National Physical Laboratory Video Presentations on Temperature Measurements


New references for high temperature measurements

As a culmination of an eight-year research programme an international collaboration has developed robust reference fixed points, studied their sensitivity to impurities and external conditions and finally measured their melting transition temperature.
This talk describes how 100+ measurements made by nine different NMIs have been combined to assign low-uncertainty thermodynamic temperatures to the melting transition of Re-C, Pt-C and Co-C metal-carbon eutectics.
At the simplest level, these fixed-points will provide new temperature references for the calibration of pyrometers at temperatures above the freezing point of silver (1234.93 K) and will thus reduce the uncertainties associated with high temperature measurement compared to those achievable using the International Temperature Scale of 1990 (ITS-90).
The thermodynamic temperatures of these fixed-points have been determined through direct measurement of the radiance of a blackbody cavity surrounded by the fixed-point material from Planck’s law and hence the Boltzmann Constant. The evolving mise en pratique for the definition of the kelvin encourages the realisation and dissemination of thermodynamic temperature.
This may be directly – and the work described in this talk shows that filter radiometry is sufficiently mature for this, or it may be by providing fixed-points with reference thermodynamic temperatures that have associated uncertainties – and this talk will outline such temperatures.
Innovations in High Temperature Measurement
A 49 minute review of the present technical status of High Temperature measurement by one of the leaders in temperature Metrology at NPL in the UK.

Presented by Dr. Graham Machin, NPL (Recorded July 2011)
Recent and unfolding innovations in this area promise step change improvements throughout the measurement chain; from realisation of temperature above 1300 K in National Measurement Institutes, dissemination of the scale to calibration laboratories, down to the practice of industrial high temperature thermometry.
More details:

New references for high temperature measurements

Summary of work reported for high temperature measurements from NPL As a culmination of an eight-year research programme an international collaboration has developed robust reference fixed points, studied their sensitivity to impurities and external conditions and finally measured their melting…

Temperature Calibration & Metrology Web Seminar Archives

Fluke Calibration’s Focus on Basics – RTDs – Digital & IR (Infrared Radiation) Thermometers Online —  Fluke Calibration’s free online web seminars cover a wide range of calibration and temperature topics. More are scheduled monthly. To learn about upcoming events,…

Temperature Measurement – Lecture 9

“The Science & Art of Temperature Measurement”

The first Lecture in Module 2, on the first topic of the Mechanical Measurements and Metrology, a part of the course from the Indian Institute of Technology Madras, India – online at
It assumes an educational level of at least first year college engineering or higher, Some of the topics in this series of lectures also assume some knowledge of prior lectures in the Series (see below).

This is but one of the 50 videos in this course. A full list of the course contents is below.
The courses related to temperature measurement in this series are Numbers 9 through 19, inclusive, titles illustrated in red below. Additional lectures in this course detail related topics in measurement errors, and measurements of thermophysical properties of matter, subects that any serious student of temperature measurement should know well, indeed. The tiles of the latter lecture topics are shown as green in the list.
All of these lectures may be seen here or on, or on the NPTEL website at, where flowplayer is used to display the lectures.

Calibrating Ordinary Thermometers

This six-minute video by AquaLab captures the correct way to check, verify and if necessary, adjust some ordinary thermometers using an ice bath.
Most people think that it’s easier to do so at the boiling point of water, but the ice point (very nearly 0.01 ° C at all normal atmospheric pressures) is far more stable than the boiling point that varies considerably with atmospheric pressure and consequently the altitude of the location at which the measurement is made.

What’s more, the ice point was, until about 1990, the fundamental reference point for the Centigrade and Fahrenheit scales. However, when the internationally agreed definition of the Celsius scale replaced the Centigrade scale, as a part of The International Temperature Scale (ITS-90) .
The new reference became the triple point of water precisely 0.01 ° C lower than the ice point. The ice point of water, a well-stirred mixture of ice and water is still as stable as ever, for ice and water that are free of contaminants (that is, both made up of distilled, de-ionized water).

Temperature (T)-Bob Abel on YouTube

Dr. Bob Abel of Olympic College in Bremerton, Washington (USA) has a series of YouTube videos that we think are very well done. His low-key and sometimes humorous approach to the basics of science and temperature, as concepts, and how some temperature sensors work, are some of the cleverest and most viewer-friendly ones we’ve seen to date.
Below are his two brief presentations on temperature and scale/unit conversions in lumps of about 5 to 7 minutes each. There are many more at