Top Questions
What is John Dalton best known for?
John Dalton is best known for what became known as
Dalton’s law
, which posits that the total pressure of a gaseous mixture is equal to the sum of the partial
pressures
of the individual component
gases
, partial pressure being the pressure that each gas would exert alone within the volume of the mixture at the same
temperature
.
Why was John Dalton so influential?
John Dalton based his partial pressures
theory
on the idea that only like
atoms
repel one another, whereas unlike atoms appear to react indifferently. This notion was erroneous, but it helped to explain why each gas in a mixture behaved independently, serving the purpose of showing that atoms of all kinds are not alike.
What were John Dalton’s other contributions to chemistry?
John Dalton developed a crude method for measuring the masses of the
elements
in a
compound
. His
law of multiple proportions
states that when two elements form more than one compound, masses of one element that combine with a fixed mass of the other are in a
ratio
of small whole numbers.
What were John Dalton’s other scientific contributions beyond chemistry?
John Dalton posited, against contemporary opinion of the time, that the
atmosphere
was a physical mixture of approximately 80 percent
nitrogen
and 20 percent
oxygen
rather than a specific compound of elements. Dalton’s notion has been upheld by scientific observation ever since.
John Dalton
(born September 5 or 6, 1766, Eaglesfield,
Cumberland
, England?died July 27, 1844, Manchester) was an English meteorologist and chemist, a pioneer in the development of modern
atomic theory
.
Early life and education
Dalton was born into a
Quaker
family of tradesmen; his grandfather Jonathan Dalton was a shoemaker, and his father, Joseph, was a weaver. Joseph married Deborah Greenup in 1755, herself from a prosperous local Quaker family. Dalton was the youngest of their three
offspring
who survived to adulthood. He attended
John Fletcher’s
Quaker
grammar school
in Eaglesfield. When John was only 12 years old, Fletcher turned the school over to John’s older brother, Jonathan, who called upon the younger Dalton to assist him with teaching. Two years later the brothers purchased a school in
Kendal
, where they taught approximately 60 students, some of them boarders.
As a teacher, Dalton drew upon the experiences of two important mentors:
Elihu Robinson, a Quaker gentleman of some means and scientific tastes in Eaglesfield, and
John Gough, a mathematical and classical scholar in Kendal. From these men John acquired the rudiments of
mathematics
,
Greek
, and
Latin
. Robinson and Gough were also amateur meteorologists in the Lake District, and from them Dalton gained practical knowledge in the construction and use of meteorologic instruments as well as instruction in keeping daily
weather
records. Dalton retained an
avid
interest in meteorologic measurement for the rest of his life.
Early scientific career
In 1793 Dalton moved to
Manchester
to teach mathematics at a dissenting academy, the New College. He took with him the proof sheets of his first book, a collection of essays on meteorologic topics based on his own observations together with those of his friends John Gough and Peter Crosthwaite. This work,
Meteorological Observations and Essays
, was published in 1793. It created little stir at first but contained original ideas that, together with Dalton’s more developed articles, marked the transition of
meteorology
from a topic of general folklore to a serious scientific pursuit.
Britannica Quiz
Physics and Natural Law
Born and reared in
England’s
mountainous
Lake District
, Dalton was well placed to observe various meteorologic phenomena. He upheld the view, against contemporary opinion, that the
atmosphere
was a physical mixture of approximately 80 percent
nitrogen
and 20 percent
oxygen
rather than being a specific
compound
of
elements
. He measured the capacity of the air to absorb water vapour and the variation of its partial pressure with temperature. He defined
partial pressure
in terms of a physical law whereby every
constituent
in a mixture of gases exerted the same pressure it would have if it had been the only
gas
present. One of Dalton’s contemporaries, the British scientist
John Frederic Daniell
, later hailed him as the “father of meteorology.”
Soon after his arrival at Manchester, Dalton was elected a member of the Manchester Literary and Philosophical Society. His first contribution to this society was a description of the defect he had discovered in his own and his brother’s vision. This paper was the first publication on
colour blindness
, which for some time thereafter was known as Daltonism.
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