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John Dalton


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John Dalton described color blindness; for many years color blindness was called Daltonism. <ref>(2009).John Dalton Biography. Retrieved January 31, 2009, from http://www.who2.com/johndalton.html</ref>

John Dalton (1766-1844) was an English chemist who proposed the first modern atomic theory in his text A New System of Chemical Philosophy.<ref>Science World</ref> Dalton held that the atom is a solid sphere. This is in contrast to other atomic models developed after the discovery of the subatomic particles. CITATION REQUIRED


Early Years

Caption: John Dalton
Engraving of a painting of John Dalton
Source:Frontispiece of John Dalton and the Rise of Modern Chemistry by Henry Roscoe

John Dalton was a English chemist born on September 6, 1766. <ref name="basic">basic famous people</ref> He was born at Eagles Field, England into a Quaker family. <ref name="basic" /> He kept a meteorologist diary where he wrote over 200,000 observations. He had his first publication in 1793 which was named Meteorologist Observations & Essays. <ref>(2000). John Dalton. Retrived January 31, 2009, from http://angelfire.com/zine/baptistsurfer/Dalton.html</ref>

John Dalton was never married and only had a couple of close friends. In 1837, Dalton suffered his first stroke. A year later he had a second stroke that left him with a speech impediment. On May 1844 he suffered a third stroke two months before his death on July 27 1844. CITATION REQUIRED

Education

John received his early education from his father and from John Fletcher, teacher of the Quakers' school at Eagles Field. This youthful venture was not successful, the amount he received in fees being only about five shillings a week, and after two years he took to farm work. He attended John Fletcher’s Quaker grammar school in Eagles Field. When John was only 12 years old, Fletcher turned the school over to John’s older brother, Jonathan.


Career

In 1793 he moved to Manchester (Country?) and became a teacher of mathematics and natural philosophy at a dissenting academy. CITATION REQUIRED A year after his move to Manchester he was accepted into the Manchester Literary Philosophical Society. He was president of the Manchester Literary Philosophical Society until his death. CITATION REQUIRED


Contributions

Published Meteorological Observations and Essays.

In 1800 John Dalton became secretary of the exclusive society he had joined. CITATION REQUIRED Over the course of the year he wrote four important essays describing the effects of mixed gases, steam, vapor, and evaporation. He also wrote hoe they were affected in different temperatures and in a vacuum or air. They were entitled "Experimental Essays" and were published in the memories of his society in 1802. He then published several topics in 1803 containing his law of partial pressures otherwise known as Dalton's law. <ref>Feldman, Anthony, Ford, Peter. (2009). John Dalton. Retrieved January 31, 2009, from http://www.robinsonlibrary.com/sciance/chemistry/biography/dalton.htm</ref>

Dalton's Atomic Theory

Dalton's biggest achievement was his contribution to the atomic theory. It is believed that John got his inspiration of the atomic theory by the study of the physical properties of the atmosphere and other gases. <ref>Gale, Thomson. (2006).Encyclopedia of World Biography on John Dalton. Retrieved on January 31, 2009, from www.bookrags.com/biography/john-dalton </ref> The first published information that there is concerned his curiosity of the atomic theory was at the end of his paper on the absorption of gases. It read "Why does not water admit its bulk of every kind of gas alike? This question I have duly considered, and though I am nearly persuaded that the circumstance depend on the weight and number of the ultimate particles of the several gases."

The five main points that Dalton wrote on the Atomic Theory are:

  • Elements are made up of tiny particles called atoms
  • All atoms of a given element are identical
  • The atoms of a given elements are different from those of any there element
  • Atoms of one element can combine with atoms of other elements to form chemical compounds
  • Atoms cannot be created, divided into smaller particles, nor destroyed in the chemical process

There was a lot of controversy surrounding Dalton's rule of great simplicity. CITATION REQUIRED The rule stated that when atoms combine in only one ratio it must presume to be a binary one, unless some cause appears to the contrary. This rule made it appear that the formula for water was OH and ammonia was NH. Although there was a lot of uncertainty surrounding his theory the main principals are still uses today. The importance of his contribution to the atomic theory can be compared as Antoine Laurent Lavosier's contribution to oxygen-base chemistry.

Law of Partial Pressures

References

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