Evolving Theories Of Matter

By winterwonderland
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    The Middle Easterns

    The Middle Easterns learned how to change a range of substances to their advantage. They used simple stone tools. This led to production of glass and ceramic material.
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    Early Chemists

    6000 B.C. Gold became highly valued because of it's attractive color and lustre. Copper also became very valued because it could be made into pots, cans, and tools. Later on experimenting with copper led to the creation of bronze.
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    Democritus

    400 B.C. Democritus stated "each type of matter was made up of a different type of atomos." Atomos mean "indivisible." Democritus proposed this word to portray the smallest particles that could not be broken down further.
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    Aristotle

    350 B.C. Aristotle stated "everything was made up of earth, air, fire, and water." Aristotle was well known and greatly respected among people so his hypothesis was preferred over Democrtius'.

  • Robert Boyle

    1660's Robert Boyle experimented with the behaviour of gases. He determined the composition of gases. He also explored with gases under pressure.Boyle had also believed Democritus' theory that matter was made up of tiny particles. He strongly believed that the tiny particles in matter would group together to form individual substances.

  • John Dalton

    1808 John Dalton developed the theory of the compositon of matter. He also announced that matter is made up of elements. Dalton was the first to define an element as a pure substance that contained no other substances. He stated "each element is composed of a particle called an atom." John discovered the Theory of Atomic Structure. His basic description was correct but some of his ideas were later altered

  • J.J. Thomson

    1897 J.J. Thomson was the first person to discover a particle smaller than an atom. He described an atom as "a positively charged sphere in which negatively charged electrons were embedded like raisins in a bun." This is now called the "raisin bun model."

  • Ernest Rutherford

    1907 Ernest Rutherford succeeded for what he did in radioactivity. He led experiments where he shot positively charged particles through thin gold foil. He believed that atoms were aminly empty space through which the positive particles could pass, but at the core was a tiny positively charged centre, called the nucleus.

  • Niels Bohr

    1913 Niels Bohr conceived the theory of an atom. He stated that they move in specific circular orbits, or electron shells, he believed that electrons jump between these shells by gaining or losing energy.

  • James Chadwick

    2011 James Chadwick said that a positively charged nuclues was surrounded by a cloud of electrons.