What is Phases: Definition and 105 Discussions

In the physical sciences, a phase is a region of space (a thermodynamic system), throughout which all physical properties of a material are essentially uniform. Examples of physical properties include density, index of refraction, magnetization and chemical composition. A simple description is that a phase is a region of material that is chemically uniform, physically distinct, and (often) mechanically separable. In a system consisting of ice and water in a glass jar, the ice cubes are one phase, the water is a second phase, and the humid air is a third phase over the ice and water. The glass of the jar is another separate phase. (See state of matter § Glass)
The term phase is sometimes used as a synonym for state of matter, but there can be several immiscible phases of the same state of matter. Also, the term phase is sometimes used to refer to a set of equilibrium states demarcated in terms of state variables such as pressure and temperature by a phase boundary on a phase diagram. Because phase boundaries relate to changes in the organization of matter, such as a change from liquid to solid or a more subtle change from one crystal structure to another, this latter usage is similar to the use of "phase" as a synonym for state of matter. However, the state of matter and phase diagram usages are not commensurate with the formal definition given above and the intended meaning must be determined in part from the context in which the term is used.

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  1. U

    How electricity distributers achieve equal phase loads?

    How electric distributers achieve equal phases load, is this done by itself? Unequal situation hapend only in failure ? That depend on load, not source, but they cant control load.. so how?
  2. S

    I Fixing CP phases to cancel CKM phases

    When we try to see if the weak sector is CP invariant, we CP transform all the fields in the charged interactions terms and we get a condition involving the elements of the CKM matrix and the arbitrary phases of the CP transformed fields: $$V_{ij} = V^*_{ij} \, e^{i(\xi_W + \phi_{d_j} -...
  3. lionpauu

    A Do moon phases affect weighing precision on the microgram range?

    Hi, I'm looking to improve the precision of a system over a several hour cycle of operation of +50°C operation. The mass is ~11g and is suspended below the balance via a factory provided point. The "sample" is enclosed within a large borosilicate flask 150mm dia x 450 mm height that is trace...
  4. Talisman

    I What does decoherence have to do with phases?

    Here's the simplest example of decoherence I can think of. (I will drop normalizing factors for ease of typing.) Start with a state ##|\psi\rangle = |0\rangle + |1\rangle##. Measure it in the basis: $$|+\rangle = |0\rangle + |1\rangle, |-\rangle = |0\rangle - |1\rangle$$ It will always...
  5. A

    Sinusoidal sequences with random phases

    Hello all, I have a random sequences question and I am mostly struggling with the last part (e) with deriving the marginal pdf. Any help would be greatly appreciated. My attempt for the other parts a - d is also below, and it would nice if I can get the answers checked to ensure I'm...
  6. W

    I History of astronomy and the Phases of Venus

    Does anyone know when it was first realized that a heliocentric model of the cosmos should show the phases of Venus in the way Galileo saw them in the 17th century.?Was it known in the time of Aristarchus or did people only realize this was a consequence of helicoentrism later on, perhaps only...
  7. M

    What are some possible future applications for supersolids?

    Scientists finally created a 2D Supersolid! There existence has been predicted since the 60’s and now we have them. The scientists who created it don’t really know what it could be used for as it’s so much in the infancy stages, it’s practically a zygote. As an aspiring futurist, I was wondering...
  8. B

    Help With Negative Phases in a Numerical Term

    I think I've got the numerator part figured out, but I'm really stuck on what to do with those negative phases in the last term and how to get this to all come together in the end. I feel like I must have made a mistake somewhere, but can't find it. Thanks in advance for the help!
  9. LCSphysicist

    Standing waves on a string -- Find the difference of phases

    The immediate thing i did here is ## \Delta \varphi = k(\Delta x) ## Interesting enough for a topic, if you use this equation you end up wrong like me, the answer is not D. Not sure what is the problem.
  10. Rahulx084

