Biography: John Dalton

John Dalton (1766 – 1844) was an English physicist and chemist, a

teacher in Manchester and a professor at Oxford University. Dalton was a
man of diverse interests, although his greatest achievements were in the
field of chemistry. Dalton introduced atomic theory by explaining the law
of constancy of chemical composition, and formulating the laws of partial
pressures and multiple proportions. He also carried out numerous tests
on gas absorption in liquids and thermal expansion of gases, and de-
scribed the condition known as daltonism. He regularly observed the
weather, studied the phenomenon of aurora Polaris and explained what
causes the trade winds.

John Dalton was born on September 6, 1766 in longing to the Manchester Literary and Philosoph-
Eaglesfield, Cumberland, England. He was born to ical Society, where he conducted most of his
an impoverished family. His father was a weaver chemical experiments and weather observations.
and owned a small piece of land. Despite their In 1799, the Society moved out of Manchester, but
poor financial situation, John received a good gen- Dalton remained in the city giving private lessons
eral education. However, he soon left school and for two shillings per hour.
started helping his father. Dalton was a Quaker. He wore a traditional
When John was 12, he started working as a grey coat, a white scarf on his neck, knee-breeches,
teacher in a local school. He earned his living and grey hose and boots with buckles. In the company
provided himself with a quiet, untroubled life. Me- of other people he was tense and often felt uncom-
teorology was his passion. He constructed barom- fortable. He never succeeded as a lecturer because
eters and other scientific instruments used in this he lacked charisma. He also never married, claim-
field. He began to keep a diary where he entered ing that he could not afford to have a wife.
his weather observations. During his life he made Dalton had a great interest in weather observa-
more than 200,000 observations and published tions and he began doing research on atmospheric
them as a book in 1793. composition. He collected air samples from differ-
Young Dalton was busy teaching at school, ent places on Earth and observed that atmospheric
helping his father, and studying Latin, Greek, and composition is the same regardless of the location.
natural sciences. After two years he moved to Dalton also proved that the atmosphere is not a
Kendal where he began teaching at the school run chemical compound, but instead is a composition
by his older brother, Jonathan. After twelve years, of various gases. He stated that the total pressure
he travelled to Manchester, where he was appoint- exerted by the mixture of gases is equal to the sum
ed as professor at the Warrington Academy. Dur- of the partial pressures of individual gases. This
ing this time, he devoted every spare moment to observation later became known as Dalton's law of
conducting physics experiments. partial pressures, or simply Dalton's law.
In 1781, he began teaching high school math- This prominent scholar was very curious about
ematics and in 1793 he became a teacher of math- one particular aspect of gases. John knew that car-
ematics and natural philosophy at the New Col- bon dioxide is quite heavy, oxygen is lighter, ni-
lege in Manchester. There he met Robert Owen, trogen is even lighter and water vapor is the light-
who introduced him to the Manchester Literary est of the four, being two times lighter than carbon
and Philosophical Society. Soon Dalton became a dioxide. Knowing this, Dalton wondered why
secretary and since 1817 was the President of the there was a layer of water vapor above the ground,
Society. Over a period of 50 years, Dalton present- instead of the layer of carbon dioxide. Dalton tried
ed 116 of his scientific works. In addition, Dalton to imagine the structure of the above mentioned
created his private laboratory in the building be- compounds to explain the concept of diffusion.

Biography: John Dalton 1

Storytelling Teaching Model: wiki.science-stories.org
This was the beginning of his detailed studies, mother and gave her a colorful piece of fabric as a
which resulted in the creation of a highly contro- gift. He was surprised when his mother said that
versial theory. In this theory, Dalton stated that the fabric was red, because he thought that it was
everything is made of atoms. as grey as his coat. He was very concerned about
Dalton's atomic theory can be described in four not being able to tell the difference between grey,
main points: green, and red. Later, this inability was called dal-
1) All substances are made of atoms. tonism after him, or as we now know it, color
2) Atoms of the same substance are the same blindness.
and have the same mass; atoms of different John Dalton died in Manchester on July 27,
substances differ from each other and have 1844. In his memory, Owens College created a
different masses. scholarship fund. One of the first students who
3) A chemical reaction involves connection, received it was J. J. Thompson. The atomic mass
dividing and exchanging atoms. In other unit (Da) was named in Dalton’s honor.
words, the atom is a basic unit involved in a
chemical reaction and cannot be subdivid- References:
ed. Fierz-Dawid, H. E. (1958). Historia rozwoju chemii. Warsza-
wa: Państwowe Wydawnictwo Naukowe.
4) If two or more compounds made of the http://www.encyklopedia.pwn.pl
same elements exist, the simplest com- http://www.britannica.com
pound of all will contain one atom of every http://www.portalwiedzy.onet.pl
element present there. http://www.wikipedia.pl
Wróblewski, A. K. (1998). Wiedza i Życie.
Dalton presented this theory to the Royal Insti- Wróblewski, A. K. (2007). Historia fizyki. Warszawa: PWN.
tution in 1803. More precise details were included Wróblewski, A. K. (1999). Uczeni w anegdocie. Warszawa:
in the general “System of Chemistry,” which was Prószyński i Ska.

later written by the chemist Thomas Thomson.

Dalton conducted an analysis of two molecules Biography: John Dalton was edited by Stephen Klassen and
Cathrine Froese Klassen and is based, in part on Historical
of carbon monoxide and found that in one of
Background: Atoms written by Peter Heering.
them the mass of oxygen is two times bigger than
the mass of carbon. He suspected that a rule must
Biography: John Dalton was written by Emilia Dobrowolska
exist to explain this phenomenon and conducted with the support of the European Commission (project
an analysis using nitrous oxide. This time, he care- 518094-LLP-1-2011-1-GR-COMENIUS-CMP) and Polish
fully examined three gases, and found that the ra- Association of Science Teachers, Poland. This publication
tio of the mass of nitrogen in relation to the mass reflects the views only of the author, and the Commission
cannot be held responsible for any use which may be made of
of oxygen was 7:8, in a second compound 7:16,
the information contained therein.
and in a third, 7:4. Based on his analyses he for-
mulated the law of multiple proportions. This law
says that if two elements (A and B) form more
than one compound, then the ratios of the masses
of element B which combine with a fixed mass of
A, are small integers.
In 1822, Dalton was elected as a member of the
Royal Society and eight years later he was appoint-
ed as one of the foreign associates of the French
Académie des Sciences. He was highly respected
by many scientists in Europe and the King of Eng-
land granted him a pension which enabled him to
retire from delivering lectures at the Academy.
One event in Dalton’s life is especially worth
mentioning: One day Dalton decided to visit his

2 Biography: John Dalton

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