Timeline of Matter (by Harnake Reehal)

Timeline created by stemnerd
  • Period:
    -500 BCE
    to

    Timeline of Models of Matter

  • -450 BCE

    Empedocles

    Empedocles
    Empedocles was a Greek philosopher who believed that all matter was made up of mixtures of and ratios between the "elements": earth, water, fire and air. He called his model the "four-element model". Through his experiments, he found that although air is invisible, it takes up space and is some form of matter and not just "nothing". His discoveries and his model were important because he gave the idea that matter is composed of four elements and that air is some form of matter (a substance).
  • -400 BCE

    Democritus

    Democritus
    Democritus was a Greek philosopher who believed that all matter was composed of small particles (atoms) which are indivisible. He called them "atomos". He believed that different elements had a different and unique type of atoms. He experimented with breaking down a seashell until it was a powder. His ideas were rejected by influential figures and ignored by society. His discoveries were important because he introduced the idea of spherical small particles (atoms) that make up matter.
  • -350 BCE

    Aristotle (advice for importance)

    Aristotle (advice for importance)
    Aristotle rejected Democritus' idea of atoms because he thought that it didn't make sense. He instead believed in Empedocles' four-element model and that all substances and matter were made up of a mixture of earth, water, fire and air. He did not do any experiments to prove his beliefs, he simply believed in the four-element model. Because of his influence, many people accepted the four-element model of matter. He caused the ideas of atoms to be ignored for almost two millennia.
  • 500

    Many Alchemists (500-1600 A.D.)

    Many Alchemists (500-1600 A.D.)
    Alchemists believed that they could create gold out of cheap metals and performed but failed many experiments to prove it. They created symbols for substances (elements and compounds). Alchemists innovated equipment and tools for the science laboratories such as filters, beakers, etc. They discovered many new substances yet they still believed in the four-element model. Their work was important as they created laboratory equipment, chemical symbols and the theory of the composition of metals.
  • Robert Boyle

    Robert Boyle
    Robert Boyle didn't accept the four-element model. After his experiments with gases, he concluded that air is a mixture and not an element. He believed that the only way to explain his results was with the idea of small particles (atoms). He defined elements as pure substances that cannot be broken down any further. His work was important because he proved that air is a mixture and not a pure substance and he created the definition for an "element".
  • Joseph Priestley (late 1700s)

    Joseph Priestley (late 1700s)
    Joseph Priestley was an English scientist. He became the first to separate and contain as well as discover a gas which is now known as the element oxygen. He experimented with mercury oxide and discovered oxygen as a result of this experiment. He also found that plants and trees produce oxygen through his other experiments. His work was important because he discovered the element oxygen, where it can be produced and he described some of its properties.
  • Henry Cavendish (late 1700s)

    Henry Cavendish (late 1700s)
    Henry Cavendish discovered a gas that is now known as the element "hydrogen" by mixing metals with acids and producing a light and flammable gas. He didn't know that he discovered the element hydrogen. He also experimented with oxygen (Priestley's gas) and his gas (hydrogen) by burning his gas in a jar with oxygen. He proved that water isn't a pure substance since it was the result of his experiment. His work was important because he discovered hydrogen and proved that water wasn't an element.
  • Antoine Lavoisier (late 1700s)

    Antoine Lavoisier (late 1700s)
    Antoine Lavoisier experimented with Priestly's gas and discovered that it was an element and he named it "oxygen". He also discovered that air was a mixture of at least two gases and one of them had to be oxygen. Lavoisier found that oxygen was a very important part of combustion as combustion required oxygen. His work was important because he named the element oxygen, he found that oxygen was important in combustion and that air was a mixture of gases.
  • John Dalton

    John Dalton
    John Dalton created a theory of why elements are different from each other and non-elements. He created an atomic model that states:
    - All matter is made of very small particles called atoms
    - Elements have their own unique atom and mass
    - Compounds are when atoms from different elements bond to form molecules
    - Atoms are indestructible, uncreatable and are indivisible in chemical changes
    He created a new idea of atoms and their nature/structure as well as why elements differ from each other.
  • Michael Faraday

  • Hantaro Nagaoka (1903-1904)

  • J.J. Thomson

  • Robert Millikan (1909-1910)

  • Ernest Rutherford

  • Niels Bohr