    Thermodynamics: Single/Homogeneous Phase Differences

    #Can somebody please explain what is the difference between single phase and homogeneous phase in context with thermodynamics? #Also in the fundamental relations in thermodynamics like dg=vdp-sdT , it says this is applicable to homogeneous phase of constant composition. Isn't this equation...
  11. entropy1

    Randomizing phases of harmonics

    Suppose I decompose a discrete audio signal in a set of frequency components. Now, if I would add the harmonics I got, I would get the original discrete signal. My question is: if I would randomize the phases of the harmonics first, and then add them, I would get a different signal, but would it...
  12. J

    Volume fraction of multiple phases

    Afternoon all, Hopefully somebody can help me, I'm doing my final year project and it's looking at the effect of heat treatment on in17, when I run an XRD scan I found that I all the phases sort of hid behind the matrix and so can't really make them out. So I've been looking at using the SEM...
  13. kolleamm

    Why do the phases of a motor spin the rotor?

    Assuming we have a 3 phase motor I've always wondered why is it that the rotor spins rather than just being compleltly pulled towards the direction of the phase or the electromagnet? What causes that angular movement?
  14. H

    I Superposition of Phases: A Key Concept in Connecting QFT and Statistical Physics

    Homework Statement: relation between qft and statistical physics Homework Equations: domains with equal values I read a french paper about Kenneth Wilson. i translate several sentences (with google): it was demonstrated in 1960 by Kenneth Wilson that renormalization formed an incongruous...
  15. Baibhab Bose

    Phase transition between two phases with different Cv

    I actually can't figure out what kind of phase transition it is and how to proceed through..!
  16. A

    A Are there conditions for the vanishing of geometrical phases in QM?

    Are there theorems for sufficient and necessary conditions for the vanishing of Berry and/or Wilzeck-Zee phases for a given quantum mechanical system?
  17. A

    A Crossing degeneracies and geometrical phases

    Assume all the usual things for the usual things for the geometric phases: A Hamiltonian that depend on external parameters, Adiabatic evolution, cyclic evolution in parameter space and all that If through the evolution in parameter space there is no energy level crossing, then a eigenvector of...
  18. Demirci Kawa

    B Phases of Matter: Solid, Liquid, Gas & More

    I read a physics book, it says here that... " Matter appears in three different phases that we call solid, liquid, and gas" How about plasma?
  19. Z

    Carbon dioxide in liquid and gaseous phases with liquid water

    What are the differences between carbon dioxide solubility (miscibility, reaction) in liquid water when in gaseous (<38 bar) and liquid (>38 bar) phase? The temperature in my experiments is usually between 0 and 5°C. The stirring speed is around 500 rpm. Is the solubility given apart from...
  20. S

    A Topological Phases: Understanding Kitaev's Paper

    Dear All I am trying to understand the following paper for Kitaev :" Periodic table for topological insulators and superconductors", But i am founding it so hard. Can anyone help me to understand it? Thank you.
  21. T

    Phases of hydrocarbons in a compressed gas cylinder

    I'm currently in the process of selecting gas mixtures to calibrate a gas chromatograph. One of the gas mixtures I'm interested in has the following composition by percent volume: methane (CH4): 95% carbon dioxide (CO2): 1% butane (C4H10): 1% acetylene (C2H2): 1% nitrogen (N2): 2% The gas...
  22. D

    A Phases Of Adjoint QCD_3 And Dualities

    Here is an interesting paper where they uncover new dualities by studying adjoint QCD in 2 + 1 dimensions. https://arxiv.org/pdf/1710.03258.pdfPhases Of Adjoint QCD_3 And Dualities by Jaume Gomis, Zohar Komargodski, and Nathan Seiberg We study 2+1 dimensional gauge theories with a...
  23. J

    Quantum Are there any good books on Geometric Phases in Quantum Mechanics?

    Hello! I would really appreciate it if somebody could recommend to me any books on geometric phases especially on Berry's phase. Thanks!
  24. J

    Quantum Book on gauge transformations/symmetry & geometrical phases?

