Why is absolute zero important?

1 Answer
Oliver S. · Truong-Son N.
Apr 11, 2018

It is the point at which particle motion stops for monatomic ideal gases. However, molecules will still vibrate.

Explanation:

All temperatures above absolute zero will cause particles in any material to move/vibrate slightly, as temperature gives particles Kinetic energy, according to the equipartition theorem for monatomic ideal gases:

#K_(avg)=3/2k_BT#

#k_B# = Boltzmann's constant = #1.38065 times 10^-23 J//K#
#T# = absolute temperature (Kelvin)

At absolute zero, #T = "0 K"#, so there is effectively no average kinetic energy of the molecules. (although the state of absolute zero is more of a concept as it has not yet been achieved). This means that particle motion ceases in monatomic gases.

Absolute zero is also the foundation for the Kelvin scale, as #"0 K" = -273.15^@ "C"# is the coldest that you can ever hope to get.

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