Volume 1, Issue 3
Berkeley's Scientific Legacy
1933: William F. Giauque and the quest for absolute zero
How cold can cold get? Absolute zero, of course. But how cold is that? Beginning in the mid-18th century with Gabriel Daniel Fahrenheit's temperature experiments, scientists sought to demonstrate the theoretical temperature at which all molecular motion would stand still.
By the early 20th century, the magic number of 459.688 degrees below zero on the Fahrenheit scale (-273.15 C) was agreed upon to be absolute zero. Until 1933 though, the coldest temperature reached was 458 degrees below zero. Many scientists doubted it was possible to go any lower.
William F. Giauque (1895-1982) received his BS in Chemistry in 1920 and his PhD in 1922 from the UC Berkeley College of Chemistry.
UC Berkeley chemist William F. Giauque wasn't convinced though. During his graduate studies at Berkeley, Giauque immersed himself in low-temperature work, a line of research he continued when joining the chemistry faculty in 1922. Five years later, he proposed a new magnetic refrigeration method to achieve extremely low temperature. The process, called adiabatic demagnetization and still used today, involves removing the magnetic field from certain materials. In 1929 through low-temperature studies of oxygen, Giauque and collaborator H.L. Johnston discovered the oxygen isotopes of mass 17 and 18. But Giauque's inquiries into entropy drove him even further.
One day in 1933, after working 21 straight hours on a key experiment, Giauque made his breakthrough observation. His machine had achieved a temperature within one-tenth of a degree of absolute zero. (The current record low, hit last year, is one-half-billionth of a degree Fahrenheit above absolute zero.) Giauque's experiments confirmed the third law of thermodynamics, which states that the entropy of a pure perfect crystal is zero at absolute zero--the atoms are perfectly aligned and don't move. In 1949, he received the Nobel Prize in Chemistry for opening new vistas for chemists and physicists to study the very essence of matter.
Upon presentation of the award, a Nobel Committee member introducing Giauque said, "In order to extend our knowledge of those laws in Nature which determine the properties of matter and its transformations, it has been necessary to penetrate into the field of the lowest temperatures ever reached by man. You have created methods necessary for accurate measurements under these extreme conditions, and you have applied these methods to a precise study of previously unknown phenomena which are of the deepest significance for science. Your results have afforded the final proof of one of the most fundamental laws in Nature, a law which is also of immense practical importance."
Giauque died in 1982 but his legacy lives on at UC Berkeley's Giauque Hall, home to the University's Low Temperature Laboratory, and across all of physical science.