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Demoscritus's Atomic Theory
460 BC - 370 BC
His theory was matter can be divided only at a certain point when only atoms remain. The world is made up of atoms moving continuously. Atoms differ in each other only in size and shape, and different substances with their distinct qualities were made up of different shapes, and positions of the atoms. -
John Dalton's Atomic Theory
Sep. 6 - July 27 1844
Dalton proposeed the theory that all matter made up of induvidual particles called atoms, which cannot be divided.
Experiment:
He noticed that certain gases maintained the same ratios of mixture regardless of amount. These proportions lead him to believe that the ratios remained the same. -
Micheal Faraday's Atomic Theory
He realized that the current undid the coupling of atoms and that the amount of deposited material was directly proportional to the quantity of current flowing through the solution. This idea concluded that electrical forces held atoms together. -
G.J. Stoney's Atomic Theory
Stoney's most important work was the calculation of the magnitude of the "atom of electricity". In 1891, he came up with the term 'electron' to describe the unit of electrical charge.
Experiment: -
J.J. Thomsons Atomic Theory
His theory was atoms are spheres with a positive charge distributed through the atom containing negative charged electrons separetely put into the atom.
Experiment:
Thomson built a cathode ray tube ending in a pair of metal cylinders with a slit in them. These cylinders were in turn connected to an electrometer. -
Marie Curie's Atomic Theory
Curie actively promoted the use of radium to alleviate suffering. She worked with her husband Pierre Curie. -
Ernest Rutherford's Atomic Theory
His theory was the atom having a central positve nucleas surrounded by negative orbiting electrons most of the atom's mass was contained in it's small nucleas and the rest of the atomis empty space.
Experiment:
He tested the plum pudding model. He fired energetic a particles at a foil, and measured the deflection of the particles as they came out the other side. From this he could soak in information about the structure of the foil. -
Niels Bohr's Atomic Theory
Bohr's theory was atoms travel in a stationary orbit powered by their angular movement this is led to the circulation of possible energy for these orbits and that circulation of light occurs when an electron moves at a lower energy orbit.
Experiment:
All of us have heard of the atomic bomb thats what he tried and suceeded to develope. -
James Chadwick's Atomic Theory
James Chadwick found in 1932 a third type of subatomic particle, which he named the neutron. Neutrons help stabilize the protons in the atom's nucleus. Because the nucleus is so tightly packed together, the positively charged protons would tend to repel each other normally. -
Werner Heisenburg Atomic Theory
Heisenberg worked out that particles had a lot more energy over short distances than thought. The relationship he came up with was the position and energy of a particle can only be known to a certain amount. -
Aristotle's Atomic Theory
384 BC - 370 BC
Aristotle’s theory made a great generalization off all matter being made of the four elements fire, water, earth, and air. He also believed that there were four qualities to these elements dryness, hotness, coldness, and moistness. Based on these beliefs fire would hold the characteristics of being dry and hot, water is wet and cold, air is hot and wet, while the earth is dry and cold.
