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SUMMARY:Is water H2O? - Prof Hasok Chang\, Department of History and Philo
 sophy of Science\, Cambridge
DTSTART:20111201T190000Z
DTEND:20111201T200000Z
UID:TALK33716@talks.cam.ac.uk
CONTACT:John O'Toole
DESCRIPTION:Every schoolchild knows that water is H2O\, but it was a terri
 bly difficult thing for scientists to learn originally. The story begins w
 ith the Chemical Revolution of the late 18th century\, in which Lavoisier'
 s notion that water was a compound of oxygen and hydrogen flew in the face
  of the traditional wisdom that it was an element. Opposition to Lavoisier
  persisted in various corners\, for much longer than usually recognised. C
 avendish\, whose experiments had taught Lavoisier how to make water from h
 ydrogen and oxygen\, thought that hydrogen and oxygen were merely water wi
 th an excess or a deficit of 'phlogiston'. Priestley\, who had made oxygen
  before Lavoisier\, adopted Cavendish's view of water and defended it to h
 is death in 1804. Even the electrolysis of water in 1800 failed to produce
  a complete consensus\, and in fact a significant condundrum was raised by
  the macroscopic distance between the locations of oxygen-production and h
 ydrogen-production in electrolysis. Disputes about the mechanism of electr
 olysis continued throughout the 19th century. And deciding that water was 
 a compound was by no means the end of the story. When Dalton published his
  atomic theory in 1808\, he gave the formula of water as HO\, with atomic 
 weights of H and O as (roughly) 1:8. Avogadro's H2O formula was published 
 shortly after this\, but it was initially rejected by the majority of chem
 ists. It took half a century of debates\, and in the end insights from org
 anic chemistry\, before consensus was reached on the modern set of atomic 
 weights and molecular formulae including H2O. This story of the changing o
 ntology of water is not only fascinating in itself\, but illustrates many 
 important points about the nature of scientific knowledge and its developm
 ent.\n\n\nProf Chang’s research interests include history and philosophy
  of chemistry and physics from the 18th century onward\; philosophy of sci
 entific practice\; other topics in the philosophy of science\, including m
 easurement\, realism\, evidence\, pluralism and pragmatism. His book\, Is 
 Water H2O? Evidence\, Pluralism and Realism\, will be available shortly fr
 om Boston Studies in the Philosophy of Science (Springer).\n\nFree admissi
 on. Open to the public. Suitable for GCSE students. No tickets\, so arrive
  early to get a good seat. \n
LOCATION:Pfizer Lecture Theatre\, Department of Chemistry\, Lensfield Road
 \, Cambridge
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