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400 BCE
Democritus
At 60 years old, Democritus was known for when he made the discovery of central figure in development of atomic theory of the universe. Democritus rejected atomism in generation and corruption; He thought of this theory that atoms were uniform, solid, hard, uncompressed, indestructible, and moved in big groups of numbers through empty space until they were stopped. He also thought that shape and size determined various properties of matter. -
330 BCE
Aristotle
Aristotle was a teacher that found his own school in Athens in Lyceum. He was a Greek philosopher and a polymath during the classical period. Aristotle made a pioneering contribution to all the fields of philosophy and science. -
5 BCE
Plato
Plato was a student of Socrates and then later taught Aristotle. He found a academic program later in the his years; Aristotle soon became famous from his theory of forms known by pure reason and presented a solution to a problem of universal as Platonism. -
The Alchemists
The alchemists is an idea of individuals that should live in singular pursuit of their individuals dreams. An alchemists is a person who transforms things to the better; it has self-development, and the value of life, it also purifies, mature perfect and certain materials. -
John Dalton
John Dalton was born in 1766 and died in 1844, he was an English chemist, a physicist, and meteorologist; He's best known for the atomic theory. John Dalton was colorblind, which he researched about colorblindness. Many languages named colorblindness Daltonism, after his last name. -
Lavoisier
Antoine Laurent de Lavoisier was a French noble man and chemist; he was born in 1743 and died in 1794. Lavoisier was known as "The father of modern chemistry." He discovered the role of oxygen plays in combustion and respiration, and proved the law of conservation in 1778. He also helped make the metric system and made the first list of elements; He named hydrogen. -
Newland Law of Octaves
Newlands Law of Octaves was created by a English chemist in 1865, his name was John (J.A.R.) Newlands. Newland created this because it was an early classification for elements in the periodic order. When the elements are arranged in the right order, an increasing atomic mass in every 8 elements are similar. -
Mendeleev's Pd. Table
Mendeleev called the periodic table the periodic system. He discovered the periodic table while attempting to organize the elements. How the table was developed based on the atomic weight, elements with similar property's were put under each other. Mendeleev left gaps for new discoveries. -
Photoelectric Effect
The Photoelectric effect is a phenomenon that is electrically Charged particle, and released from/within material when it absorbs electromagnetic radiation. It has an effect that is often defined as a ejection of electrons from a metal plate when light has fallen on it. -
Discovery of Radioactivity
The Discovery of Radioactivity was in 1896 by Henri Becquerel. This discovery was one of the most well-known accidents of physics. A strong radioactive elements called polonium and radium occur in naturally in uranium materials. Radioactivity is an emission of ionizing radiation or particles by spontaneous atomic nuclei.(an act of emitting radiation spontaneously) -
Discovery of the Electron
J.J. Thompson was the person who discovered the electron by experimenting Crookes and/or cathode rays. He found out that a cathode ray had a negative charge. -
Rutherford's Gold Foil Experiment
Rutherford's gold foil experiment was a piece of gold foil that was hit with an alpha particle; That had a positive charge. Most alpha particles just went straight through, that also showed that gold atoms mostly empty space. -
Planck's Quantum Theory of Light
The Planck's quantum theory of light tells you that a light bulb filaments should be heated to a temperature of 3,200 kelvin; It ensures that most energy is emitted to visible waves. -
Plum Pudding Model
J.J. Thompson discovered the Plum Pudding Model in 1904; The model has a negative charge and has electrons imbedded which have a positive charge "soup." The Plum Pudding Model represents important steps in the development of the atomic theory, and incorporates the new discoveries. It predicts majority of alpha particles that would go straight through sheet gold. -
Charge of the Electron
An electron has a negative charge; it is the lightest stable subtonic particle. the electron carries a negative charge 1.602176634 x10 -19, and the mass of an electron is 9.1093837015 x10 -31 kg. -
Robert Millikan
A major discovery that Robert Millikan made was the accurate of determination of charge carried in an electron, how he figured it out was by using The Elegant also called the "falling drop method." It proved that electrons have the same quantity and are all consistent; This discovery demonstrated the atomic structure of electricity. -
Bohr's Planetary Model
Neils Bohr created the Bohr's Planetary Model in England, 1913 when he discovered the glowing, hot hydrogen that gives off light. Why this model is called Boher's planetary is because the orbit of the electrons look similar to planets orbiting around the sun, electrons close a circle around the nucleus to give specific paths called orbits. Electrons have a small positive charge that define a circular orbit in the nucleus, which they are only able to do certain orbits around the nucleus. -
Moseley's Atomic Numbers
Moseley published a paper that conclude atomic numbers that have positive charges in a atomic nucleus. He stated the unknown elements that are 43, 61, and 75 that are in-between aluminum and gold and he said that their are a total of 4 elements. Moseley observed and measured a x-ray spectra of many various chemical elements diffraction in crystals. -
Discovery of the Proton
Ernest Rutherford was the person who discovered the proton, but also the proton dates back to 1815 by a English chemist William Prout. Rutherford proved that a nucleus of the hydrogen atom is presented in a nuclei of other atoms in 1917. -
Schrodinger Equation
The Schrodinger equation yields a function of a particle in energy potential. It is a linear particle that is a differential equation that governs a wave function of Quntum-Mechanial systems. The equation is a key discovery that is significant landmark in the development of a subject. -
Heisenberg Uncertainty Principle
A German physics and Heisenberg came up with the uncertainty principle, and it states that it can't know both a position or speed of a particle, like a proton or a electron with such accuracy. This principle is impossible to measure or calculate the exact position or the moment of an object. -
Discovery of the Neutron
James Chadwick was scientist who found the neutron; A neutron was a newly found uncharged particle. The neutron was a extraordinary development that atomic physics in the 20th century.
