$nd chemists hotly debated the question of whther atoms were real things. Einstein's statistical discussion of atomic behavior gave experimentalists a way to count atoms by looking through an ordinary microscope. [[Wilhelm Ostwald]], one of the leaders of the anti-atom school, later told [[Arnold Sommerfeld]] that he had been converted to a belief in atoms by Einstein's complete explanation of Brownian motion.
The second paper of 1905 proposed the idea of "light quanta" (now called [[photons]]) and showed how they could be used to explain such phenomena as the photoelectric effect. Einstein's theory of light quanta received almost no support from other physicists for nearly 20 years. It contradicted the wave theory of light that underlay [[James Clerk Maxwell]]'s equations for electromagnetic behavior. Even after experiments demonstrated that Einstein's equations for the photoelectric effect were splendidly accurate, his explanation was not accepted. In 1922, when he was awarded the Nobel Prize, and his work o