Featured Research

from universities, journals, and other organizations

UF Researcher's Work To Result In New, Lower Temperature Scale

Date:
February 22, 2000
Source:
University Of Florida
Summary:
The blue numbers on the thermometer are about to extend to a new low, thanks to the work of a University of Florida researcher.

Writer: Aaron Hoover

Source: Dwight Adams, (352) 392-0485, adams@phys.ufl.edu

GAINESVILLE, Fla. --- The blue numbers on the thermometer are about to extend to a new low, thanks to the work of a University of Florida researcher.

A temperature scale pioneered by UF physics Professor Dwight Adams soon will become the world's official standard for measuring the coldest temperatures known to man -- temperatures just shy of absolute zero, or minus 459.67 degrees Fahrenheit.

Such temperatures are so extreme they do not occur naturally anywhere in the universe, not even in the empty space between galaxies. But physicists and chemists create the lows in laboratories because they shed light on the nature of matter and may turn materials into superconductors, superfluids or prompt them to undergo other unique changes. Now, an international committee of physicists is set to adopt Adams' technique for measuring ultracold temperatures as the world standard to ensure scientists accurately measure and compare results no matter where they work.

"The importance of this is that researchers in Europe and the U.S. will all have the same temperature scale," said Marten Durieux, a physicist at the University of Leiden in the Netherlands and one of the officials in charge of adopting the new scale.

The world's current official temperature scale, the International Temperature Scale of 1990 (ITS-90), has a lower limit of 0.65 Kelvin, or minus 458.5 degrees Fahrenheit. When adopted later this year, the new scale will drop to 0.001 Kelvin, or minus 459.66 degrees.

Such temperatures had been out of reach to all but the most specialized laboratories in the world until the past two decades, when refrigerators that could lower temperatures to 0.01 Kelvin became commercially available. The result has been an explosion of research in this low temperature range, increasing the need for the new scale, Adams said.

"There's lots of work going on in this range now, and there is no defined scale for the people doing it, so this will be quite useful to them," he said.

Adams and two graduate students, Gerald Straty and Richard Scribner, laid the groundwork for the scale 35 years ago when they found a way to measure ultra cold temperatures using an isotope called helium-3.

When subjected to the extreme temperatures below 1 Kelvin, or 457.7 Fahrenheit, most materials freeze solid, Adams said. Helium, by contrast, remains a liquid all the way to absolute zero. When different pressures are applied to helium-3 at very low temperatures, however, it transforms into a changing mix of solid and liquid. The pressure at which it makes that change is known as the isotope's "melting pressure." If the melting pressure can be measured accurately, the scale can be calibrated.

To achieve that, Adams and Straty invented a measuring device known as the Straty-Adams gauge. Smaller than a Matchbox car, the gauge fits inside the inner chamber of a cryostat, the liquid nitrogen and helium refrigerator used to create ultralow temperatures. As the temperature drops and some of the helium-3 transforms from one state to another, the corresponding change in the melting pressure causes the diaphragm in the device to move slightly. Although the amount of movement is very small, totaling less than one-thousandth of an inch, it can be translated into temperature change via an equation.

Physicists have been using the gauge since Adams, Straty and Scribner pioneered it, but scientists disagreed about proper calibration of the scale. Two standards laboratories, the National Institutes of Standards and Technology, or NIST, in the United States and the Physikalisch-Techische Bundesanstalt in Germany, each proposed their own scale. Meanwhile, Adams and two UF colleagues, graduate student Win Ni and research scientist Jian-Sheng Xia, proposed a third scale. At a meeting at NIST's Maryland headquarters in January, however, the three parties came together and agreed to one new scale.

Durieux, the University of Leiden physicist, is a member of a working group that is part of the International Committee of Weights and Measures, which governs temperature and weight measurements worldwide.

He said the group will recommend at a meeting in April that the full committee approve the new temperature scale, ITS-2000, at its next meeting in Paris in September. He said he is confident the full committee will approve the recommendation.


Story Source:

The above story is based on materials provided by University Of Florida. Note: Materials may be edited for content and length.


Cite This Page:

University Of Florida. "UF Researcher's Work To Result In New, Lower Temperature Scale." ScienceDaily. ScienceDaily, 22 February 2000. <www.sciencedaily.com/releases/2000/02/000218112430.htm>.
University Of Florida. (2000, February 22). UF Researcher's Work To Result In New, Lower Temperature Scale. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2000/02/000218112430.htm
University Of Florida. "UF Researcher's Work To Result In New, Lower Temperature Scale." ScienceDaily. www.sciencedaily.com/releases/2000/02/000218112430.htm (accessed September 18, 2014).

Share This



More Matter & Energy News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Newsy (Sep. 18, 2014) Apple's new operating system, iOS 8, comes with Apple's killswitch feature already activated, unlike all the models before it. Video provided by Newsy
Powered by NewsLook.com
Stocks Hit All-Time High as Fed Holds Steady

Stocks Hit All-Time High as Fed Holds Steady

AP (Sep. 17, 2014) The Federal Reserve signaled Wednesday that it plans to keep a key interest rate at a record low because a broad range of U.S. economic measures remain subpar. Stocks hit an all-time high on the news. (Sept. 17) Video provided by AP
Powered by NewsLook.com
Space Race Pits Bezos Vs Musk

Space Race Pits Bezos Vs Musk

Reuters - Business Video Online (Sep. 16, 2014) Amazon CEO Jeff Bezos' startup will team up with Boeing and Lockheed to develop rocket engines as Elon Musk races to have his rockets certified. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins