Drowning in the ocean of quantum field theory, your correspondent grasps Planck and emerges to sputter another question.

Planck's constant represents energy's proportionality to frequency.

It found application in Einstein's theory of photoelectricity. Electrons freed by the photoelectric effect exhibit a measurable kinetic energy independent of light intensity but linearly dependent on light frequency. More light intensity on a system simply releases more electrons.

The question is, why was this surprising? If one assumes as is most natural an infinitely subconsistuent structure to the universe, would not some internal architecture of the observed systems "fracture", so to speak, along predetermined lines upon exposure to the stimulus?