Kelvin Temperature Scale

Howsare: So you think it's hot?

THIRD ROCK FROM THE SUN — With daytime highs sometimes exceeding 110 degrees, maybe you think it's almost too hot in Maricopa to sustain human life.

Forget about it.

The hottest summer on record in Arizona — or any other place on the planet for that matter — is still as cool as a cucumber compared to temperatures on the surface of the sun.

This odd-looking picture of the sun was taken Saturday by the Extreme Ultraviolet Imaging Telescope on board the Solar and Heliospheric Observatory (SOHO) spacecraft. The unmanned spacecraft was launched in December 1995 as a cooperative project of the European Space Agency and NASA. So how hot is 2 million degrees Kelvin? The Kelvin scale is an international standard for scientific temperature measure. Zero degrees Kelvin is equal to absolute zero, the theoretical temperature at which all atoms and molecules have the least possible energy. In layman’s terms, absolute zero is the temperature at which all known matter in the universe would become literally frozen solid. Hard as a rock. Dead as a doornail.

But as Star Trek’s know-it-all Science Officer Spock might pontificate: “Absolute zero exists only in theory, Captain.” No one has ever encountered or observed such an event. We’d probably all be dead if someone did. (The irascible Dr. McCoy would be saying “He’s dead, Jim!” more times than any of us could count.)

The Kelvin scale is related to the Celsius scale — a measurement frequently used by scientists in which “0” is the point at which water freezes and “100” is the temperature at which water boils. One Kelvin unit is equal to one Celsius unit.

A Kelvin temperature can be obtained by adding 273.15 to any Celsius temperature. Measured by the Celsius scale, absolute zero is minus 273.15 degrees Celsius. Converted to the Fahrenheit scale, which we use every day to determine the temperatures of our physical environment, 2,000,273.15 degrees Celsius becomes nearly 3.6 million degrees Fahrenheit. (There’s a complicated math equation to do this, but just use the Kelvin to Fahrenheit converter at www.easysurf.cc/cnver14.htm#kf2)

And that’s way hotter than it ever gets here in the desert! For more information about the SOHO exploration, visit http://sohowww.nascom.nasa.gov/

Tim Howsare is senior reporter at InMaricopa.com.

Dead Scientist of the Week: William Thompson, Baron Kelvin

From Latin into English. His first scientific paper was published in 1841 and in that year he entered St. Peter's College, Cambridge to read for the mathematical tripos. During his time at Cambridge he rowed for his college and remained involved in nautical pursuits throughout his life. He graduated in 1845, second wrangler (the university examiner commented that the Senior Wrangler "was not fit to cut pencils for Thompson") and winning first place in the Smith's Prize competition. He was elected fellow, shortly thereafter. At the time experimental physics was not taking place at Cambridge, so after graduation he took his fellowship to Paris, and he worked in the laboratory of Henri Regnault for a year, where he determined data on a number of physical constants. In 1846 the chair of natural philosophy at Glasgow University became vacant and Thompson was elected. He remained in the position for fifty-three years until his retirement in 1899, despite many invitations to leave and go elsewhere. He was an inexhaustible worker, producing almost six hundred papers, seventy patents, as well as a number of books during his tenure. Thompson is most famous for his work on an absolute zero temperature, a temperature at which entropy is reduced to its lowest possible value. The Kelvin temperature scale, named after Thompson, has its zero at -273.15 degrees Celsius or -459.67 degrees Fahrenheit. At this temperature nearly all molecular motion stops and pure substance form perfect crystals. It is not possible to reach absolute zero artificially, but there are techniques to get within a billionth of a degree using cooling lasers. Thompson served as the electrical engineer during the laying of the first successful Transatlantic Telegraph Cable and was knighted for his services. He was elected to the Royal Society in 1851 and won the Copley Medal in 1883. His title, Barron Kelvin, bestowed on him in 1892, origninated from the River Kelvin which runs through the grounds of the University of Glasgow and he is the first scientist who served in the House of Lords. When I was taking freshman chemistry lab my instructor, Dr. Harry Press, included a lesson in science history in his weekly lectures on our experiments. I found this method of teaching, including a history lesson with the scientific material fascinating and helpful making the material more accessible.

General, Organic, and Biochemistry, An Applied Approach

In Quest of the Solar System

Fundamentals of Engineering Thermodynamics

Physics

Physics for scientists and engineers