Questions tagged [phase-transition]

A phase transition is a change in the nature of a phase or in the number of phases of a system as a result of a change in the external conditions. Examples: melting/freezing, vaporization/condensation, ferromagnetic transition, superconducting transition.

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Strange ice found in my garden

This morning I found a really strange ice formation in my garden. I can't figure out how it appeared, because there was nothing above. The night was particularly cold (Belgium). To give an idea, it ...
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Why does ice cream get harder when colder?

What would seem to be a silly question actually does have some depth to it. I was trying to scoop out some of my favorite soft name-brand ice cream when I noticed it was frozen solid, rather than its ...
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Why does matter exist in 3 states (liquids, solid, gas)?

Why does matter on the earth exist in three states? Why cannot all matter exist in only one state (i.e. solid/liquid/gas)?
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Why does water stop boiling immediately after turning off the heat?

When I am heating water on a gas stove, it begins to boil after some time and bubbles of air can be seen escaping out. However, as soon as I increase the amount of heat in the stove, the rate of ...
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First and second order phase transitions

Recently I've been puzzling over the definitions of first and second order phase transitions. The Wikipedia article starts by explaining that Ehrenfest's original definition was that a first-order ...
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When I boil a kettle, what stops all the water from turning (exploding!) in to steam in one go once it reaches 100°C?

While making a cup of tea in the office kitchen, a colleague asked me this question and neither of us could answer with any certainty. We're guessing it has something to do with the pressure of the ...
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Why is boiling water loud, then quiet? [duplicate]

Water in my electric kettle makes the most noise sixty to ninety seconds before the water comes to a full boil. I have been fooled many times by the noisy kettle, only to discover that the water was ...
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Can Lee-Yang zeros theorem account for triple point phase transition?

Now the prominent Lee-Yang theorem (or Physical Review 87, 410, 1952) has almost become a standard ingredient of any comprehensive statistical mechanics textbook. If the volume tends to infinity, ...
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What happens when you put water under intense pressure?

Pretend you have an indestructible tube that cannot leak, inside which is water. Imagine that in each side of the tube, you have very powerful pistons What would happen if you compress the water ...
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What's the rigorous definition of phase and phase transition?

I always feel unsure about the definitions of phase and phase transition. First, let's discuss in Laudau's paradigm. For example, some people say that phase is classified by symmetry. Some people say ...
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Why does snow stay after a snowfall?

I have just experienced a snowfall and I am not so clear on how it works. Three days after a short day of snowfall, and having 2 min | 17 max degrees Celsius, full sunny scarcely cloudy each day, ...
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Why does a critical point exist? [duplicate]

I still cannot fully comprehend the essence of a critical point on phase diagrams. It is usually said in textbooks that the difference between liquid and gaseous state of a substance is quantitative ...
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Why is there more steam after a pot of water *stops* boiling?

I have a pot of vigorously boiling water on a gas stove. There's some steam, but not alot. When I turn off the gas, the boiling immediately subsides, and a huge waft of steam comes out. This is ...
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Why does temperature remain constant when water is boiling?

As I understand it, during boiling the input of heat destroys or re-arranges the hydrogen bonds. It is used, in other words, against the potential energy of the intermolecular bonds. But if some ...
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Paradox regarding phase transitions in relativistic systems

The main question I would like to ask is whether quantities such as density are dependent on the frame of reference. I have searched several forums and the answer is somewhat controversial. Some ...
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Why is the melting point of water independent of pressure?

I've read here that the boiling point of water is highly dependent on the pressure, whereas the melting point is independent of the pressure. Why is that? Is that true in general?
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Freeze water in red-hot container

While reading Edgar Allan Poe's short story The thousand-and-second tale of Scheherazade (about a fantastic journey to the present of 1850) I once stumbled on the following footnote to the phrase "...
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Why do ice crystals form from the top to the bottom of a bottle filled with supercooled water?

If I bang a bottle filled with supercooled water against a hard surface, the ice crystals form from the top to the bottom:$\hspace{50px}$$\hspace{75px}$–source. YouTube has videos showing this ...
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Does providing more heat to a pan of boiling water actually make it hotter?

Sometimes my wife has a pan of water 'boiling furiously'. Is the extra heat (wasted in my opinion) actually making any difference, apart from reducing the amount of water in the pan - which could be ...
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Is a single radon-daughter atom in air, such as ${}^{218}\text{Po}$, a solid?

Is a single radon-daughter atom in air a solid? The Wikipedia article on radon says: Unlike the gaseous radon itself, radon daughters are solids and stick to surfaces, such as dust particles in ...
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Does any substance melt or evaporate when cooled at constant pressure?

Is there any substance with segments of its phase change diagram lines going in a negative direction? To explain: Generally, as phase change diagrams go, with heat increasing, and pressure constant, ...
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Why does water ($\mathrm{H_2O}$) only have two distinct fluid phases?

Water (and other substances) can exist in many distinct solid phases (with different crystallic micro-structure), but only in two fluid phases - liquid and gaseous, in which the molecules are oriented ...
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Does this type of phase transition exist?

The short version of this question is: Is there, or could there be, a system with a phase transition where adding a small amount of heat causes a discontinuous jump in its temperature? Below are my ...
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Why would different metals glow red at different temperatures?

According to everything I've been taught about incandescence and black-body radiation, and some quick Googling to confirm I'm not crazy, just about everything, regardless of composition, should start ...
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What is the Kosterlitz -Thouless transition?

