression and Expansion Work

    Hi, reading the interesting Reversible vs Irreversible Gas Compression and Expansion Work insight by @Chestermiller I would like to ask for clarification on some points. In the second bullet at the beginning my understanding is as follows: consider an ideal gas contained in a cylinder...
  3. cianfa72

    I Entropy change due to heat transfer between sources

    Hi, starting for this thread Question about entropy change in a reservoir consider the spontaneous irreversible process of heat transfer from a source ##A## at temperature ##T_h## to another source ##B## at temperature ##T_c## (##T_h > T_c##). The thermodynamic 'system' is defined from sources...
  4. L

    Finding the increase in entropy of the universe in gas expansion

    a) ##P_f=\frac{nRT_f}{V_f}=\frac{nR\frac{T_i}{2}}{2V_0}=\frac{1}{4}\frac{nRT_i}{V_0}=\frac{1}{4}P_i## b) ##Q=\Delta U=nC_V \Delta T=n\frac{5}{2}R(-\frac{T_i}{2})=-\frac{5}{4}nRT_i=-\frac{5}{4}P_i V_0## (##L=0## since the gas expands in a vacuum;Now, (a) and (b) are both correct but not (c), for...
  5. Ebi Rogha

    A Block universe and entropy increase

    I wonder how physicists who support this theory explain the increase of entropy?
  6. li dan

    I Would this violate or challenge Newton's laws?

    The phenomenon of diffusion is a transport phenomenon based on the thermal motion of molecules, a process in which molecules are transported from a region of high concentration to a region of low concentration by Brownian motion. Let's assume that there is a car, the road under the wheels is...
  7. T

    Entropy increase of solid vs liquid

    A hypothetical question. Heat Q is transferred from water to a metallic solid. Both have same heat capacities and the same initial temperature. Now since molecules in a liquid are more randomly oriented than a solid, will the entropy decrease of the liquid be more than the entropy increase of...
  8. E

    Why does entropy increase when hot water is mixed with cold?

    Why is entropy lost by hot water less than the entropy gained by the cold water?From perspective of energy,why is it better to take water and heat it to a temperature than it is to mix hot water and cold water to get a particular temperature.
  9. MeneMestre

    Does entropy increase with improbability?

    Well, maybe that's a simple question, but it has been pissing me off for some time ... Does entropy increase with improbability?
  10. L

    Does entropy increase behind surface tension?

    Is there any entropic gain when the surface of a liquid is minimised? Per example, molecules "enjoy" maximum entropy when they are at the interior. Is this valid?
  11. I

    How can entropy increase in a deterministic universe

    Let's imagine a deterministic universe. A one where quantum mechanics simply doesn't apply. Ok. This was the universe of classical physics. Atoms exist, and they behave deterministically. Fine. Now, how can entropy increase in this universe, altough it has the same laws of physics. In a...
  12. E

    Heat and Entropy Increase Confusion

    This may be a matter of me being confused by the definition of heat. However, I view heat as the energy passed between systems of different temperatures. My problem is the following: By the principle of minimum energy/max entropy, in an isolated system (and therefore fixed internal energy)...
  13. S

    How does the universe so conspire that entropy increase?

    How does the universe so conspire such that ΔS≥0, entropy increases?
  14. I

    Various ways of doing work to minimize entropy increase

    [Moderator's note: Recategorized thread to "Basic".] While driving alone through the beautiful scenery of Banff and Yoho national parks, a question formed in my mind. Which of these modes of slowing down a vehicle by an equal amount is likely to minimize the resulting overall increase in...
  15. S

    Explaining the Stock Wave Entropy Increase

    Hi all Why the entropy increase across the stock wave.? How we can explain it Thanks
  16. PWiz

    Does electronegativity affect rate of entropy increase?

    Let's say we have two samples of pure Helium-4, and two other samples of pure hydrogen fluoride (consisting of Hydrogen-1 and Fluorine-19) all in separate containers. One container of each chemical is at the same initial temperature of 200°C at a pressure of 101kPa, and the other ones are at...
  17. J

    Entropy increase in adiabatic irreversible compression

    Hi there, I was wondering if you could help me, I think I may have some concepts wrong or incomplete. Homework Statement We have an adiabatic cylinder of volume ##V_1## filled with a gas of pressure ##p_1## and temperature ##T_1## in thermal equilibrium, closed with a piston. All of a suden...
  18. Art_Vandelay

    Entropy Increase of Aluminum

    Homework Statement Imagine that the temperature of 255 g of aluminum sitting in the sum increases from 278 K to 294 K. By how much has its entropy increased? Homework Equations Q=mcΔT ΔS=Q/T The Attempt at a Solution Q=(255 g)(.90 J/gK)(294 K -278 K) Q=3672 J ΔS=Q/T...
  19. U

    Does entropy increase in this process

    Homework Statement Is boiling of egg accompanied by an increase in entropy? The Attempt at a Solution I guess entropy decreases because as the egg boils, the stuff inside it gets hardened and changes into a solid mass. So the disorderliness decreases and the entropy should decrease. But...
  20. Z

    How Does Entropy Change During Gas Compression and Expansion?

    Suppose we have a closed cylinder with a partition. In one chamber is a gas, in the other is nothing. Now suppose we quickly remove the partition. The gas expands freely without work being done. Thus the entropy increases, because the gas doesn't "lose" energy. So that explains how a gas...
  21. B

    Entropy increase in dissipative systems

    Consider the following steady-state dissipative system. A mountain stream flowing 1 liter per second drops 100 meters over rocks and boulders, and at the bottom has both a temperature increase and a residual kinetic energy (velocity). The sum of the temperature rise and the kinetic energy is 980...
  22. M

    Entropy increase in gravitational collapse.

    I want to hear your opinion on this: Let's say that the universe in time zero consists just of a cloud of matter. Now as the time progresses, and the matter interacts gravitationally, it will gradually collapse into a sphere. Will the entropy of the universe really increase?
  23. L

    Does Removing a Partition Increase Entropy in a Gas Box?

    Suppose we have box with a volume V which is divided down its middle. So the box is split in two sides with equal volume (V_1 = V_2) and gas molecules (n_1 = n_2). Now, we remove the partition and the gas from both sides mix. Is there an entropy increase in the system? The whole process is...
  24. L

    Why is the phenomenon of increasing entropy not as straightforward as it seems?

    Can't the phenomenon of increasing entropy be explained as a result of the fact that in a collision of two particles the higher-energy particle always passes energy to the lower-energy particle (and never vice versa)? Hence energy becomes more evenly distributed in space...
  25. B

    What is the entropy increase per kilogram

    Homework Statement Suppose a power plant delivers energy at 9.7E2 MW using steam turbines. The steam goes into the turbines superheated at 665 K and deposits its unused heat in river water at 298 K. Assume that the turbine operates as an ideal Carnot engine. a. If the river flow rate is...
  26. T

    Exploring the Mystery of Black Hole Entropy Increase

    Supposing I started off with a particle, which I know exactly the state it is in, hence, it is in a pure state. And hence also, its entropy is zero. Now, suppose we throw the particle into the black hole and be sucked in, then, then the area of the black hole increases and hence, the entropy of...