    Hello! I will be attending a course on condensed matter physics with emphasis on geometrical phases and I was wondering if the are any good books on gauge transformations, gauge symmetry and geometrical phases that you know of. Thanks in advance!
  25. F

    Water and its interesting 3 phases....

    Hello Forum, I am reviewing water and its 3 phases (solid, liquid and gas). a) At the triple point, water can be in the three phases simultaneously. Does that mean that for a certain amount of water, say 30grams, we would find, approximately, 10 grams of liquid water, 10 grams of ice and 10...
  26. T

    AC Mains Inverter Refresher: exotic advantages?

    Hi, Could I please get some conformation and clarification: So the more phases an inverter has, the less ripple will be on the DC bus, and the higher the switching frequency the inverter is operating at, the closer the approximation is to a sine wave. These are the advantages? But what are the...
  27. Z

    B Are Lunar Phases Affected by Earth's Orbit and Rotation?

    My first question is: Shouldn't the lunar phases be thrown off by Earth's orbit of the sun? As in, after 6 months of orbit, since we are on opposite sides of the sun, the phases would be reversed so that the moon being in the same position relative to the Earth as it was before the 6 months...
  28. T

    Why Do We Subtract Densities in Surface Tension Calculations?

    From a textbook: I don't quite understand the part where the difference of densities is taken, could someone explain that for me? Thanks.
  29. Philethan

    Is dn = dS = 0 when two phases are equilibrium?

    Hello, every one! I'm studying the Section 9.2 - Phase Equilibrium of "Classical and Statistical Thermodynamics" written by Carter. In equation (9.21) and (9.22) He said: dS_{A}=\frac{1}{T_{A}}(dU_{A}+P_{A}dV_{A}-\mu _{A}dn_{A})-----(9.21) dS_{B}=\frac{1}{T_{B}}(dU_{B}+P_{B}dV_{B}-\mu...
  30. Ricardo Luis

    Phase diagram p-v and plasmatic state

    phase diagrams show the change of the state when temperature or pressure are modified. to achieve this, is necessary heat, but my questions is: would plasma state be described in this diagrams? is this figure true? because plasma state can be generated by heating.
  31. I

    Energy of particles in three phases of matter

    This is a restatement of a question I have been pondering whilst helping my daughter with GCSE physics. My previous post didn't get me the closure I was after so am trying again. I have three different GCSE textbooks. All three have a simple section on the kinetic theory of particles in...
  32. T

    Exploring the Benefits of 6 Phase Inverters: A Scientist's Perspective

    Simple question, What's the advantage of having more phases in an inverter? Like why have 6 or twelve phases? Is it something to do with harmonics? I know that the higher the switching frequency the further off in the freequency spectrum you can push the harmonics, but I can't see that being...
  33. TheExibo

    How was Galileo able to observe Venus's phases?

    Another piece of compelling evidence of the existence of a heliocentric solar system was the discovery of Venus's phases by Galileo Galilei. How was Galileo able to observe these phases with the Sun in the way? Did he simply view only early waxing and late waning phases? I find it questioning...
  34. L

    Adding waves of the same frequency but different phases

    Homework Statement how do you add two waves with the same frequency but different phases? E1 = 7*sin(omega*t + 70degrees) E2 = 13*sin*(omega*t + 65degrees)[/B]Homework Equations Er = E1 + E2[/B]The Attempt at a Solution I know how to add waves that only have one phase, i.e. E1 =...
  35. J

    Sources to learn about Berry phases and Adiabatic Theorem

    Hello, I recently went through Griffiths' Quantum Mechanics text and there is a chapter called the Adiabatic Theorem that includes Berry phase and the Aharonov-Bohm effect. As I found them very interesting, I would appreciate if anyone could provide me with some good sources(books, internet...
  36. A

    Compare Energy Consumption for different phases of a system

    I wish to compare energy consumption of my protocol, in embedded systems, in two different phases. The point is that one phase lasts longer than other (around 130 seconds more). => The longer phase will, of-course, have larger energy consumption since time is a higher quantity in this case. Can...
  37. J

    Caculation of line current on a 3 phases unbalanced delta

    Hello, I cannot find back from school, the formula to use: A 3 phases 220Vac system, no neutral, 3300W of pure resistance load between L2 and L3, the same load between L1 and L3, nothing between L1 and L2. What will be I1, I2, I3 the current in the 3 lines of the network? Thanks in advance -- Jmp0
  38. T

    Two moons in tidal lock orbit: phases, tides, axial tilt?

