Absolute Zero

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An Absolute zero is the temperature at which particles constitute a minimal amount of heat. An absolute zero is also called the zero kelvin because it is zero on the Kelvin scale.

The value of the Absolute Zero in Fahrenheit is 459.76 degrees Fahrenheit, and the value of Absolute Zero in Celsius is - 273.15 degrees Celsius.

We call this the lowest temperature a thermodynamic system bears. However, the concept of Absolute 0 remains a theoretical concept.

In this article, we will learn about Absolute Zero Temperature in detail. 

Zero Kelvin

We say that an Absolute zero is the lowest value on the thermodynamic temperature scale. 

We can say that absolute zero temp is a state at which the enthalpy-and-entropy'>enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as zero kelvin. The basic particles of nature have the lowest vibrational motion, containing only quantum mechanical and zero-point energy-induced particle motion.

It is the point at which the Kelvin and Rankine temperature scale set their zero points at absolute 0. 

Absolute Zero Temperature

According to the classic kinetic theory, absolute zero represents the absence of movement of individual molecules in a substance whereas the experimental evidence shows this isn't the case, rather, it indicates that particles at absolute zero have the lowest vibratory motion. 

In simple terms, heat may not be removed from a system at absolute zero, there might be some heat stored in it, so it clearly states absolute zero does not represent the lowest possible enthalpy state.

In the field of quantum mechanics, absolute zero represents the lowest internal energy of solid matter in its zero/ground state.


Absolute 0 and Temperature

In Physics, we describe the hotness or coldness of an object with the term ‘temperature’

The temperature of an object depends on the velocity at which atoms and molecules inside it oscillate. Though absolute zero represents oscillations of atoms at the slowest speed; however, their motion never completely stops.

So, do you think is it possible to reach absolute zero or we can have an absolute zero in Fahrenheit and an absolute zero in Kelvin?

No, it is not possible to get an absolute zero in Fahrenheit and an absolute zero in Kelvin. However, scientists made it possible. Now, let’s understand how.

Absolute Zero Temp

From the above text, we got to know that reaching the absolute zero is not possible, though scientists have approached this level. 

Some of the record-breaking examples are as follows: 

Do you Know?

In 1994, NIST aka The National Institute of Standards and Technology achieved a record cold temperature of 700 nK, i.e., billions of a kelvin. 

In 2003, MIT aka Massachusetts Institute of Technology researchers set a new record of 0.45 nK.

Absolute 0 

Absolute Zero Temp can be thought of as the lowest temperature possible; however, it is not the lowest enthalpy state possible because all real substances begin to depart from the ideal gas behavior on being cooled as they approach the change of state to liquid, and then to solid; and the sum of the enthalpy of vaporization viz: gas to liquid state and enthalpy of fusion, i.e., change from a liquid to solid state exceeds the ideal gas's change in enthalpy to absolute zero. 

In the theory of quantum-mechanical, matter (solid) at absolute zero is in its ground state, i.e., the point of lowest internal energy.

Absolute 0 Temperature

As per the laws of thermodynamics, absolute zero cannot be reached using only thermodynamic means, it’s because the temperature of the substance being cooled approaches the temperature of the cooling agent asymptotically. Also, the system at absolute zero still bears quantum mechanical zero-point energy, i.e, the energy of its ground state at absolute zero. However, the kinetic energy of the ground state cannot be removed.

In the present era, Scientists and technologists daily achieve temperatures close to absolute zero, where matter exhibits quantum effects like superconductivity, superfluidity, and Bose-Einstein condensate, etc.


Absolute Zero Equations

While making a thermometer using a tube wall, we need to mark a scale on the tube wall with numbers on it. These numbers present a temperature scale. 

A temperature scale is a way to measure temperature relative to a starting point viz: 0 or zero, and a unit of measurement.

Here, zero represents the freezing point and 100 represents the boiling point. The units of measurement are:

  • Degree Celsius

  • Degree Fahrenheit

  • Kelvin

The absolute temperature scale that agrees to the Celsius scale is called the Kelvin (K) scale.          

The absolute scale that is analogous to the Fahrenheit scale is called the Rankine (R) scale. The zero points on both absolute scales (Celsius and Fahrenheit) represent the same physical state. The relationships between the absolute and relative temperature scales are described in the following equations:

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1. Kelvin to Celsius

K = °C + 273.15

°C = K – 273.15


2. Rankine to Fahrenheit

R = °F + 460

°F = R – 460

FAQ (Frequently Asked Questions)

Question 1: Can it be Possible to Reach a Negative Temperature?

Answer: Yes, it is possible to reach a negative temperature. 

Physicists have proved that it is possible to have a negative Kelvin/Rankine temperature. However, it does not mean that particles are colder than absolute zero; rather, it is an indication that the kinetic energy of particles has reduced.

We know that temperature is a thermodynamic quantity that is related to energy and entropy. 

As a system gains maximum energy, it starts losing its energy. However, this only occurs under special circumstances like in quasi-equilibrium states in which spin does not remain in equilibrium with an electromagnetic field. But in such activity atoms may have a negative temperature, even though energy is added to the system.

Question 2: Describe Absolute Zero in the Third Law of Thermodynamics.

Answer: According to the third law of thermodynamics, we can describe absolute zero in the following way:

The entropy (Here, entropy is the randomness of particles inside the system) of a system/substance reaches a constant value as the temperature approaches absolute zero. As per the empirical evidence, the third law of thermodynamics state that the entropy of a pure crystalline substance becomes zero at the absolute zero temperature, 0 K; however, it is impossible by means of any process, no matter how idealized it is to reduce the temperature of a system to absolute zero in a finite number of steps.