I couldn't find any simple texts explaining the Kosterlitz-Thouless transition. More specifically can someone explain the role of vortices in the transition. edit: links explaining the transition in ...
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Besides water, which substances are less dense as solids than as liquids? [duplicate]

You can read everywhere about water's extraordinary property of expanding when frozen, thus the reason ice floats on liquid water. What other substances do this? There are claims of mercury, silica, ...
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Symmetry Breaking And Phase transition

Is every phase transition associated with a symmetry breaking? If yes, what is the symmetry that a gaseous phase have but the liquid phase does not? What is the extra symmetry that normal $\bf He$ has ...
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What is “Dynamical phase transition”?

What is "Dynamical phase transition"? It is a fancy notion now. But what exactly does it mean? What is the difference between it and the conventional phase transition?
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What are Griffiths effects in the context of condensed matter physics?

From a cursory examination of the literature I've gathered the following: it seems that ordered systems have a "clean" critical point, at which the system makes a sharp phase transition, and that ...
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Phase Transition in the Ising Model with Non-Uniform Magnetic Field

Consider the Ferromagnetic Ising Model ($J>0$) on the lattice $\mathbb{Z}^2$ with the Hamiltonian with boundary condition $\omega\in\{-1,1\}$ formally given by $$ H^{\omega}_{\Lambda}(\sigma)=-J\sum_{...
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Phase transition water

The water-gas phase transition is said to be similar to the ferromagnetic-paramagnetic phase transition (same set of critical exponents = same universality class). In the former case the order ...
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Ice cube left in water at 0 °C for a thousand years

Let's say we take an ideal calorimeter with a liter of water at +5 °C and throw a 5×5×5 cm cube of ice having temperature of –70 °C. I choose these initial parameters so that the stationary ...
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How does the Kosterlitz-Thouless transition not violate the Mermin-Wagner theorem?

The Mermin-Wagner theorem states that continuous symmetry cannot be spontaneously broken at any finite temperature in two dimensions or lower. The Kosterlitz-Thouless (KT) transition is a phase ...
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Definition of phase transitions in statistical mechanics

Phase transitions in statistical mechanics are usually taught by working through a bunch of examples. I decided to try and think about them from a more "fundamental" point of view - but I've run into ...
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What is crossover?

It is known that electroweak and QCD phase transitions in the standard model are so-called “crossovers” [1]. What is the difference between a crossover and a phase transition of the second kind? [1] ...
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Fluids with critical point at ordinary temperature and pressure

Are there any fluids with critical point near STP or that are supercritical at STP? If not would it be feasible to design a molecule for a substance with critical point near STP using theoretical/...
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Do all phases of ice look the same visually?

I recently read about different phases of ice on Wikipedia. But I can't find any pictures of the different ice phases. Do they all look alike visually? If you weren't able to measure the pressure and ...
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Boiling point of barbecue sauce

Yes, I am serious. I thought it was interesting that I was reducing some fluid the other day, and I put in my alerting thermometer to warn me of a rising temperature which I expected as the water ...
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Understanding the $\phi^4$ phase diagram

I'm having trouble making sense of this phase diagram. The model is a $V(\phi)=g_2 \phi^2+g_4\phi^4$ scalar field theory. Here's what I think I understand: the capital letters represent different ...
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Burning Fuels and Producing Water

I have a question about Optics and how this links to burning fuels in a combustion reaction. If I have hexane, the following reaction occurs: hexane + oxygen $\rightarrow$ carbon dioxide + water ...
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Are there published predictions that hydrogen could remain metallic at ambient pressure?

Below the question For the recently reported production (January 2017) of metallic hydrogen in the laboratory - what is the evidence exactly? there is a comment that directed me to the BBC News ...
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How to freeze the Niagara waterfalls?

Here is a picture of the usual vigorous Niagara Falls (in the winter). Here is the picture of Niagara Falls frozen in 1933 (in the very cold winter). Here is the picture of Niagara Falls frozen in ...
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Are the first order phase transitions always associated with a latent heat?

Is the first order ferromagnetic transition below the critical temperature associated with latent heat? For example, the transition of ferromagnetic configuration with all its spins aligned up to a ...
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Discontinuities and nondifferentiability in thermodynamics

In physics and engineering sources, calculus-based formalisms - whether differential forms on a manifold, or "differentials" of functions of several variables - are presented as a way of modeling and ...
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Demystifying jamming in many-body systems

From a theoretical point of view, what has been the most successful approach to understanding jamming phenomena? I understand there's still a lot of debate around this subject, namely whether a ...
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Could a gas go directly to a solid without becoming a liquid?

If water vapor is pulled inwards and cooled at a fast enough rate could if be frozen back into a solid form? i understand that they would have to be froze together as soon as contact is made but if ...
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What leads to the existence of critical temperature?

We know that $T_c$ is the temperature above which no amount of pressure could force a gas to liquefy. But why is this? Somehow I don't buy the point that the gas molecules exert too much pressure ...
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What is the real cause of the boiling (forming of bubbles) of water?

I've got a question about the boiling of water. I'm a first year physics student and from the Netherlands. I've searched alot about the boiling of water and this confused me. Everyone said something ...
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What did electroweak symmetry breaking actually look like?

Approximately one picosecond after the Big Bang, the universe cooled down enough to pass through the electroweak phase transition. At this point the Higgs mechanism kicked in, the weak force became ...
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Ice cube in a thermally isolated system … Will any of it melt?

If an ice cube at $0$ °C is in a thermally isolated system on its own, will any of it melt? The chemistry teacher says it will reach a state of equilibrium of half ice and half water due to ...