What is Absolute zero: Definition and 129 Discussions
Absolute zero is the lowest limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as zero kelvins. The fundamental particles of nature have minimum vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion. The theoretical temperature is determined by extrapolating the ideal gas law; by international agreement, absolute zero is taken as −273.15 degrees on the Celsius scale (International System of Units), which equals −459.67 degrees on the Fahrenheit scale (United States customary units or Imperial units). The corresponding Kelvin and Rankine temperature scales set their zero points at absolute zero by definition.
It is commonly thought of as the lowest temperature possible, but it is not the lowest enthalpy state possible, because all real substances begin to depart from the ideal gas when cooled as they approach the change of state to liquid, and then to solid; and the sum of the enthalpy of vaporization (gas to liquid) and enthalpy of fusion (liquid to solid) exceeds the ideal gas's change in enthalpy to absolute zero. In the quantum-mechanical description, matter (solid) at absolute zero is in its ground state, the point of lowest internal energy.
The laws of thermodynamics indicate that absolute zero cannot be reached using only thermodynamic means, because the temperature of the substance being cooled approaches the temperature of the cooling agent asymptotically, and a system at absolute zero still possesses quantum mechanical zero-point energy, the energy of its ground state at absolute zero. The kinetic energy of the ground state cannot be removed.
Scientists and technologists routinely achieve temperatures close to absolute zero, where matter exhibits quantum effects such as Bose–Einstein condensate, superconductivity and superfluidity.
HeyI was wondering - is it physically impossible to make something absolute zero and then measure it to check if it was?
I often read that we bring things down to "close to absolute zero" but it never is the full way.
Is it because if human or electronic device, which ever it was that tried to...
I was wondering, since resistance decreases along with temperature for most metallic conductors (usually power function), in theory, if this conductor were to be at zero kelvin, would the resistance of this material also be precisely zero, or would it just be some extremely small value?
If it...
I'm trying to figure out why things happen to objects placed in environments near absolute zero. so let's take an ice cube. In a freezer it will remain stable, I'm guessing because the atoms that make up the ice cube will bounce off atoms in the air that are roughly similar in energy to the...
Title says it all. I've been wondering.
The argument is, is there a minimal temperature required for any chemical reaction to reach its activation threshold?
Or would the energylessness of the atoms prevent bonds from forming (or dissolving, I guess)?
Conrad.
We were presented with a task of calculating the temperature of absolute zero experimentally.
To do this, we were given a capillary tube with one end sealed. Then we heated the tube up in a bunsen burner and quickly put the open end in some cooking oil. The oil was sucked up as the gas within...
Hi,
I understand for metals the conduction band is usually partially filled.
However, at absolute zero, is the conduction band empty (for metals)?
I'm asking this because as far as I know, the definition of valence band is "the highest occupied band at absolute zero"
However, I have...
Is it weird that at absolute zero in a metal, electrons at the fermi level still move around at the fermi velocity.
Is the notion that everything stops at absolute zero incorrect?
Thank you
As a semi conductor approaches absolute zero there should be zero conductivity, the thermal energy that electrons acquire is or can be responsible for promoting electrons from the valence band to the conduction band to provide current flow in a semi conductor ( for t>0).
My question is...
I know that water forms different kinds of crystals in different kind of temperatures but is there any temperature where water is solid but does not form crystals for example just above absolute zero degrees, what kind of crystals does it form?
I'm not a scientist, but I really enjoy reading the perspectives on these boards. I have some questions I hoping to hear a lot of perspectives on.
I know absolute zero has never been reached, but in what ways are we attempting to find absolute zero currently?
If, hypothetically, we were...
Hi,
Today in school I performed an experiment that went like this:
We had a capillary tube with trapped air on the bottom, the top part was open to the atmosphere and, in between, there was some sulphuric acid.
We heated the capillary tube and recorded the increase in volume of the trapped...
This is highly theoertical and I came up with it taking a standerized test. So without further adoo,
What would happen if you to a cyrogenic chamber froze something to ablsolute zero and put it on a spacecraft moving at exactly the same velocity as the universe is. Thus canceling out...
When something is frozen fully, and the temperature is absolute zero -there is no entropy - but does that mean the "quantum jitters" are not occurring?
I was just wondering. With the Twin Theory, with the person traveling at the speed of light causes them to age slower. So I wondered, does that mean that something would age faster if at absolute zero? Because I've heard that motion is relative to temperature, and time is relative to velocity...
According to Charles' law, volume decreases with temperature. Extrapolating down towards absolute zero, and the volume of the gas will be zero.
How can this be possible? Surely any amount of gas will still have to take up some volume in space. Can multiple gas molecules really occupy zero volume?
Absolute Zero, about -273.15ºC, is the coldest known temperature possible, where matter it's self, stops moving, and energy can't build up. But, could there be...say, an absolute ∞? Or like...and Absolute energy? Could these be physically possible, and where would these things be found. What...
Hi everybody, I would like to begin with apologizing for anything stupid I might say or ask because I am not a qualified physicist. I'd like some minutes of your time because i have a question that's been on my mind far too long and i would really like some help with this.
Am I correct when I...
i am in the 9nth grade and i am intrigued by the idea of Absolute zero and the phenomenas, my question is what will happen if we reach absolute zero? i know that molecules slow down until they stop, but i don't understand one thing, what is keeping the atoms together, isn't it energy. is there...
i am not exactly sure what happens when the temperature almost reaches absolute zero how things react to this drop and what are boson ( sorry for spelling errors)
Homework Statement
A constant-volume gas thermometer is cal-
ibrated in dry ice (which is carbon dioxide
in the solid state and has a temperature of
−80◦C) and in boiling ethyl alcohol (78◦C).
