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2000 BCE
Alchemy
Alchemy dates back to Egypt and Babilonia 2000 years BCE. Alchemy is the old study and philosophy of how change substances into other substances A common practice was attempting to change common metals into gold Alchemy died off in the 17 and 18 centuries mostly because of scientists at that time that were making discoveries (Isaac Newton) that were too much for Alchemy to keep up with -
490 BCE
Empedocles
Empedocles proposed that everything was made out of one or a combination of 4 elements
- fire, water, air and earth
- it is remarkable that he tried to simplify all matter into elements, perhaps an early version of our current elements. -
460 BCE
Democritus
- Democritus is commonly known as the "father of science" for all his discoveries that the universe is made up of tiny atoms.
- Here are some of the discoveries or theories made by him:
- Everything is composed of “atoms”, which are physically, but not geometrically, indivisible
- Between atoms, there lies empty space
- Atoms are indestructible
- Atoms have always been, and always will be, in motion
- There are an infinite number of atoms, and kinds of atoms, which differ in shape, and size.
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Dalton
Was born in 1766 in Cumberland England and started school at age 12 in his local school. Dalton claimed that the forces of repulsion thought to cause pressure acted only between atoms of the same kind and so the atoms were indeed different in weight and “complexity.” He proceeded to calculate atomic weights from percentage compositions of compounds, using a special system to determine the atomic structure of each compound. he proposed his theories in papers (1808–1827). -
Thomson
Thomson's experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. He discovered the electron by experimenting with a Crookes, or cathode ray, tube. He demonstrated that cathode rays were negatively charged. In addition, he also studied positively charged particles in neon gas. Thomson realized that the accepted model of an atom did not account for negatively or positively charged particles. -
Planck
Max Planck was a German physicist, he is best known as the originator of the quantum theory of energy for which he was awarded the Nobel Prize in 1918. His work contributed significantly to the understanding of atomic and subatomic processes. Einstein demonstrated that electromagnetic radiation including light, has the characteristics of both a wave and, consistent with Planck's theory, a particle. These particles were later called photons. Bohr used it to create a more accurate atom diagram -
Hantaro Nagoka
Japanese physicist Nagaoka Hantaro in particular developed the “Saturnian” system in 1904. The atom, as postulated in this model, was inherently unstable because, by radiating continuously, the electron would gradually lose energy and spiral into the nucleus. -
Marie Sklodowska Curie
Curie was a pioneer in researching radioactivity, winning the Nobel Prize in Physics in 1903 and Chemistry in 1911. Curie never worked on the Manhattan Project, but her contributions to the study of radium and radiation were instrumental to the future development of the atomic bomb. discovered the elements polonium and radium. Prohibited from higher education in her native Poland (then controlled by Russia), she moved to Paris in 1891 and studied at the Sorbonne. -
Rutherford
In 1911, he was the first to discover that atoms have a small charged nucleus surrounded by largely empty space, and are circled by tiny electrons He was also credited with the discovery of the proton in 1919, and predicted the existence of the neutron and was awarded the Nobel Prize in Chemistry in 1908 “for his investigations into the disintegration of the elements, and the chemistry of radioactive substances”. -
Bohr
His theory of atomic structure in which a hydrogen atom consist of a proton as nucleus, with only one single electron moving in distinct circular orbits around it, each orbit corresponding to a specific quantized energy state: the theory was extended to other atoms. His theory was proposed in 1903 -
Shrodinger
Erwin Schrödinger showed that the quantization of the hydrogen atom’s energy levels that appeared in Bohr’s atomic model could be calculated from his equation, which describes how the wave function of a quantum mechanical system evolves his most famous experiment became known as “Schrödinger’s cat”, A cat is in a box with a vial of poison. The vial breaks if an atom inside the box decays. The atom is superposed in decay and non-decay states until it is observed, and so it is dead and alive -
Chadwick
He was an English physicist and winner of the 1935 Nobel Prize in Physics. Chadwick is best known for his discovery of the neutron in 1932. A neutron is a particle with no electric charge that, that along with a proton makes up for the nucleus Throughout the war, Chadwick drafted agreements to supply uranium for the Manhattan Project. He also observed the first atomic explosion known as the Trinity test. Because of his insistence Britain was allowed to be present at the bombing of Nagasaki. -
Louis De Broglie
Louis de Broglie was an eminent French physicist. He gained worldwide acclaim for his work on quantum theory. In his 1924 thesis he discovered the wave nature of electrons and suggested that all matter have wave properties. He won the 1929 Nobel Prize for Physics. Broglie’s theory resolved and offered an explanation to a question that was brought up by calculations of the motion of electrons within the atom. -
satyendra nath bose
Satyendra Nath Bose is best known for giving the concepts of 'Boson', which refers to one of the two classes of particles. His work in quantum physics was further developed by Albert Einstein which laid the foundation for Bose-Einstein statistics and the theory of the Bose-Einstein condensate. -
Irene Curie
The Joliot-Curies won the 1935 Nobel Prize in Chemistry for their artificial creation of new radioactive elements by bombardment of alpha particles (helium nuclei, He2+) on various light elements. In 1938 her research on the action of neutrons on the heavy elements, was an important step in the discovery of uranium fission -
Ronald Gillespie
Gillespie has done extensive work on expanding the idea of the Valence Shell Electron Pair Repulsion (VSEPR) model of Molecular Geometry In 2007 he was awarded the Order of Canada. Gillespie has also done extensive work on interpreting the covalent radius of fluorine. -
Richard F.W.
Richard F. W. Bader was a Canadian quantum chemist, noted for his work on the Atoms in molecules theory. His theory attempts to establish a physical basis for many of the working concepts of chemistry, such as atoms in molecules and bonding, in terms of the topology of the electron density function in three-dimensional space
