Frontiers of Knowledge

National Historic Chemical Landmarks Program

Some 2,500 years ago, the Greek philosopher Aristotle postulated that all matter is comprised of four basic elements: earth, water, air, and fire. The idea dominated science until the late 18th century, when revolutionaries from rival nations transformed chemistry from a jumble of medieval alchemy into a true science. The pace of discovery accelerated rapidly as chemists on the frontiers of knowledge established the theories and methodologies of modern science.

Antoine-Laurent Lavoisier: The Chemical Revolution

Antoine-Laurent Lavoisier forever changed the practice and concepts of chemistry by forging a new series of laboratory analyses that would bring order to the chaotic centuries of Greek philosophy and medieval alchemy. Through his influential work, Lavoisier challenged the prevailing “phlogistic” theory and demonstrated the true role of oxygen in combustion; he described the role of oxygen in respiration, and showed that water is not an element but a compound comprised of hydrogen and oxygen. Lavoisier’s work in framing the principles of modern chemistry led future generations to regard him as a founder of the science. Learn more.

C.V. Raman: The Raman Effect

The discovery that earned C. V. Raman the 1930 Nobel Prize in physics was born of an investigation of light sparked by a question a child might ask. Returning to his native India by way of the Mediterranean Sea, Raman wondered about the sea's deep blue color. Dissatisfied with the prevailing explanation—that it reflected the sky—he delved further and demonstrated a universal truth about the behavior of light. In 1928, Raman discovered that when a beam of colored light enters a liquid, it scatters and some of it emerges as a different color. This deceptively simple observation had profound implications. Learn more.

Deciphering the Genetic Code

Interpreting the language of the genetic code was the work of Marshall Nirenberg and his colleagues at the National Institutes of Health. Their careful work, conducted in the 1960s, revealed the first word of the genetic code. In the next few years, Nirenberg’s laboratory discovered the codes for all possible combinations of the twenty amino acids. Nirenberg’s work helped pave the way for the mapping of the human genome and for much of recent understanding of the correlations of genetics and disease. Learn more.

Discovery of Fullerenes

In 1985 Richard Smalley and Robert Curl of Rice University and Harry Kroto of the University of Sussex discovered the first known molecular form of carbon, C60, also known as fullerenes, or buckyballs. Research on fullerenes has led to the synthesis of more than one thousand new compounds, and to advances in the development of carbon nanotubes, which have uses in tiny motors and as ball bearings and lubricants. Fullerenes continue to provide abundant research opportunities in pure chemistry, materials science, pharmaceutical chemistry, and nanotechnology. Learn more.

Edward W. Morley and the Atomic Weight of Oxygen

In his laboratory at Western Reserve University (Now Case Western Reserve University), Edward W. Morley carried out his research on the atomic weight of oxygen that provided an important new standard to the science of chemistry. His analytical techniques earned him national renown, and the accuracy of his analyses has never been superseded by chemical means. His great work, published in 1895, also gave important insight into the atomic theory of matter. Learn more.

Foundations of Polymer Science: Hermann Staudinger and Macromolecules

Early 20th century chemists believed that the remarkable physical properties of materials like rubber and cellulose were the result of small molecules aggregated into large units by forces weaker than chemical bonds. In 1920, Hermann Staudinger published a paper challenging that view. He postulated that rubber and similar materials are composed of very large molecules that are held together by chemical bonds—the same forces that hold smaller, lighter molecules together. Hermann Staudinger’s pioneering theories on the polymer structures of fibers and plastics and his later research on biological macromolecules formed the basis for countless modern developments in the fields of materials science and biosciences and supported the rapid growth of the plastics industry. Learn more.

Joseph Priestley: Discoverer of Oxygen

When Joseph Priestley discovered oxygen in 1774, he answered age-old questions of why and how things burn. He accurately documented its properties but explained what he observed in terms of then-prevailing theory, which held that when things burned they lost "phlogiston," an inflammable substance. An Englishman by birth, Priestley was deeply involved in politics and religion, as well as science. When his vocal support for the American and French revolutions made remaining in his homeland dangerous, Priestley left England in 1794 and continued his work investigating gases in in Northumberland, Pennsylvania. Learn more.

Moses Gomberg and Organic Free Radicals

In 1900, University of Michigan chemist Moses Gomberg achieved what chemists had long believed impossible: He isolated an organic free radical (a carbon compound with an unpaired electron). The accomplishment paved the way for development of polyethylene, Plexiglas®, and other polymers used by the plastics industry. Gomberg's discovery also advanced biochemistry, biology and medicine. Organic free radicals are crucial to our understanding of many natural phenomena, including how our bodies synthesize DNA and why some oxidative processes support life while others cause disease. Learn more.

Neil Bartlett and the Reactive Noble Gases

Science is frequently a collaborative discipline. But sometimes, one person, working alone, makes a stunning discovery that changes a scientific field forever. Neil Bartlett, while working alone in his laboratory, demonstrated that the "inertness" of the Group VIII elements was not a fundamental law of nature as previously believed. Bartlett's discovery meant that all existing textbooks had to be rewritten. Today, compounds of the noble gases are used in a variety of applications, including in lasers and to create anti-tumor agents. Learn more.

NMR and MRI: Applications in Chemistry and Medicine

MRI (magnetic resonance imaging) has become a staple of medical diagnostics: MRI is a useful non-invasive and non-destructive diagnostic tool for imaging soft tissues such as the brain, heart and muscles, and for discovering tumors in many organs. MRI is an application of NMR (nuclear magnetic resonance), an analytical tool of chemists found in laboratories worldwide. Together, NMR and MRI revolutionized the practice of chemistry and medicine by providing fast, non-destructive, and non-invasive means for the observation of matter from the atomic to the macroscopic scale. Learn more.

Production and Distribution of Radioisotopes at Oak Ridge National Laboratory

Conceived in wartime, Oak Ridge National Laboratory (ORNL) managed the transition to peacetime, in part, through the production and distribution of radioisotopes, perhaps the most important scientific byproduct of the Manhattan Project. These radioactive forms of chemical elements have a myriad of medical, industrial, and agricultural uses. The availability of radioisotopes led to advances in chemistry, biochemistry, molecular biology, and many other applied and theoretical sciences. Learn more.

Separation of Rare Earth Elements by Charles James

Charles James, a chemistry professor at the University of New Hampshire from 1906 to 1928, was an internationally-recognized expert in rare earth chemistry. In a laboratory in Conant Hall, James devised novel fractional crystallization techniques for separating rare earth elements, which were widely adopted by other chemists. James used his method to separate large amounts of ytterbium, previously considered to be a single element, into two elements now known as ytterbium and lutetium. Learn more.