The stamp shows Danish physicist Niels Bohr, the hydogen atom and Bohr’s formula for the different of any two hydrogen energy levels.
Niels Bohr won the Nobel Prize for Physics in 1922. According to the Nobel website:
“In 1913, Niels Bohr proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities. Electrons should move around the nucleus but only in prescribed orbits. When jumping from one orbit to another with lower energy, a light quantum is emitted. Bohr’s theory could explain why atoms emitted light in fixed wavelengths.“
You can now picture me nodding as if I know what that meant.
I just read the version written for dummies (link below) and now I can convincingly use the words “ground state” and “excited” in the context of Atomic Theory, but still without a clue what it all means. Luckily for me, Niels Bohr was also an interesting dude who helped Jewish scientists escape the Nazis (good), got involved with the Manhattan Project (mixed) and advocated for international cooperation around peaceful uses of nuclear energy (good).
https://www.nobelprize.org/prizes/physics/1922/bohr/facts/
https://www.dummies.com/education/science/chemistry/atomic-structure-the-bohr-model/
https://en.wikipedia.org/wiki/Niels_Bohr
Stamp of the Day 