Learn All About The Philosophers and Scientist That Made The Atomic Theory Possible.
465 B.C
Democritus
Democritus was born at Abdera, about 460 BCE and lived to be 90 years old in 370 BC. During some part of his life he was attended the Pythagoreanism school and studied natural philosophy in Thrace, Thens, Abdera, and Greece. He also was a disciple of Leucippus who was a philosopher who is known to created the first atomic theory. Leucippus's theory stated that the universe is compsed of two elements, atoms and the void in which they exist and move. Democritus later expaned the Lecippus's theory. Democitus stated that atoms cannot be destroyed, they are invisible, they are hmogenous, solids are made of small pointy atoms, liquids are made of large round atoms, oils are made of very fine small atoms that can easily slip past each other, and atoms differ in size, shape, mass positio, temperature, and arrangement. He created this theory in 460 B.C.but created his model in 400 B.C. Even though his model does not consist of protons, neutrons, and elections he is known for making the first atomic model.
January 1st, 350
Aristotle
Aristotle was born in 385 B.C. in Stagira, Greece. He lived and worked almost his entire life in Greece. When he reached the age of 17 he went to a school called the Academy, in Athens, Were he studied under Plato, who was a good role model to him. He later taught at the academy for 20 years. Even though is known in the field of chemistry, he studied a wide variety of science including, logic, philosophy, ethics, physics, biology, psychology, politics, and rhetoric. Also when the atomic theory was invented Aristotle did not believe in it. He believed that all things were made up of fire, water, air and earth. He taught others what he believed in and was so well-known for his teachings that many believed what he taught was true.
January 1st, 1803
John Dalton
John Dalton, born in 1766 and died in 1844, lived to be about 78 years old. Something interesting about him is that his dad was a weaver who owned a small amount of land. The major points to his atomic theory was that, elements are made up of really small particles called atoms, atoms in an element are identical in size, they cannot be divided, created or destroyed, atoms in different elements combine in whole number ratios to form chemical compounds, and in chemical reactions atoms are combined, separated, or rearranged.
January 1st, 1897
J.J. Thomson
J.J. Thomson born in 1856 and died in 1940, was an English physicist. J.J. Thomson discovered the electron in 1897, proposed the plum pudding model of an atom in the year 1904. Thomson discovered the electron by experimenting with a Crookes, or a cathode ray, tube. Thomson realized that the accepted model of an atom did not account for negatively or positively charged particle. Therefore he proposed the plum pudding model, the negative charge representing the raisins and the positive charge representing the dough. Also Thomson was born in Cheetham Hill, England.
1900 Ernest Rutherford
Rutherford was born in Spring Groove New Zealand in August 30, 1871. and was a Physicist. In 1895, as the first research student at the University of Cambridge’s Cavendish Laboratory in London, Rutherford identified a simpler and more commercially viable means of detecting radio waves than had been previously established by German physicist Heinrich Hertz. Thomson studied the effects of X-rays on the conductivity of gases, resulting in a paper about dividing atoms and molecules into ions. While Thomson went on to examine what would later be called an electron, Rutherford took a closer look at ion-producing radiations. Focusing on uranium, Rutherford discovered that placing it near foil resulted in one type of radiation being easily soaked up or blocked, while a different type had no trouble penetrating the same foil. He labeled the two radiation types “alpha” and “beta.” As it turns out, the alpha particle was identical to the nucleus of a helium atom. The beta particle was, in fact, the same as an electron or positron. After this he created his atomic model showing elections moving around the nucleus. This atomic model is known as the plum pudding model. Rutherford left Cambridge in 1902 and took up a professorship at McGill University in Montreal. At McGill in 1903, Rutherford and has colleague Frederick Soddy introduced their disintegration theory of radioactivity, which claimed radioactive energy was emitted from within an atom and that when alpha and beta particles were emitted at the same time, they caused a chemical change across elements. Rutherford and Yale Professor Bertram Borden Boltwood went on to categorize radioactive elements into what they called a “decay series.”
1911 Niels Bohr
Niels Bohr was born October 7, 1885. An interesting fact about Bohr is that he was a student of Rutherford's. In 1913 Bohr developed a new model of the atom. He proposed that electrons are arranged in concentric circular orbits around the nucleus. This model is also known as the solar system model or simply the Bohr model. The model is summarized into four principles: 1. Electrons only occupy certain orbits around the nucleus. 2. Each orbit has an energy associated with it. 3. Energy is absorbed when an electron jumps from a lower one to a higher one and energy is emitted when an electron falls from a higher orbit to a lower orbit. 4. The energy and frequency of light emitted or absorbed can be calculated by using the difference between the two orbital energies.
1927 Schrodinger and Heisenberg
Schrodinger was born in 1887 in Austria. In 1926, Schrodinger took the Bohr model one step further. He used mathematical equations to determine the likelihood of finding an electron in a certain position. This model was known as the quantum atomic model. Something interesting about him was that he had a cat both dead and alive. Heisenberg was born in 1901 in Germany. In 1924, physicists, Göttingen and Copenhagen decided that the quantum atomic model was too old and had to be replaced with something new. After months of struggling he finally had an answer in July of 1925 but the mathematics was so unfamiliar that he didn't know if it made sense. When he gave it to Born, Born realized that the unfamiliar mathematics was related to the mathematics of arrays known as matrices. After it was sent off to publication it was the breakthrough of quantum mechanics. one interesting fact is that Heisenberg gave many lectures in Edinburgh, Bristol and Cambridge.