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300
Aristotle
Aristotle was a philosopher who believed you could solve any problem by just thinking about it and that everything was made up of a combination of the four elements. He thought that there was a ginormous size of air everywhere and that no seperate materials existed. -
Period: 300 to
Atom Timeline
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400
Democritis
Democritis was the first to identify the possibility of an atom and came to his conclusion by reasoning rather by science. He thought that things were made up of smaller units and called them "atomos". He wras a Greek philosopher who wrote more then 50 books but they were all destroyed in the 3rd and 5th centuries. -
Isaac Newton
Isaac Newton proposed a mechanical universe with small solid masses in motion, this means that he believed there was microscopic pieces of mass floating everywhere. -
John Dalton
John Dalton is known as the Father of the Atomic Theory. His initial interest was meterology but realized that pressure exerted by gas in a mixture is independent. He believed that all matter is invisible and nondestructable. He taught other chemist the laws of parital pressure and got the Daltons Atomis theory named after him. He is the man who discovered that the weight and complexity of all atoms are different. -
JJ Thomson
JJ Thomson discovered the electron by using the cathode ray. This invention had a tube that when high voltage pressure went through and the atoms hit the outside it would glow. He was able to test how polar the atoms were with this by placing a magnet next to his ray. He also discovered mass ratio and compared the idea of an atom to plum pudding. -
Marie Curie
Marie Curie studied uranium and thorium. She observed their decay and called it radioactivity. -
Robert Millikan
Robert Millikan was known for his Millikan oil drop. The purpose of this experiment was for him to determine the charge of an electron. He measured the quantity of the electron by observing the electron cloud on single water droplets instead of a cloud. In doing this, he provided a value for the electronic charge which gave the correct Rydberg constant. -
Ernest Rutherford
Ernest Rutherford is known for his gold foil experiment. It worked by shooting atoms into a gold foil and seeing where it hit on the circular wall. he belived the atoms would just go straight, However, occasionally the atom was go to the side. This is what led him to realize that there was something in the middle of the atom(the nucleus). Using all the information he gathered he made the first nuclear model of an atom to actually display the nucleus. -
Niels Bohr
Niels Bohr believed that electrons orbit in different levels rather than spiraling into the nucleus. This is called the bohr model and states that the closer the atom is to the nucleus the more energy it releases while the farther away it is the more it absorbs. -
Louis deBroglie
Louis deBroglie is the man who discovered that electrons have properties of both waves and particles. After finding this out they named a waves after him. -
Werner Heisenberg
Werner Heisenberg is known as the founder of quantum mechanics. He determined it was impossible to determine the position and the momentum of a particle at the same time. -
Erwin Schrodinger
Erwin Schrodinger was known for showing mathematically that waves can be used to describe electrons in atoms. He also determined the probablility of electrons in atoms. -
James Chadwick
James Chadwick helped with the development of the nuclear model and discovered the neutron.
