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460
Democritus (460-370 BC)
Developed of the theory of Atoms. Says
Matter is divisible into parts, and such part again into smaller parts. -
Dalton,John (1766-1844)
Dalton is best known for his contributions to the atomic theory in of matter. Dalton refined the theory by suggesting that each chemical element consists of a Single type of atom.Dalton arranged all of the known chemical elements in a table according to atomic weight . Dalton also devised a system of chemical symbols to use in formulas. He first stated the law of partial pressures. -
Wilhelm Conrad Röntgen (1845-1923)
German physicist who was a recipient of the first Nobel Prize for Physics, in 1901, for his discovery of X-rays, which heralded the age of modern physics and revolutionized diagnostic medicine.Wilhelm Conrad Röntgen was the first scientist to observe and record X-rays, first finding them on November 8, 1895. -
Thomson, Sir Joseph John (1856-1940)
British physicist who discovered the electron, a fundamental atomic particle. Thomson's discovery revolutionized scientific understanding of the atom. His work proved that the atom could indeed be broken down into smaller particles.Thomson discovered the first isotopes of a chemical element, specifically of the element neon. -
Curie, Pierre (1859-1906)
Until the mid-1890s most of Curie’s research was on magnetism and on crystals.. he along with his wife discovered and named the radioactive elements polonium and radium. -
Curie, Marie, née Maria Sklodowska (1867-1934)
Best known for her work on radioactivity, with her husband Pierre.In 1898 she discovered that such rays were emitted in unexpected strength by the uranium-containing mineral pitchblende, for which she coined the term “radioactive”. she confirmed the existence of new elements, polonium and radium -
Bohr, Niels Henrik David (1885-1962)
Bohr developed a theory relating quantum numbers to large systems that follow classical laws, and made other major contributions to theoretical physics. His work helped lead to the concept that electrons exist in shells and that the electrons in the outermost shell determine an atom's chemical properties.He later demonstrated that uranium-235 is the particular isotope of uranium that undergoes nuclear fission. -
Chadwick, Sir James (1891-1974)
British physicist and Nobel laureate, who is best known for his discovery in 1932 of one of the fundamental particles of matter, the neutron, a discovery that led directly to nuclear fission and the atomic bomb. -
De Broglie, Louis Victor (1892-1987)
His work greatly advanced the early understanding of quantum theory, the study of the parts of the atom and their behavior. In 1924, existing quantum theory stated that light waves sometimes behave like particles. -
Werner Karl Heisenberg(1901 - 1976)
he had a theory of quantum mechanics published in 1925, when he was only 23 years old. For this theory and the applications of it which resulted especially in the discovery of allotropic forms of hydrogen, -
ROBERTANDREWSMILLIKAN (1868-1953)
Researched on the polarization of light emitted by incandescent surfaces.His earliest major success was the accurate determination of the charge carried by an electron.Next, he verified experimentally Einstein's all-important photoelectric equation.The discovery of his law of motion of a particle falling towards the earth after entering the earth's atmosphere, together with his other investigations on electrical phenomena, ultimately led him to his significant studies of cosmic radiation. -
Aristotle (384-322 B.C )
He examined the structure of plants and animals and observed the behavior of animals. He also classified living things in groups according to their common traits rather than their usefulness to humans.Aristotle's influence on the modern world is the large number of words in modern languages that can be traced back to his teaching and writings. For example, the terms of grammar, subject and predicate, come from Aristotle.These include matter, energy, potential, cause, genus, species, etc.
