Atomic theory

1808

Atomic theory

The book of science

Tom Sharp

John Dalton physics

Atomic theory

Notation

Symbols

Before we had atomic force microscopes, the existence of atoms and molecules had to be deduced from chemical experiments.

Dalton was the first to assemble the evidence into a complete theory, and the first to prepare a table of the atomic weights of known elements and molecules. As a poet, I am impressed that he invented an alphabet to symbolize the elements and molecules. These are more interesting and artistic than the two-letter chemical symbols based on the Greek that we use today.

My editorial insertion is the parenthetical “(by chemical processes)” in the list of Dalton’s claims, since we know now that an atom may be destroyed.

Around 1787, Dalton rediscovered George Hadley’s theory about trade winds. In 1801 he published a book on English grammar. Dalton suffered a less common form of color-blindness, deuteranopia, and was the first to describe and explain color blindness, proposing that it was due to a discoloration of the liquid medium of the eyeball, which was wrong. In his honor color blindness is sometimes called Daltonism, and the unit of atomic mass the dalton.

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