An insight into the life of John Dalton, the English Chemist who provided the foundation for the atomic theory, thus leading to the the study of chemistry as a separate subject. - Eisa Adil

1. John Dalton
Another Presentation by
Eisa Adil

2. Who was Dalton?
• John Dalton (6 September 1766 – 27 July
1844) was an English chemist.
• He provided the beginnings of the
development of a scientific atomic theory,
thus facilitating the development of chemistry
as a separate science.
• His contributions to physics, particularly to
meteorology, were also significant.

3. Who was Dalton?
• He is widely known for his research on Color
Blindness, also called Daltonism, in his honor.

4. Early Life
• John Dalton (1766–1844) was born into a modest
Quaker family in Cumberland, England, and
earned his living for most of his life as a teacher
and public lecturer.
• Until he was 11, he attended school, then at the
age of 12 became a teacher.
• After teaching 10 years at a Quaker boarding
school in Kendal, he moved on to a teaching
position in the growing city of Manchester.

5. Early Life
• There he joined the Manchester Literary and
Philosophical Society, which provided him
with a stimulating intellectual environment
and laboratory facilities.
• The first paper he delivered before the society
was on color blindness, which afflicted him
and is sometimes still called “Daltonism.”

6. Studies in Meteorology
• Dalton's lifelong interest in meteorology did
much to make that study a science.
• He began keeping records of the local weather
conditions, atmospheric pressure,
temperature, wind, and humidity in 1787, and
maintained them for 57 years until his death.
• During this time he recorded more than
200,000 values, using equipment which for
the most part was made by him.

7. Studies in Meteorology
• Dalton's interest in the weather gave him a
special interest in mixtures of gases, and his
earliest studies were concerned with
atmospheric physics.
• The formulation of his law of partial pressures
(Dalton's law) was announced in 1803.
• It defined the pressure of a mixture of gases
as the sum of the pressures exerted by each
component solely occupying the same space.

8. Studies in Meteorology
• In 1800 he studied the heating and cooling of
gases resulting from compression and
expansion, and in 1801 he formulated a law of
the thermal expansion of gases.
• His work on water vapor concentration in the
atmosphere, using a homemade dew-point
hygrometer, and his 1804 study of the effect
of temperature on the pressure of a vapor
brought him international fame.

9. The Atomic Theory
• Less than twenty years earlier, in the
1780's, Lavoisier ushered in a new chemical era by
making careful quantitative measurements which allowed
the compositions of compounds to be determined with
accuracy.
• By 1799 enough data had been accumulated for Proust to
establish the Law of Constant Composition ( also called the
Law of Definite Proportions).
• In 1803 Dalton noted that oxygen and carbon combined to
make two compounds. Of course, each had its own
particular weight ratio of oxygen to carbon (1.33:1 and
2.66:1), but also, for the same amount of carbon, one had
exactly twice as much oxygen as the other.
Antoine Lavoisier

10. The Atomic Theory
• This led him to propose the Law of Simple
Multiple Proportions, which was later verified
by the Swedish chemist Berzelius.
• In an attempt to explain how and why
elements would combine with one another in
fixed ratios and sometimes also in multiples of
those ratios, Dalton formulated his atomic
theory.
Antoine Lavoisier

11. Postulates of the Atomic Theory
All matter is composed of atoms
Atoms cannot be made or destroyed
All atoms of the same element are identical
Different elements have different types of atoms
Chemical reactions occur when atoms are rearranged
Compounds are formed from atoms of the
constituent elements.
Dalton's theory was based on the premise that the atoms of different
elements could be distinguished by differences in their weights. He
stated his theory in a lecture to the Royal Institution in 1803. The theory
proposed a number of basic ideas:

12. Later Life
• Dalton lived a simple life, kept to the doctrines of his
Quaker faith, and never married.
• During most of his life he had little money and was
almost excessively economical; however, by tutoring
and doing routine chemical work at low pay his few
wants were met.
• He had no flair for lecturing: his voice was rather harsh,
and he was inclined to be rather stiff and awkward in
manner. He is said to have had no grace in conversation
or in writing.
• Despite his lack of these social assets, he apparently
lived a quite happy life and had many friends.

13. Later Life
• In 1810 Dalton refused an invitation to join the Royal
Society but was finally elected in 1822 without his
knowledge.
• As his fame grew, he received many honors, including a
doctor's degree from Oxford in 1832, at which time he was
presented to King William IV.
• For this occasion he had to wear the famous scarlet regalia
of Oxford, which fortunately looked gray to his color-blind
eyes and therefore was acceptable to him as an orthodox
Quaker.
• In 1837 he suffered a damaging stroke; the following year
another left him with impaired speech. A final stroke came
on the night of July 26, 1844.