The History Of Matter

Timeline created by olivia.verge
  • -450 BCE

    Four Elements

    Four Elements
    Scientist: Empedocles
    Theory/Discovery: Everything is made up of the four elements; earth, air, water, fire
    Details: The elements were thought to each share characteristics; dry, wet, hot and cold. Empedocles check this theory and determined that since air takes up space, it is a form of matter (click on photos to enlarge)
  • -400 BCE

    The Atom

    The Atom
    Scientist: Democritus
    Theory/Discovery: All matter can be continually divided until a singe particle is reached. The particle was named "the atom" as atom means "cannot be cut"
    Details: Democritus then proposed that atoms are
    -Of different sizes
    -In constant motion
    -Separated by empty spaces
  • -350 BCE

    Belief of the Four Elements

    Belief of the Four Elements
    Scientist: Aristotle
    Theory/Discovery: The four elements
    Details: Aristotle believed in Empedocles's four elements theory and because of his influence and writings, lead the world to believe as well for almost 2000 years.
  • Elements

    Scientist: Robert Boyle
    Theory/Discovery: Elements are simple unmitigated bodies
    Details: Robert Boyle rejected the four-element theory and came up with his own theory, known as the modern definition of elements. Boyle also believed that air was a mixture and not an element
  • Oxygen as an Element

    Oxygen as an Element
    Scientist: Joseph Priestley & Antoine Lavoisier
    Theory/Discovery: Air is a mixture
    Details: Joseph Priestley isolated oxygen but then Antoine Lavoisier realized that it was an element. He then experimented to find that air was a mixture of oxygen and at least one other gas
  • Hydrogen

    Scientist: Henry Cavendish
    Theory/Discovery: Hydrogen and that water is a mixture
    Details: Henry Cavendish mixed metal with acid and created hydrogen. He discovered that hydrogen would burn in oxygen and produce water
  • Billiard Ball Model (Atomic Model)

    Billiard Ball Model (Atomic Model)
    Scientist: John Dalton
    Theory/Discovery: Billard ball model
    Details: John Dalton's atomic model stated that
    -All matter is made of atoms which are particles too small to see
    -Each element has its own kind of atom with its own mass
    -Compounds are created when atoms of different elements link to form molecules
    -Atoms can not be created nor destroyed or subdivided in chemical changes
  • Ions

    Scientist: Micheal Faraday
    Theory/Discovery: Electric currents can cause chemical changes in some compounds and solutions
    Details: The atoms gain the electric charges and form charged atoms that are called "Ions". Micheal Faraday modified Dalton's billiard ball model, concluding that...
    -Matter must contain positive and negative charges
    -Opposite charges attract and like charges repel
    -Atoms combine to form molecules because of electrical attractions between atoms
  • Electron

    Scientist: J.J. Thompson
    Theory/Discovery: Negatively charged particles can be emitted by very hot materials.
    Details: Thompson concluded that the particles emitted must be negatively charged because when he experimented they were attracted to the positive end of the circuit. Thomson theorized that
    -Atoms contain negatively charged electrons
    -Since Atoms are neutral, the rest of the atom is a positively charged sphere
    -Negatively charged electrons are evenly distributed throughout the atom
  • Nucleus

    Scientist: Ernest Rutherford
    Theory: Small positively charged mass in the middle of the atom
    Details: Rutherford tried sending positively charged particles through a thin piece of foil, suspecting that they would go through, but then as some deflected at large angles, he realized they were colliding with a mass in the middle of the atom.
  • Nucleus Cont.

    Nucleus Cont.
    Rutherford concluded that...
    -The center of the atom contains most of the atom's mass, but not much area. The nucleus is what made some of the particles bounce back unexpectedly
    -The nucleus is surrounded by negative electrons
    -Most of the atom is empty
  • Proton

    Scientist: Ernest Rutherford
    Theory/Discovery: Protons in the nucleus
    Details: rutherford found that protons alone could not account for the nucleus' ass and there must be another particle inside. This third particle had the same mass as the proton but was neutral in charge
  • Neutron

    Scientist: James Chadwick
    Theory/Discovery: Particles that could easily penetrate and disintegrate atoms
    Details: Chadwick realized that the particles have zero charges and are neutral and that there are more undetected particles in the atom. Chadwick proposed that
    -Atoms are empty spheres with dense nucleus'
    -The nucleus contains positive protons and neutral particles (neutrons)
    -Negative electrons circle the space around the nucleus
    -A neutral atom has the same number of protons as electrons
  • Period:

    Continuation of the Belief of the Four Elements

    Scientist: Alchemists
    Theory: Metals ripen into gold
    Details: The alchemists tried to grow gold from cheaper metals but had no success. Though failing to grow gold the alchemists came up with the chemical symbols for elements and compounds, and many common lab tools still used today.