Final answer:
Quantum mechanics, sparked by Max Planck's discovery of energy quantization, revolutionized physics and led to modern atomic theories.
Step-by-step explanation:
Quantum mechanics initiated a profound shift in the understanding of atomic and subatomic processes. One of the pivotal contributors to quantum theory was Max Planck, who proposed that energy is quantized to explain black body radiation. His discovery laid the foundations for modern quantum mechanics and led to the realization that atomic spectra are evidence of the quantized nature of energy in atoms. The development of the standard model has clarified forces on a subatomic level, with ongoing research into a grand unified theory.
Advancing from this groundbreaking work, the development of the standard model of particle physics incorporated theories such as the electroweak theory and quantum chromodynamics. These theories elucidate the forces that govern subatomic particles, with quantum chromodynamics focusing on the strong force mediated by gluons. The quest for unification continues with physicists seeking evidence for grand unified theories that might reconcile all known forces.