    Consider the following; We have Earth with two moons in orbit (discounting the existence of our own moon for the sake of this hypothetical scenario). One moon is the size and mass of Pluto, orbiting around 70,000km from Earth. The other is the size and mass of Pluto's moon, Charon, orbiting...
  39. mpapachristou

    Proof verification of EF/MF phases

    1. Statement: Prove that the EF and the MF are in phase far away from an oscillating electric dipole Homework Equations : The oscillatory motion equations for charges (q(t) = q_0sin(ωt) etc.)[/B] The Attempt at a Solution : Attached PDF file[/B]
  40. T

    Are Triple Points and Critical Points Theoretical or Observable in Real Life?

    I just read an article with a phase diagram, and I am curious if triple point and critical points are SIMPLY theoretical (just in mind) or are they possible in real life (observable in real life)? I understand what they represent, but I am curious.
  41. L

    Question about stationary and mobile phases

    We have been learning about HPLC and GC machines, and discussing the various types of columns, and I felt that everything was pretty clear and obvious. However, something from yesterday made me a bit confused, so I am hoping for some clarity. If you have a polar stationary phase, and you want...
  42. E

    Regression Analysis of Tidal Phases

    I have some 3-D model output for a river system that is tidally forced at the entrance. Right now, I'm trying to perform some linear regression on the harmonic constants of various tidal constituents at for several locations along the river compared to the observed tidal data. A linear...
  43. J

    Three Phase Generator: Knowledge Sharing

    Dear all, please could you share with me your knowledge about three phases generator? I would like to know exactly how current flow back to generator. For example what is exact way of current from generator (1). What line is using as return path for it. And also do not know how it is possible...
  44. L

    Bubble in Liquid: Phase Change Under Pressure?

    Anyone , what the bubble in the fluid will be if we compressed the fluid with high pressure? for example the fluid is oil with high viscous. does the bubble change in phase? (condense)
  45. A

    Moon Phases: Rise & Set Timings & Direction Explained

    Hello! Why does the moon has different rise and set timing for different phases? And also, why does it rise from different directions during different phases? Help me out please!
  46. P

    Syncing 2 Phases - Energy Monitor DIY Arduino

    Hi all, Doing some energy monitoring of some various equipment using ct clamps and an diy arduino based energy monitor. I have limited number of arduino inputs available so have been experimenting to boost the capacity of the monitor without using multi arduino. I have found no problem...
  47. M

    Understanding Phases and Properties in a Phase Diagram

    Hi, all. In the picture is a question and its solution. Here I can not understand how is the graph Ln P versus T established why are there only liquid and vapor parts how can be understand solid phase should not be there and when the properties under the critical ones why is it written as...
  48. M

    Gibb's phase rule and counting phases

    Hello, I was wondering, suppose I had a mixture of a few liquids that were immiscible, say 4. Now, when calculating the degrees of freedom, I am confused about the number of phases. I think the number of components is 4, but the number of phases should be 1, liquid, right? Or does each...

    Phases of the Moon: Amateur Questions Answered

    amateur question. referring to the following link Lunar phase - Wikipedia, the free encyclopedia (particularly the video on the bottom right) I understand what's going on except one thing, why don't the phases of the moon change overnight? is it the scale of the video that is probably...
  50. V

    Transformers - question about number of phases used

    transformers -- question about number of phases used why often single phase and three phase transformers are widely used rather than other phases like four,five phases