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= History of Matter...... = = = = = The Unfinished History of the States of Matter Kathryn Leader

The earliest theories of matter were born as early as 492 BCE. Starting with the Greek philosopher, Empedocies. His early theory stated that all objects were composed of only four elements, fire, air, water and earth. This was a fundamental idea in the future development of a theory suggesting the idea of tiny basic units as the bases of all matter.

Another Greek had other ideas. Democritus proposed his own theory with ideas based on two philosophers who came before he did, Lencippus and Anaxagoras. Democritus suggested a theory based on the belief that matter was not able to be endlessly divisible.1 His theory stated that matter was composed of finite units. He named these units “atomos”, which is Greek for “indivisible” or unable to be divided. The atomos according to Democritus were unique to the specific material in which they were found.

Two well-known ancient Greek philosophers, Aristotle and Plato, challenged Democritus. Aristotle built upon the theory originally proposed by Empedocies. However, Aristotle added his own idea to this earlier theory. Aristotle’s theory included the belief that the four core elements could be transformed into each other.

Democritous’s theory was not reconsidered for almost two thousand years. Fast forward to the year 1643. An Italian mathematician, Evangelista Torricelli, discovered that air, due to the property of mass, had weight and could push down on liquid Mercury.2 This scientific breakthrough not only was the birth of the barometer, but also fostered a return to the consideration of physical units composing material.

With a return of the scientific community to this idea, a Swiss mathematician developed a theory explaining how the idea of tiny particles as the bases of matter. Daniel Bernoulli proposed that gases, such as air, were not only made of particles, but that these particles were moving.

In 1773 an English scientist, Joseph Priestley, provided a key piece to the puzzle of matter through his experiments involving the heating of a special stone. It had long been observed that this specific stone, when heated, produced liquid Mercury. However, Priestly also noted that a gas was also produced during the chemical reaction. The gas was observably different than air. It had a new set of properties. As a result of his work, the notion that substances could be broken down and recombined to make different substances with unique properties.

Within a few years a French scientist, Antoine Lavoisier, while working on many of the same problems, named Priestley’s gas Oxygen. The name Oxygen came from the Greek for “maker of acid”. He further observed the production of water during certain reactions and named the thing we call the element Hydrogen. These experiments were the foundation of the Law of Conservation of Mass.

The first modern atomic theory was the work of John Dalton in 1803. Dalton was mentored by John Gough had a significant influence on John Dalton and the important work Dalton did. 3 Dalton was a British scientist, Dalton was able to piece together the various ideas of the scientists that came before him over the course of five years to arrive at his atomic theory proposed in his paper entitled “A New System of Chemical Philosophy”. 4

Sources

1 Capri, A. (2003). Matter: atoms from Democritus to Dalton. Visionlearning, 1. retrieved from http://www.visionlearning.com/library/module_viewer.php?mid=49

2 Leicester, H. M. (1951). The historical background of chemistry. retrieved from http://books.google.com/books?id=aJZVQnqcwv4C&printsec=frontcover&dq=The+historical+background+of+chemistry.&source=bl&ots=E62x3PSnTe&sig=ybPaqDyTpzCcG5kCZ1KREwHDbqE&hl=en&ei=d3UKTLrALcXflgeiyfH_Dg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBwQ6AEwAA#v=onepage&q&f=false

3 Blamire, J. (2002). Science@a Distance. retrieved from http://www.brooklyn.cuny.edu/bc/ahp/FonF/Dalton.html

4Dawson, J. (1808). A New system of chemical philosophy. retrieved from http://web.lemoyne.edu/~giunta/dalton.html