With the recent release of Oppenheimer, the story of J. Robert Oppenheimer, the ‘father of the atomic bomb‘, minds have, understandably, turned to the invention of the atomic bomb and further how the splitting of the atom came about. Something that we certainly never knew is that Manchester actually played a significant role in the discovery and splitting of the atom, and therefore our city was truly part of the Oppenheimer story.
The invention of the atomic bomb of course led to the bombings of Hiroshima and Nagasaki, Japan, in 1945, and is something that has been controversial ever since, with Oppenheimer famously conflicted by his own creation.
Many have looked back at the discovery of the atom, and splitting the atom, during this process of reflection on the atomic bomb, and in doing so it has been highlighted that Manchester is where much of it began. Manchester is the birthplace of nuclear physics and John Dalton – now known for being a street name and a building at Manchester Metropolitan University – was the man to put forward ‘Atomic Theory‘.
According to the Museum of Science and Industry here in Manchester, in 1803-1804 Dalton’s theory was based on the concept that each element consists of its own unique brand of indivisible atom; atoms of one element are all alike but they differ from atoms of other elements. Importantly, Dalton assigned atomic weights to the atoms of the 20 elements he knew of at the time. This was a revolutionary concept for the day, which would contribute to the development of the periodic table of the elements later in the 19th century.
This concept, that atoms of different elements are distinguished by differences in their weights, opened up new fields of experimentation. Each aspect of Dalton’s theory has since been amended or refined, but its overall picture remains as the basis of modern chemistry and physics.
Through his work, Dalton also pioneered the use of ball-and-stick models to illustrate the three-dimensional structure of molecules, which are often used in teaching to this day.
Following this discovery, it has now been over 100 years since Ernest Rutherford ‘split the atom‘ at The University of Manchester. In 1917, the Nobel Prize winner actually became the first person to create an artificial nuclear reaction in laboratories at the University. Rutherford’s discovery is now often described as ‘splitting the atom’ in popular accounts, but this should not be confused with the process of nuclear fission discovered later in the 1930s.
With help from colleague Patrick Blackett, Rutherford and his team became the first in history to initiate an artificial nuclear reaction, with Blackett later revealing the reaction mechanism. We now also know that the hydrogen nucleus emitted was actually a subatomic particle, now called the proton.
Professor Sean Freeman, Professor of Nuclear Physics and Head of the School of Physics & Astronomy at the University, explains: “This discovery, and the earlier work done by Rutherford that established the existence of an atomic nucleus itself, essentially established the field of nuclear physics right here in Manchester.”
Later painstaking research done by Patrick Blackett, at Rutherford’s suggestion in Cambridge in the 1920s, captured rare cloud chamber images that revealed the full detail of what was happening. The photographs showed some of the alpha particles were absorbed by the nitrogen nuclei. This process led to excess energy in the nitrogen nuclei, resulting in an oxygen atom and a hydrogen nucleus being emitted.
Professor Freeman suggests: “”Splitting the atom” is not a particularly good description of this work, given the detailed picture of the reaction revealed later by Blackett.
“This was also the discovery of the proton and Rutherford showed that the “nucleus of hydrogen” existed in the nucleus of other atoms and thus appeared as a basic building block. The first nuclear reaction initiated by a human and the discovery of the proton are big steps in themselves, but from these reactions you can also infer the sizes of nuclei.
“It also led to the development of nuclear accelerators – so that you could induce all sorts of different nuclear reactions.”
Dalton and Rutherford very clearly distinguished Manchester as being the birthplace for some of the most important discoveries in science, in the world, and the discovery and ‘splitting’ of the atom is the basis on which the Oppenheimer story was ultimately built. The discovery of nuclear fission in 1938 is even alluded to in the Oppenheimer film, but is an idea extended from the original splitting of the atom in Manchester, focusing on the radiation caused – see if you can catch it!
You can see John Dalton’s remaining equipment and work including molecular model balls, portraits of the man, and even his eyes donated posthumously (related to his research into colour blindness), at Manchester’s Science and Industry museum.