Today in Science History – February 1 – Emilio Segrè

Emilio Segrè

Emilio Segrè (1905 – 1989)
Nobel Foundation

February 1 is Emilio Segrè’s birthday. Segré was an Italian physicist who discovered the first artificial element.

Segrè was visiting the University of California Berkeley’s radiation laboratory and met with Ernest Lawrence. Lawrence was the man who designed the first cyclotron particle accelerator. Segrè was interested in some of the discarded material from the cyclotron that had become radioactive through the operation of the device. He asked Lawrence if he could take the materials back to Italy to study and received a sheet of molybdenum foil.

Back in Italy, Segrè and his partner Carlo Perrier isolated a small amount of something giving off gamma radiation not attributed to molybdenum. They identified this sample as the long-sought element 43 missing from Mendeleev’s list of unknown elements. Segrè returned to California and met with Glenn Seaborg to see if they could create more of their element. They bombed molybdenum with deuterons from the cyclotron and produced more element 43. His new element was called technetium after the Greek word for artificial since it was produced artificially.

Segrè also discovered another radioactive element: astatine. Astatine was another missing placeholder element on Mendeleev’s periodic table called eka-iodine. Like technetium, there had been several claims of discovery for eka-iodine, but there were difficulties reproducing these claims. Segrè and a team at the Berkeley cyclotron created their astatine by bombarding bismuth-209 with alpha particles. They named their discovery after the Greek word astatos meaning ‘unstable’ with the -ine suffix since it appeared in the halogens column of the periodic table.

If discovering two elements weren’t enough, Segrè also co-discovered the antiproton with Owen Chamberlain. The antiproton is a proton with a negative charge, much like the positron is an electron with a positive charge. Its existence was predicted by Paul Dirac in 1933, but the energy needed to produce them was not available. Berkeley’s new bevatron particle accelerator could accelerate particles to the needed energy. They produced their first antiprotons in 1955. The discovery of the antiproton would earn both men the 1959 Nobel Prize in Physics.

Notable Science History Events for February 1

2003 – Space Shuttle Columbia destroyed during re-entry.

Crew of STS-107

Crew of STS-107

The Space Shuttle Columbia was destroyed during re-entry into the Earth’s atmosphere killing all seven astronauts aboard. The shuttle was damaged by a piece of foam insulation from the main propellant tank during lift-off. The foam damaged the heat-resistant tiles that protect the shuttle from the heat of re-entry.

1976 – George Hoyt Whipple died.

George Whipple (1878 - 1976)

George Whipple (1878 – 1976)
Nobel Foundation

Whipple was an American physician who shares the 1934 Noble Prize in Medicine with George Minot and William Murphy for their work on the treatment of anemia. Whipple showed that anemic dogs who were fed liver improved their condition, actually reversing the condition.

This discovery would lead to the successful treatment of pernicious anemia by Minot and Murphy.

1976 – Werner Heisenberg died.

Werner Heisenberg

Werner Heisenberg (1901 – 1976)

Heisenberg was a German physicist who Heisenberg is best known for his uncertainty principle where the position of a particle and its momentum cannot be precisely determined. He was also awarded the 1932 Nobel Prize in Physics for the creation of the study of quantum mechanics.

1972 – First hand-held scientific calculator introduced.


Hewlett Packard’s HP-35, the first handheld electronic scientific calculator. Hewlett Packard Museum

The first hand-held, electronic scientific calculator was introduced by Hewlett Packard.

Electronic calculators were first introduced as accounting machines with the basic four functions of addition, subtraction, multiplication, and division. Scientists needed a little more functionality than this. Hewlett-Packard released the HP-35 calculator to fit this need. It could perform complex trigonometrical, exponential, and logarithmic functions with a single press of a button.

1958 – Clinton Joseph Davisson died.

Clinton Davisson

Clinton Davisson (1881 – 1958)
Nobel Foundation

Davisson was an American physicist who shares the 1937 Nobel Prize in Physics with George Thomson for their independent discovery that electrons could be diffracted like light waves. This suggested particles could have wave properties, confirming the theory of de Broglie and is a basis of quantum mechanics.

1952 – Roger Yonchien Tsien was born.

jellyfish luminescence

Aequorea victoria jellyfish. Sierra Blakely

Tsien is a Chinese American biochemist who shares the 2008 Nobel Prize in Chemistry with Osamu Shimomura and Martin Chalfie for their discovery of the green fluorescent protein. The green fluorescent protein is a protein that glows bright green in the presence of blue light and found in Aequorea victoria jellyfish.

1944 – DNA identified as the hereditary agent in a virus.

Oswald Avery, Colin MacLeod, and Maclyn McCarty announced that DNA was the hereditary agent in a virus that would transform a virus from a harmless to a pathogenic version. This study was a key work in modern bacteriology.

1905 – Emilio Segré was born.

1903 – George Stokes died.

George Stokes (1819–1903)

George Stokes (1819–1903)

Stokes was an Irish physicist who is known for his law of viscosity involving the speed of a sphere falling in a liquid and other principles of fluid dynamics.

He also described fluorescence as a change in wavelength from ultraviolet to visible. This shift in energy would be called the Stokes shift in his honor.

1885 – Sidney Gilchrist Thomas died.

Sidney Gilchrist Thomas

Sidney Gilchrist Thomas (1850 – 1885)

Thomas was a British metallurgist who developed a process to remove phosphorus impurities from iron ores to improve the strength of steel. He added burned limestone to the mixture to increase the alkalinity. The phosphorus would attach itself to the calcium in the form of calcium phosphate (Ca3(PO4)2). The calcium phosphate would accumulate in the slag waste products.

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