2. What's in a name? At the crossroads between chemistry and physics

In the 1700's, a dramatic paradigm shift was brewing in the chemical sciences. Until then, chemistry had been part art and part taxonomy. The question was whether one could make sense of it all based on fundamental principles about the substances themselves. (We didn't quite yet know that substances were made of tiny building blocks, namely atoms.) Or to put it bluntly, is there an underlying physics to chemistry? Thus physical chemistry (or is it chemical physics?) was born as an interdisciplinary science. It's now a part of the core of the discipline of chemistry. It is also a popular node in the web science in which the interdisciplinary sciences act as the links.

The interdisciplinary field lying between chemistry and physics took hold in the late 19th century. Ostwald recognized the power of the new physics of the day—thermodynamics—to help make sense of the energetics or molecular motions and reactions. Thus was born the field of physical chemistry, and the eponymous journal within the American Chemical Society. The trouble is that when new physics—such as quantum mechanics—came along, the editor of the Journal of Physical Chemistry at the time wasn't ready to accept it. This led to the rather odd definition of physical chemistry as being limited to the thermodynamics of chemical processes. This, in turn, necessitated the definition of a new interdisciplinary field, chemical physics, which included the use of all physics (even thermodynamics) to understand chemical processes. As the corresponding eponymous journal was subsumed under the umbrella of the American Institute of Physics, some chemists (though not most) did not make the jump to chemical physics. This, in turn, led the Journal of Physical Chemistry to focus on topics in the middle of the 20th century with decreasing relevance. (Fortunately this misdirection did not persist, and the happy ending is coming soon!) Meanwhile, the name confusion continues to recur as students routinely ask me what exactly is the difference between chemical physics and physical chemistry today. My answer to the question follows in the posts to come!

(Note that this is the second post in a series. Click here for the previous post.)