## 1913 – quantum theory

In 1913, Neils Bohr introduced a new model of the atom that included electron orbitals tied to levels of energy.

**Understanding Quantum Physics 01/04** – [youtube.com]

Quantum Physics is the branch of Science that studies and describes reality at the atomic (molecules and atoms) and the subatomic (electrons, protons, and even smaller particles) level of matter.

These descriptions include the simultaneous wave-like and particle-like behavior of both matter and radiation (“waveparticle duality”).

**Understanding Quantum Physics 02/04** – [youtube.com]

**Understanding Quantum Physics 03/04** – [youtube.com]

**Understanding Quantum Physics 04/04** – [youtube.com]

PRECURSOR:

1897 – electron discovered (JJ Thomson)

1901 – Planck postulate, packetized energy **(Planck)**

1902 – photoelectric effect (Lenard)

1905 – photoelectric effect (Einstein)

CONCURRENT:

1910 – Haas model with quantum electron orbitals was rejected

1911 – Rutherford model

1923 – electron scattering (Compton)

1924 – photon states (Bose)

1924 – matter waves (deBroglie)

1925 – Matrix mechanics (Heisenberg)

**1926 – Wave mechanics (Schrodinger)**

1926 – term “photon” created

1927 – uncertainty principle (Heisenberg)

1927 – first quantum field theories

1928 – Dirac equation

SUBSEQUENT:

SEE ALSO:

**1885 – Bohr – bio**

electron spin

timeline of the atom