John Dalton

... And The Development Of The Atom

John Dalton's Background

Dalton was born on September 6, 1766 in Eaglesfield, England. His family was extremely poor. Dalton became a teacher when he was 12 years old. He accepted a teaching job at Quaker University in 1792 when he was 26 years old. He began performing scientific lectures by the early 1820s. Dalton was influenced by his neighbor, Elihu Robinson who explained the latest scientific advances to Dalton.


Atomic Theory

Dalton developed the atomic theory which states that matter is composed of discrete units called atoms. To develop this theory, he studied ancient Greek philosophical concepts and expanded/experimented off of that.

Color Blindness

Dalton was the first person to identify the scientific causes of color blindness. He explained that color blindness is most commonly caused genetically by mutations on the X-chromosome. Other causes are brain damage, degenerative diseases in the eye, or a deficiency in Vitamin A.


Dalton discovered that atoms in each element are identical in size and weight which is the basic concept on which the modern periodic table is based.

Theories About The Atoms Expressed In His Book

1. All matter consists of tiny indivisible particles which he called atoms.

2. All atoms that weighed the same are exactly alike, but atoms of different elements are different.

3. Atoms are unchangeable.

4. Atoms of elements can combine to form compound atoms.

5. In chemical reactions, atoms are neither created nor destroyed, but are only rearranged.

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John Dalton Biography


"John Dalton." Scientists: Their Lives and Works. Gale, 2006. Biography in Context. Web. 21 Nov. 2014.

"Atomic theory." World of Biology. Gale, 2006. Biography in Context. Web. 1 Dec. 2014.