Editing Wave–particle duality (section)

=== Wave-particle duality of light ===
In the late 17th century, Sir [[Isaac Newton]] had advocated that light was [[Corpuscular theory of light|corpuscular]] (particulate), but [[Christiaan Huygens]] took an opposing wave description. While Newton had favored a particle approach, he was the first to attempt to reconcile both wave and particle theories of light, and the only one in his time to consider both, thereby anticipating modern wave-particle duality.<ref>{{Cite book |last=Finkelstein |first=David Ritz |author-link=David Finkelstein |url=https://books.google.com/books?id=OvjsCAAAQBAJ&pg=PA156 |title=Quantum Relativity |date=1996 |publisher=Springer Berlin Heidelberg |isbn=978-3-642-64612-6 |location= |pages=156, 169–170 |language=en |doi=10.1007/978-3-642-60936-7}}</ref><ref>{{Cite book |last=Arianrhod |first=Robyn |author-link=Robyn Arianrhod |url=https://books.google.com/books?id=ODDwiGtK1RQC&pg=PA232 |title=Seduced by Logic: Émilie Du Châtelet, Mary Somerville and the Newtonian Revolution |date=2012 |publisher=Oxford University Press |isbn=978-0-19-993161-3 |location=New York |pages=232 |language=en}}</ref> [[Thomas Young (scientist)|Thomas Young]]'s [[Young's interference experiment|interference experiments]] in 1801, and [[François Arago]]'s detection of the [[Poisson spot]] in 1819, validated Huygens' wave models. However, the wave model was challenged in 1901 by [[Planck's law]] for [[black-body radiation]].<ref>{{Cite journal |last=Planck |first=Max |date=1901 |title=Ueber das Gesetz der Energieverteilung im Normalspectrum |journal=Annalen der Physik |language=de |volume=309 |issue=3 |pages=553–563 |doi=10.1002/andp.19013090310|doi-access=free }}</ref> [[Max Planck]] heuristically derived a formula for the observed spectrum by assuming that a hypothetical electrically charged [[Oscillation|oscillator]] in a cavity that contained black-body radiation could only change its [[energy]] in a minimal increment, ''E'', that was proportional to the frequency of its associated [[electromagnetic wave]]. In 1905 [[Albert Einstein]] interpreted the [[photoelectric effect]] also with discrete energies for photons.<ref>{{Cite book |last=Einstein |first=Albert |title=The collected papers of Albert Einstein. 3: The Swiss years: writings, 1909 - 1911: [English translation] |date=1993 |publisher=Princeton Univ. Pr |isbn=978-0-691-10250-4 |location=Princeton, NJ}}</ref> These both indicate particle behavior. Despite confirmation by various experimental observations, the [[photon]] theory (as it came to be called) remained controversial until [[Arthur Compton]] performed a [[Compton effect|series of experiments]] from 1922 to 1924 demonstrating the momentum of light.<ref name="Whittaker2">{{Cite book |last=Whittaker |first=Edmund T. |title=A history of the theories of aether & electricity. 2: The modern theories, 1900 - 1926 |date=1989 |publisher=Dover Publ |isbn=978-0-486-26126-3 |edition=Repr |location=New York}}</ref>{{rp|211}} The experimental evidence of particle-like momentum and energy seemingly contradicted the earlier work demonstrating wave-like interference of light.