Editing Tyndall effect (section)

== History ==
Prior to his discovery of the phenomenon, Tyndall was primarily known for his work on the absorption and emission of radiant heat on a molecular level. In his investigations in that area, it had become necessary to use air from which all traces of floating dust and other [[particulates]] had been removed, and the best way to detect these particulates was to bathe the air in intense [[light]].<ref>Reported in a 10-page biography of Tyndall by [[Arthur Whitmore Smith]], a professor of physics, writing in an American scientific monthly in 1920; [https://archive.org/stream/contributions05michuoft#page/n90/mode/1up available online].</ref> In the 1860s, Tyndall did a number of experiments with light, shining beams through various gases and liquids and recording the results. In doing so, Tyndall discovered that when gradually filling the tube with smoke and then shining a beam of light through it, the beam appeared to be blue from the sides of the tube but red from the far end.<ref>{{Cite web |title=John Tyndall's blue sky apparatus |url=https://www.rigb.org/our-history/iconic-objects/iconic-objects-list/tyndall-blue-sky |access-date=2021-03-08 |website=Royal Institution |language=en}}</ref> This observation enabled Tyndall to first propose the phenomenon which would later bear his name.

In 1902, the [[ultramicroscope]] was developed by [[Richard Adolf Zsigmondy]] (1865–1929) and [[Henry Siedentopf]] (1872–1940), working for [[Carl Zeiss AG]]. Curiosity about the Tyndall effect led them to apply bright sunlight for illumination and they were able to determine the size of 4 nm small [[gold]] nanoparticles that generate the [[cranberry glass]] colour. This work led directly to Zsigmondy's [[Nobel Prize for chemistry]].<ref name=zmond>{{cite book | chapter=Richard Adolf Zsigmondy: Properties of Colloids | title=Nobel Lectures, Chemistry 1922–1941 | chapter-url=http://nobelprize.org/nobel_prizes/chemistry/laureates/1925/zsigmondy-lecture.html | location=Amsterdam | publisher=Elsevier Publishing Company | year=1966 }}</ref><ref name=mappes12>{{cite journal |doi=10.1002/anie.201204688|pmid=23065955|title=The Invention of Immersion Ultramicroscopy in 1912-The Birth of Nanotechnology?|year=2012|last1=Mappes|first1=Timo|last2=Jahr|first2=Norbert|last3=Csaki|first3=Andrea|last4=Vogler|first4=Nadine|last5=Popp|first5=Jürgen|last6=Fritzsche|first6=Wolfgang|journal=Angewandte Chemie International Edition|volume=51|issue=45|pages=11208–11212}}</ref>