29/09/2025
It's September 29. Let me introduce you to an Italian man who was one of very few physicists to excel in both & physics. He made significant contributions to the development of statistical mechanics, quantum theory, and nuclear & particle physics. Today, Particles that obey the exclusion principle are called , in his honour. That great Italian man is our "scientist of the day" today.
It's the birthday of , one of the most significant figures in physics in the 20th century - - -
(Scientist of the Day - 29 September)
Fermi was the enigmatic physicist, teacher, mentor and the creator of the world's first nuclear reactor, the Chicago Pile 1. His first major contribution involved the field of statistical mechanics. After formulated his exclusion principle in 1925, Fermi followed with a paper in which he applied the principle to an ideal gas, employing a statistical formulation now known as statistics. Today, particles that obey the exclusion principle are called fermions.
Pauli later postulated the existence of an uncharged invisible particle emitted along with an electron during beta decay, to satisfy the law of conservation of energy. Fermi took up this idea, developing a model that incorporated the postulated particle, which he named the neutrino. His theory, later referred to as Fermi's interaction and now called weak interaction, described one of the four fundamental interactions in nature.
Through experiments inducing radioactivity with the recently discovered neutron, Fermi discovered that slow neutrons were more easily captured by atomic nuclei than fast ones, and he developed the Fermi age equation to describe this. After bombarding thorium and uranium with slow neutrons, he concluded that he had created new elements. Although he was awarded the for this discovery, the new elements were later revealed to be nuclear fission products.
