Joseph Black

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For other persons named Joseph Black, see Joseph Black (disambiguation).
Joseph Black
Mezzotint engraving after Sir Henry Raeburn
Born 16 April 1728
Bordeaux, France
Died 6 December 1799
Edinburgh
Nationality Scottish
Fields Medicine, physics, and chemistry
Known for Latent heat, specific heat, and the
discovery of carbon dioxide
Influenced James Watt

Joseph Black (16 April 1728 – 6 December 1799[1]) was a Scottish physician, physicist, and chemist, known for his discoveries of latent heat, specific heat, and carbon dioxide. He was a founder of thermochemistry who developed many pre-thermodynamics concepts, such as heat capacity, and was the mentor for James Watt. The chemistry buildings at both the University of Edinburgh and the University of Glasgow are named after Black.

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[edit] Early years

Black was born in Bordeaux, France, where his father, who was from Belfast, Ireland, was engaged in the wine trade. His mother was from Aberdeenshire, Scotland, and her family was also in the wine business. Joseph had twelve brothers and sisters.[2] He entered the University of Glasgow when he was eighteen years old, and four years later he went to Edinburgh to further his medical studies.

Black was a friend of James Watt, who first began his studies on steam power at Glasgow University in 1761. Black also was a member of the Poker Club and associated with David Hume, Adam Smith, and the literati of the Scottish Enlightenment. Black never married. He died in Edinburgh at the age of 71, and is buried there in Greyfriars Kirkyard.

[edit] Professional life

While at the University of Edinburgh, Black studied properties of carbon dioxide (CO2).[3] One of his experiments involved placing a flame and mice into the carbon dioxide. Because both entities died, Black concluded that the air was not breathable. He named it 'fixed air' in 1754. In 1756 Black described how carbonates become more alkaline when they lose carbon dioxide, whereas the taking-up of carbon dioxide reconverts them. He was the first person to isolate carbon dioxide in a perfectly pure state. This was an important step in the history of chemistry as it helped people to realize that air was not an element, but rather was composed of many different things. Black's work also aided in discrediting the belief in a fiery principle called phlogiston.

In about 1750, Joseph Black developed the analytical balance based on a light-weight beam balanced on a wedge-shaped fulcrum. Each arm carried a pan on which the sample or standard weights was placed. It far exceeded the accuracy of any other balance of the time and became an important scientific instrument in most chemistry laboratories.[4].

In 1757, he was appointed Regius Professor of the Practice of Medicine at the University of Glasgow.

In 1761 Black deduced that the application of heat to ice does not cause its immediate liquefaction, rather the ice absorbed the heat without a rise in temperature.[5] Additionally, Black observed that the application of heat to boiling water does not result in immediate evaporation. From these observations, he concluded that the heat applied must have combined with the ice particles and boiling water and become latent. The theory of latent heat marks the beginning of thermal science.[6]

Black's theory of latent heat was one of his more-important scientific contributions, and one on which his scientific fame chiefly rests. He also showed that different substances have different specific heats. This all proved important not only in the development of abstract science but in the development of the steam engine.[7]

[edit] See also

Ice calorimeter used by Lavoisier and Laplace, and based on Black’s discovery of latent heat

[edit] References

  1. ^ Guerlac, Henry (1970-80). "Black, Joseph". Dictionary of Scientific Biography. 2. New York: Charles Scribner's Sons. pp. 173-183. ISBN 0684101149. 
  2. ^ Lenard, Philipp (1950). Great Men of Science. London: G. Bell and Sons. pp. 129. ISBN 0-8369-1614-X.  (Translated from the second German edition)
  3. ^ "Experiments upon Magnesia Alba, Quick-Lime, and some other Alkaline Substances". http://web.lemoyne.edu/~giunta/black.html. Retrieved on 2008-03-08. 
  4. ^ "Equal Arm Analytical Balances". http://history.nih.gov/exhibits/balances/index.html. Retrieved on 2008-03-08. 
  5. ^ Ogg, David (1965). Europe of the Ancien Regime: 1715-1783. Harper & Row. 
  6. ^ Ogg, David (1965). Europe of the Ancien Regime: 1715-1783. Harper & Row. pp. 117 and 283. 
  7. ^ Ogg, David (1965). Europe of the Ancien Regime: 1715-1783. Harper & Row. pp. 283. 

[edit] Further reading

[edit] External links

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