Absolute zero means what?

Answer 1

Much to be written about this. It is the temperature, about -293.15 Celsius, at which gases theoretically have a zero pressure at constant volume. In theory, absolute zero, the point where all motion stops, is not reachable.

Answer 2

Absolute zero as regards to temperature? It has to do with atoms. Atoms in any substance are always moving. In a solid (like ice) the atoms are moving pretty slowly. In a liquid (like water) they are moving a little faster. In a gas (like steam) the atoms are really moving very quickly; that's why a gas doesn't stick together like a liquid or a solid. Anyway, absolute zero is theoretical, I think. I don't think anyone has actually been able to achieve it yet. It's the point at which the atoms don't move at all, not even tiny vibrations.

Answer 3

Things get hot because the atoms and molecules that they are made of vibrate. The faster they vibrate, the "hotter" they are. Some things vibrate so much that they change from solids, to liquids and when they vibrate even more they become gas. (E.g. Ice, water and steam.)

As the material get cooler, the molecules vibrate less and less. Once the completely stop moving, then they cannot get any colder. This is called "Absolute Zero" and is about 270 degrees Celsius bellow 0 (the melting temperature of ice).

Answer 4

Absolute zero is the coldest that anything can get. It is referred to as absolute zero because it is 0 degrees on the Kelvin scale.
In centigrade it is something like -280 degrees.

Answer 5

Absolute zero is the temperature at which all particles cease motion. Its measured at 0 K.

Answer 6

charle's found out tht volume of a gas is propotional to temp......
the temp at which a gas attains 0 vol is called absolute zero...this is not attainable as a gas can never have zero volume!!!!

Answer 7

absolute zero means that matter can no longer move, basically everything is frozen.

Answer 8

It means the total absence of energy.

Answer 9

Absolute zero is the point on the thermodynamic (absolute) temperature scale where the heat energy is at a minimum, that is, no more heat can be removed from the system.

According to classical physics this temperature would correspond to zero kinetic energy of the particles of the system, in the reference frame of the system's center of mass; this, however, is now known to be false—quantum mechanics explains why the energy of a system can never drop below its zero-point energy.

By international agreement, the Celsius temperature scale starts at absolute zero with the value of exactly -273.15 °C (which approximately agrees with the original definition of the Celsius scale that was based on freezing and boiling point of water). It is approximately -459.67 °F on the Fahrenheit scale. In sciences, where SI units are in use, thermodynamic temperature is measured in kelvins where absolute zero is 0 K. Many engineering fields in the U.S. measure thermodynamic temperature using the Fahrenheit-based Rankine scale where absolute zero is 0 °R.

Scientists have made great advancements in achieving temperatures ever closer to absolute zero (where matter exhibits odd quantum effects). In 1994, NIST achieved a record cold temperature of 700 nK (billionths of a kelvin). In 2003, researchers at MIT eclipsed this with a new record of 450 pK (0.45 nK).

History

The absolute zero state was first proposed by Guillaume Amontons in 1702 who was investigating the relationship between pressure and temperature in gases. He lacked accurate and precise thermometers so his results were only semi-quantitative, but he established that the pressure of a gas increases by roughly one-third between "cold" temperatures and the boiling point of water. His work led him to speculate that a sufficient reduction in temperature would lead to the disappearance of pressure. The problem is that all real gases liquefy during the approach to absolute zero.

In 1848, William Thomson, 1st Baron Kelvin proposed an absolute thermodynamic temperature scale in which equal reduction in measured temperature gave rise to equal reduction in the heat of a body. This freed the concept from the constraints of the gas laws and established absolute zero as the temperature at which no further heat could be removed from a body. Absolute zero has never been reached, and it appears it never will be, although some have come remarkably close. Absolute zero may be asymptotically approached like the speed of light, but never attained. It may be possible that scientists have already reached Absolute Zero, but when the system's temperature is measured, entropy is introduced to the system, thus we may never know for sure.
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Kinetic theory and motion

According to kinetic theory, there should be no movement of individual molecules at absolute zero, so any material at this temperature would be solid. In a monatomic gas, most of the energy is in the form of translational motion, and the temperature can be measured in terms of the distribution of this motion, with slower speeds corresponding to lower temperatures, perhaps even down to absolute zero. But this is contrary to experimental evidence, as helium will never solidify at normal pressures, regardless of temperature.

Because of quantum-mechanical effects, the speed at absolute zero is larger than zero and depends, along with the energy, on the volume within which a particle is confined. At absolute zero, the molecules and atoms in a system are all in their ground state, the state of lowest possible energy, and a system has the least amount of kinetic energy allowed by the laws of physics. But the lowest possible zero-point energy for a confined particle in a box is not zero. Rather than being fixed and non-moving, the equation for the energy levels shows that no matter how low the temperature gets, even when the quantum number takes its minimum value of one, a particle still has some translational kinetic energy and motion. This is a reflection of Heisenberg's uncertainty principle, which states that the position and the momentum of a particle cannot both be known precisely at any given time.

Similarly, using the harmonic approximation for the vibrations of a diatomic molecule, the quantum harmonic oscillator yields a positive zero-point energy even when the vibrational quantum number takes its minimum value of zero. For polyatomic molecules, and for bodies such as crystals, whose normal mode motions can not be assigned to individual atoms or chemical bonds, the lowest-energy state is that of the system as a whole.

Classically, the absolute temperature T of a system of molecules at thermodynamic equilibrium assigns an average of ½ kT to each quadratic kinetic and/or potential energy term in each mechanical degree of freedom, where k is Boltzmann's constant. (See equipartition of energy and the role of the Boltzmann distribution in relating temperature to energy.) But quantum mechanics shows that this is obeyed only for temperatures such that kT > hν, where h is Planck's constant and ν is a characteristic frequency. As T decreases, the assumption that energy is continuously variable fails whenever hν exceeds kT. For vibrational modes in crystals, this happens at room temperature, which explains the deviation of the calculated specific heats of atomic crystals from the experimental Dulong-Petit law value of 3R /mole, a fact which puzzled late 19th century physicists and physical chemists. (Rushbrooke, p. 33)
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Answer 10

No movement in the spatial dimension.