The two pressures are 1 atm and 1.542 atm.
What value of absolute zero does the cali-
bration...
Is the uncertainty principle enough to prove that absolute zero is unachievable? i.e. a particle can't be said to have exactly zero energy, because it can't be said to have exactly any amount of energy.
Alright, Could you use magnets to slow matter down enough to reach "near" absolute zero? Heres how it would work. You would have a range of magnets in a chamber, and you would inject the chamber with protons. The magnets are comeing from all directions forcing the proton to stay still. Then...
Show that the kinectic energy of a three-dimensional fermi gas of N free electrons at absolute zero is (Mathematica code used)
u = 3/5 N Subscript[\[Epsilon], F]
Now I know total energy of N particles is this integral
u = \!\(
\*SubsuperscriptBox[\(\[Integral]\), \(0\)...
I hear how people create superconductors by taking a metal and freezing it to Absolute Zero(0 Kelvin). What are some methods to get this sort of tempuature? Can anyone help?
Hello colleagues, I have a seminar that i need to turn in a weeks day from now.
My professor listed the following questions, guidelines that I should lean on:
1) Is it possible to achieve a temperature bellow absolute zero (-273,15)
2) An ideal gas contracts linearly when decreasing...
If time requires movement in space time in order for change and hence time to occur then how does absolute zero in temperature effect time since no molecular or atomic movement is possible at such temperature?
Does vibration constitute movement that can affect time in relativistic terms?
Is it...
I don't need help with a numerical solution here - mostly a concept check.
I've been asked to calculate the speed of sound in metallic sodium at T = 0 K using Fermi-Dirac statistics.
After doing so, I get a speed of 14.5 meters per second, which is, well, really slow.
I would have...
Homework Statement
Calculate your experimental value of absolute zero , how does your experimental value compare to the theoretical value -273C?
Homework Equations
T_abs=(S1*T2-S2*T1)/(S1-S2)
The Attempt at a Solution
This is all part of a lab. I'm not asking people to do any...
I was thinking, if time passage varies with speed would the speed of atoms random movement (temperature) affect time? For example, if the universe is expanding, as some predict, it will eventually reach a state where everything will reach very near to absolute zero, or maybe absolute zero. If it...
I am working on a lab report related to Ideal Gases at the moment, and I can't quite grasp how you would go about finding the temperature for absolute zero. Here's a brief synopsis of our experiment: We inserted a piston into a cylinder of water to keep the piston at a steady temperature of 23...
This is either a topic that is so blatantly obvious that it's ridiculous I'm saying it, or I'm missing something. From my limited physics knowledge, I know that absolute zero is a temperature in which the molecules are not moving whatsoever. In other words, it's the lowest possible...
Hi ,
Please help me to solve following problem.
If 20 KJ are added to a carnot cycle at a temperature 100 degree Celsius and 14.6 KJ are rejected at 0 degree Celsius,determine the location of absolute zero on celsius scale?
Ans -270.16 C
Please tell me how to solve it
Thanks in...
This problem seems straightforward and easy enough, but I still want to check my answers.
Suppose the pressure of the bulb (light bulb I'm guessing used in experiment) is 20 psi (absolute) at 20C. What would you predict the pressure to be at 0C? What would you predict would be at 100C?
I...
i have read in some articles that when 0 Kelvin is achieved then particle movement within the cooled substance ceases. but my doubt is that einstein said that all objects have constant movement. this means that if the particles really stop then they will kind of stop in time because it is longer...
Why are we finding it so difficult to reach absolute zero and if at all we are able to achieve it then what are the implications of such a feat?
What relation does a bose einstein condensate have with absolute zero? (i know that we have achieved it but how does it happen as we lower temperatures)
Today in my physics class we got into a discussion about Absolute Zero and gravity. The argument was that if Absolute Zero was achieved, would it still be affected by gravity? Because gravity is a force and would make whatever that was at Absolute Zero move, but to have motion there would be...
I've been told that as a person approaches the speed of light, time relative to others being viewed slows. when you make the speed of light ( if possible, I’m aware of distance change and mass increase and of the immense amount of energy needed to possibly reach this speed to push that mass)...
Homework Statement
ive been thinking about this for some time but can't find an answer...
gas enters a bottle at a very low pressure, and high temperature, to maximise space between particles. the bottle is then sealed off and the temperture drops to absolute zero, does the gas become solid...
(i have next to no knowledge about physics so please don't beat me down my there are flaws in my theories)
as they say, time is defined by movement. you might say, "my eraser is perfectly still in my freezer (why you would put it there is beyond my comprehension)" be we are still moving on...
I am not sure if I should be posting this in another section, but my question is this:
Does the uncertainty principle necessarily prevent a temperature of absolute zero occurring anywhere in the universe?
I am no physics expert, just curious really.
Liam
Hi,
I'm currently doing an A level course in Physics, so this thought struck me then.
I was looking at a simple problem, when a thought struck me, if V=I/R and at absolute zero (0 kelvin) there is no resistance, what happens to the voltage?
In other words, V=I/0 I know that you cannot...
Hello all
This question is probably a bit ridiculous, but here goes:
Hypothetically, If any given closed system has obtained absolute zero temp, does any media (time, gravity, events)occur within? Thermodynamically, Wouldn't this be a state of infinite entropy? Can anyone describe such a...
I am aware that absolute zero can not be achieved by cooling a substance since absolute zero is zero-point energy. I was just wondering what is used (coolant wise and apparatus wise) to cool something near this temperature since there some experiments such as the Boise-Einstein Condensates which...