A sound idea to redefine temperature


UK scientists want to redefine temperature using the Boltzmann constant, changing the way in which it has been calculated for over 50 years. The group, working at the UK’s National Physical Laboratory, published a study today that could make it possible to measure temperature much more accurately in the future.

The current definition of temperature relies upon the triple point of water – the state at which water can be ice, liquid and vapour in equilibrium – but this makes accurate measurements of extreme temperatures difficult. The team say that the solution is to link the standard unit of temperature, the kelvin, to the Boltzmann constant, a measure of the relationship between kinetic energy and temperature. By making precise measurements of the speed of sound in argon gas the team could gauge the average speed of the gas molecules and therefore their kinetic energy. From this they were then able to calculate the Boltzmann constant

‘It is fascinating that we worked out how to measure temperature long before we knew what temperature actually was. Now we understand that the temperature of an object is related to the energy of motion of its constituent atoms and molecules,’ says lead author Michael de Podesta. ‘The new definition directly links the unit of temperature to this basic physical reality.’


Related Content

Wedgwood’s pyrometer

19 December 2012 Classic Kit

news image

Taming the fiery heat of kiln and furnace

Chemistry World podcast - February 2013

4 February 2013 Podcast | Monthly

news image

Graham Richards discusses crowdsourcing, Eric Wolff talks about ice cores and the team cover the latest chemical news

Most Commented

Lithium–sulfur batteries ready to go the distance

3 December 2013 Research

news image

Innovative electrodes set to put electric cars in the fast lane with a new design that holds double the energy of ordinary li...

Graphene made in a kitchen blender

22 April 2014 Research

news image

High quality flakes of two-dimensional material exfoliated from graphite points way to bulk production