Today in Science History – March 8 – Otto Hahn

Otto Hahn
Otto Hahn – Father of radiochemistry and discoverer of nuclear fission.

March 8 is Otto Hahn’s birthday. Hahn was a German chemist credited with the discovery of nuclear fission.

Hahn wanted to be an industrial chemist. In order to improve his English language skills, he obtained a position in William Ramsay‘s laboratory. Ramsay taught him how to be a good experimentalist and introduced him to the relatively new field of radioactive elements. Hahn was working with samples of radium when he discovered what he thought was a new element, radiothorium. It would be known later that radiothorium was an isotope of thorium, thorium-228, and not a new element. He continued his studies in Canada under Ernest Rutherford and isolated three other new elements that turned out to be isotopes of known elements: thorium C (polonium-212), radium D (lead-210) and radioactinium (thorium-227).

When he returned to Germany, he began to work with Emil Fischer. He would discover three more element/isotopes: mesothorium I (radium-228), mesothorium II (actinium-228) and ionium (thorium-230). During World War I, he was briefly assigned to work with Fritz Haber to develop chemical weapons for Germany’s war effort before returning to radiochemistry and his partnership with Lise Meitner. The two of them would finally isolate their first genuine element which they called proto-actinium. Today, the name is shortened to protactinium.

Hahn and Meitner had a long-lasting work relationship. The pair worked together until the rise of the Nazi party caused Meitner to flee to Stockholm. Hahn helped her leave and gave her his mother’s diamond ring to use as a bribe if necessary. They corresponded through Hahn’s assistant, Fritz Strassmann. One set of projects they were working on was bombarding uranium with neutrons to try and produce transuranic elements. Strassmann wrote to Meitner that he had been identifying barium among the samples of uranium. Barium is nearly half the atomic weight of uranium and Hahn felt that it was possible the uranium nucleus had ‘burst’ somehow. Meitner and her nephew Otto Frisch calculated it was possible for a uranium nucleus to split or ‘fission’ when hit by a neutron. Hahn would win the 1944 Nobel Prize in Chemistry for the discovery of nuclear fission.

Hahn spent World War II working on fission reactions where he identified 25 elements and 100 different isotopes. While he did not work on any German atomic weapon program, he and nine other German scientists were captured in July of 1945. He was interned at Farm Hall, England where he learned he won the Nobel Prize through an English newspaper.

After the war, Hahn was instrumental in rebuilding German science. He served as the president of the newly formed Max Planck Society. He became a spokesman against the weaponization of atomic fission, nuclear weapons, and other misuses of nuclear energy.

Some consider Hahn to be the father of radiochemistry. His book Applied Radiochemistry was the standard handbook for anyone working in the field in the 1930s-40s.

Notable Science History Events for March 8

2005 – César Lattes died.

Lattes was a Brazilian physicist who discovered the pi meson particle with Eugene Gardener. Pi mesons or pions are composed of a quark and antiquark to from lightweight mesons. They have a significant role in explaining the strong nuclear force.

1979 – Voyager 1 discovers volcanos on Io.

Io Volcano Mosaic
Mosaic of images of Io’s South Pole showing several volcanoes.

NASA’s space probe, Voyager I sends back photographs showing active volcanoes on Jupiter’s moon Io. This discovery would be confirmed during Voyager 2’s Io flyby on July 9, 1979.

Comparisons between the two flybys would show Io to have an extremely active geology.

1924 – Georges Charpak was born.

Georges Charpak
Georges Charpak (1924 -2010) Credit: Studio Harcourt/Creative Commons

Charpak is a Polish-French physicist who was awarded the 1992 Nobel Prize in Physics for his invention of the multiwire proportional chamber and other particle detectors. A multiwire proportional chamber uses an array of high voltage wires in a chamber of ionizing gas. When a charged particle enters the chamber, it will ionize the gas and cause a current change in the wires near the particle’s path. Measuring the current and determining which wire is supplying the current gives information on the position, path, charge, and energy of the ionizing particle.

1923 – Johannes Diderik van der Waals died.

Johannes Diderik van der Waals
Johannes Diderik van der Waals (1837 – 1923)

Johannes Diderik van der Waals was a Dutch physical chemist who was awarded the 1910 Nobel Prize in Physics for describing a state of matter where the liquid and gas phases merge together continuously. He was the first to postulate an intermolecular force. He also derived a general equation for the ideal gas equation taking into account the attractive forces and volumes of the molecules.

1886 – Edward Calvin Kendall was born.

Edward Calvin Kendall
Edward Calvin Kendall (1886 – 1972) Nobel Foundation

Kendal was an American chemist who discovered the hormone cortisone. He also shares the 1950 Nobel Prize in Medicine with Tadeus Reichstein and Philip Hench for their research on the structure and effects of adrenal cortex hormones. He independently discovered the adrenal hormone cortisone and isolated the thyroid hormone thyroxine and determined its structure.

1879 – Otto Hahn was born.

1866 – Pyotr Nikolayevich Lebedev was born.

Pyotr Nikolaevich Lebedev
Pyotr Nikolaevich Lebedev (1886 – 1912)

Lebedev was a Russian physicist who was the first to prove light exerts mechanical pressure on a surface it is shined on. He accurately measured the pressure of light on a solid body which gave the first quantitative proof to Clark Maxwell’s electromagnetic theories. He was responsible for the popularization of physics to a generation of Russian scientists.

1836 – Michael Foster was born.

Michael Foster
Michael Foster (1836 – 1907)

Foster was an English physiologist who introduced modern methods of teaching biology that emphasize training in the laboratory. His methods would put Britain at the forefront of physiological studies and research and make physiology a scientific profession.

1822 – Jan Józef Ignacy Lukasiewicz was born.

Ignacy Łukasiewicz (1822 – 1882)

Lukasiewicz was a Polish pharmacist who discovered a method to extract kerosene from seep oil and the invention of the kerosene lamp. He is credited with the construction of the world’s first oil refinery facility and Poland’s first oil well.

1717 – Abraham Darby died.

Darby was an English ironmonger who invented the process of coke smelting for producing iron from ore. Before this, iron was smelted with charcoal. Darby’s method produced a much higher quality of iron and greatly decreased the costs associated with production. Darby is considered one of the pioneers of the Industrial Age for this discovery.