Why did Max Planck receive the 1918 Nobel Prize in Physics?

Max Planck received the 1918 Nobel Prize for Physics for his discovery of the quantum of action, now known as Planck’s constant (h), in 1900.21

This discovery laid the foundation for quantum theory, which revolutionized the scientific understanding of atomic and subatomic processes. Planck introduced the constant while developing an accurate mathematical formulation for the distribution of radiation emitted by a blackbody. To derive this formula, he determined that energy is emitted, transmitted, and absorbed in discrete packets called quanta, rather than continuously. This work fundamentally challenged classical physics and established the basis for modern quantum mechanics.2134