The Gate to the Quanta
On May 18th, 1899 Planck reported about his work on heat radiation at the Prussian Academy of Science (Preußische Akademie der Wissenschaften) in Berlin. Thereby he mentioned the new natural constant h, called today the Planck’s constant, for the first time. To explain his radiation formula Planck had to assume tiny amounts of energy, which are calculated with the help of the constant h. This idea led to the definition of quantum jumps and was presented by Planck to the Physical Society of Berlin on December 14th, 1900.
In the beginning of the 20th century Max Planck opened the gate to a new world: the "micro-world", the world of discontinuous energy quanta E, E = h × ν and Schrödinger's Ψ-function.
Discontinuity also exists in daily life; for example, the flux of money is discontinuous! Every currency has its smallest unit (coin), which can change the possessor by the payment of goods. In a figurative sense it is also valid for the microscopic world of physics.