Interesting online CONFCHEM discussion going on right now on the ChemWiki and
greater STEMWiki Hyperlibary project. Come join the discussion.

ChemWiki: The Dynamic Chemistry Hypertext > Under Construction > Demonstrations > Additional Demos > The Determination of Absolute Zero

The Determination of Absolute Zero

Chemical Concepts Demonstrated

  • Absolute zero
  • Pressure/temperature relationship in gases


  • Attach the pressure gauge on the Boyle's law apparatus to a metal sphere.
  • Immerse the sphere in one of the different temperature baths: hot, warm, room temp., ice, and slush; and record the temperature of the bath and pressure of the gas within the sphere.
  • Plot these on a temperature vs. pressure line graph.


The lower the temperature, the lower the pressure inside of the sphere.  If the exact values were plotted out, a linear relationship would be apparent.   Extrapolating this line to the point where there would be no pressure yields absolute zero, which is about -273.15 degrees Celsius.


Pressure is caused by the collisions of gas particles with each other and whatever objects they may collide with.  When the temperature is lowered, the particles move more slowly, decreasing the frequency and strength of these collisions.   In turn, the pressure falls.

Absolute zero can be defined as the temperature at which matter does not move.  At absolute zero, even subatomic vibrations are put to a grinding halt.  Because the pressure in this experiment is caused by the movement of a gas, the pressure would cease to exist when the gas stops moving (a.k.a. absolute zero).  Therefore, when the linear relationship discovered in this experiment is extrapolated to the point where the pressure is zero, the corresponding temperature is absolute zero.



You must to post a comment.
Last modified
10:30, 2 Oct 2013



(not set)
(not set)

Creative Commons License Unless otherwise noted, content in the UC Davis ChemWiki is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License. Permissions beyond the scope of this license may be available at Questions and concerns can be directed toward Prof. Delmar Larsen (, Founder and Director. Terms of Use