October 19 marks the passing of Ernest Rutherford. Rutherford is the New Zealand-born British physicist who is considered the Father of Nuclear Physics.
Rutherford is directly responsible for a number of important discoveries involving the study of nuclear science and radioactivity. He was the first to outline the rules governing radioactive decay and how it involved changes from one element to another in the case of alpha and beta decay. He also came up with the terms alpha, beta, and gamma radiation. He identified alpha radiation was identical to a helium nucleus. Rutherford identified the concept of half-life of a radioactive substance half of any amount of the substance took the same amount of time to decay. He showed that the nucleus of an atom is a dense, positively charged object. He coined the term proton for the positively charged part of the atom’s nucleus. Rutherford was awarded the 1908 Nobel Prize in Chemistry for his investigations into the disintegration of elements and the chemistry of radioactive substances.
He very nearly had to give up physics after graduation. His undergraduate degree was a Bachelor of Arts in Pure Mathematics, Latin, Applied Mathematics, English, French, and Physics. He continued his studies into physics and mathematics and concentrated on the study of electricity and magnetism and earned his Master of Arts. After all this study, he found finding a permanent job difficult in New Zealand as a physicist or a school teacher. He knew a scholarship was generally available to study in an English school every other year. He decided to return to school and try for this scholarship. He considered returning to study medicine but instead chose chemistry. When the scholarship became available, Rutherford was one of two candidates up for selection. He was not the one the University chose. Fortunately for him, the one that was chosen could not accept and Rutherford got the scholarship.
This scholarship took him to Cambridge under J. J. Thompson at the Cavendish Laboratory. He was given the task of experimenting with radio wave transmission in gases. He managed to detect radio waves over a distance of half a mile which was the record for a brief time before Marconi heralded in radio. After Henri Becquerel and the Curies announced their discoveries of radiation, he shifted his focus to this new field. This would be the beginning of the many important discoveries mentioned earlier.
Rutherford was a mentor to many important names of nuclear physics. One was James Chadwick, who won the Nobel Prize in Physics in 1935 for discovering the neutron which Rutherford had predicted to exist. Another was Niels Bohr, who won the Nobel Prize in Physics in 1922 for the theory of how electrons orbited Rutherford’s nucleus. Henry Moseley, who established atomic numbers identify an element, John Cockroft and Ernest Walton, the team that built the first high-energy accelerator, Robert Oppenheimer, later to be known as the father of the atomic bomb, and Hans Geiger, inventor of the Geiger tube to detect radiation all worked under Rutherford’s direction at Cambridge.
Rutherford is a national hero in his native New Zealand where his likeness is on the $100 note. Element 104 is named rutherfordium in his honor.
Notable Science History Events for October 19
2004 – Lewis Urry died.
Urry was a Canadian chemical engineer who invented the alkaline and lithium battery. While working for the Eveready battery company, he was attempting to extend the life of the current battery technology. He found a combination of manganese dioxide and zinc powder with an alkaline substance outlasted regular carbon-zinc batteries by nearly 40 times. Lithium batteries use lithium as the anode of the battery and can supply higher voltages and last longer than alkaline batteries.
1960 – Craig Mello was born.
Mellow is an American biologist who shares the 2006 Nobel Prize in Medicine with Andrew Fire for the discovery of RNA interference. RNA interference is a method where cells determine which part of the genetic information will be active and the magnitude of the effect.
1937 – Ernest Rutherford died.
1916 – Jean Dausset was born.
Dausset was a French immunologist who shares the 1980 Nobel Prize in Medicine with George Snell and Baruj Benacerraf for their discoveries concerning the genetic structures in a cell that regulate the immune response. He investigated the loss of white blood cells that occurs after a patient receives a blood transfusion. He found the new white blood cells would be selectively destroyed by the body’s immune response because of the presence of human leukocyte antigens. The presence of these antigens helps identify compatibility for tissue transplants.
1910 – Subrahmanyan Chandrasekhar was born.
Chandrasekhar was an Indian-born American astrophysicist who was awarded half the 1983 Nobel Prize in Physics for his theories of the evolution and structure of stars. He demonstrated the upper limit, or Chandrasekhar limit, of the mass of a white dwarf star. He also studied the theories of gravitational waves, black holes, and stellar dynamics. The orbiting x-ray telescope deployed by the Space Shuttle Challenger is named the Chandra X-Ray Observatory in his honor.
1909 – Marguerite Catherine Perey was born.
Perey was a French physicist who discovered the element francium. She found the elusive element while investigating lanthanum samples. Francium is produced by the alpha disintegration of actinium and has a very short half-life of only 22 minutes.
1802 – Charles Wheatstone died.
Wheatstone was a British scientist who developed a method to determine electrical resistance called the Wheatstone bridge. He also invented the Playfair cipher that was used by the British well into World War I to encrypt messages. He also determined that electricity had a ‘speed’ and was not instantaneous.
1856 – Edmund Beecher Wilson was born.
Wilson was an American biologist who discovered the chromosomal method to determine the sex of an embryo. He found males will have XY chromosomes and females will have XX chromosomes. He was also the first to identify the supernumerary B-chromosomes.