By "curve" I assume you mean "spectrum."
If you assume that electro-magnetic (EM) energy -- ie, "light" -- can exist in any size, then the spectrum of a glowing "black body" is impossible to explain.
If you make the (now simple, but, at the time, almost un-thinkable) assumption that EM energy can only exist in certain "chunks," and that the size of these chunks depends on the frequency of the EM wave, then the spectrum is quite easy to explain.
Max Planck called these chunks of light "quanta," and eventually they were called "photons."
It so happens that other phenomena we observe are similar: easy to explain with photons, impossible to explain without them.
Max Planck
Richard Feynman stated once that "if you think you understand quantum mechanics then you don't understand quantum mechanics". However it is possible to learn how to write and solve the equations of quantum mechanics to get answers that can be verified experimentally.
Max Planck proposed the quantum theory of radiation in 1900, which revolutionized our understanding of the behavior of electromagnetic radiation. Planck introduced the concept of energy quantization, where energy is emitted or absorbed in discrete units called quanta. This groundbreaking theory laid the foundation for quantum mechanics.
Elmer Samuel Imes applied infrared spectroscopy to the quantum theory to investigate the interactions of molecules with electromagnetic radiation and to provide experimental confirmation of quantum theory predictions. By studying the absorption and emission of infrared radiation by molecules, Imes was able to demonstrate the quantization of energy levels in molecules, supporting the principles of quantum mechanics.
Bohr.
Max Planck
The concept of quantum theory of radiation was introduced by Max Planck in 1900. Planck's theory proposed that radiation is emitted and absorbed in discrete packets of energy, known as quanta. This laid the foundation for the development of quantum mechanics.
Richard Feynman stated once that "if you think you understand quantum mechanics then you don't understand quantum mechanics". However it is possible to learn how to write and solve the equations of quantum mechanics to get answers that can be verified experimentally.
Max Planck proposed the quantum theory of radiation in 1900, which revolutionized our understanding of the behavior of electromagnetic radiation. Planck introduced the concept of energy quantization, where energy is emitted or absorbed in discrete units called quanta. This groundbreaking theory laid the foundation for quantum mechanics.
Elmer Samuel Imes applied infrared spectroscopy to the quantum theory to investigate the interactions of molecules with electromagnetic radiation and to provide experimental confirmation of quantum theory predictions. By studying the absorption and emission of infrared radiation by molecules, Imes was able to demonstrate the quantization of energy levels in molecules, supporting the principles of quantum mechanics.
Quantum Mechanics
He published his work in 1900. It was VERY FAR from a full quantum theory, it was only an attempt to explain the spectrum of black body radiation with the idea that light came in chunks he called "quanta." And he himself did not think these quanta actually existed, he only noted this as a mathematical curiosity.
The quantum of light, known as a photon, is significant in physics because it helps explain the behavior of light and other electromagnetic radiation. It plays a key role in the theory of quantum mechanics, which describes the behavior of particles at the smallest scales. Understanding the quantum nature of light has led to advancements in various fields, including quantum computing and telecommunications.
Classical free electron theory could not explain many physical properties. In 1928, Sommerfeld developed a new theory applying quantum mechanical concepts and Fermi-Dirac statistics to the free electrons in the metal. This theory is called quantum free electron theory.
Bohr.
The classical theory of solids is based on the assumption that atoms are fixed in a lattice structure and do not move. However, quantum mechanics shows that atoms in solids have wave-like properties and do exhibit movement. This discrepancy between classical theory and quantum mechanics makes classical theory inadequate for explaining the behavior of solids at the atomic level.
Albert Einstein - general theory of relativity Isaac Newton - laws of motion and universal gravitation Niels Bohr - atomic structure and quantum theory Marie Curie - research on radioactivity Max Planck - quantum theory of radiation Galileo Galilei - contributions to observational astronomy Richard Feynman - quantum electrodynamics Werner Heisenberg - principle of uncertainty Stephen Hawking - black hole radiation theory James Clerk Maxwell - equations of electromagnetism.