It seems to us modern people that the atom is just general knowledge that everyone is taught about in their middle school physical science class. The Idea of the atom hasn’t always been around, until, surprisingly in 4th century B.C. Greek Philosopher Democritus asked himself this question, “If you break a piece of matter in half, and then break it in half again, how many breaks will you have to make before you can break it no further?” The only reasoning he could gather is that eventually you can no longer break the matter right? There must be an end right? He called this ending unit an atom – a solid indivisible sphere of matter.
Democritus’ theory was later dismissed by a few respected Greek philosophers and was blind to the world until the 1800s where the main principals fathered the atom’s physical make-up. In 1897, English Physicist J.J. Thomson introduced the first atomic model known as the “Raisins in the Pudding” model.
Thomson discovered that the atom did in fact exist after he discovered electrons through experimentation. He knew the electrons were negatively charged and could not exist by themselves so he claimed the matter (wood, metal, gold, etc.) had to be positively charged. Thomson’s model was accepted until 1909. Ernest Rutherford blew his own mind as he decided to test the existence of electrons with the newly introduced technology of alpha rays (positively charged photon beams). Rutherford’s experiment was simple: shine the beam through a piece of gold foil and watch the beam refract off the electrons on the nucleus of the gold and scatter on the backside. His hypothesis proved false as the beam did not have direct paths out the back end but actually refracted in all different directions even back at him. He concluded that the electrons did not in fact reside on the nucleus but rather floated around it. The problem he faced then was, “Well what kept the nucleus from pulling apart?” He then claimed there had to be some uncharged particle in the nucleus to help cancel out proton charge. He called these neutrons – later proven to exist by Physicist Planck in 1930.
Just 4 years after Rutherford’s model was active Neil Bohr a Danish Mathematician proposed a more uniformed design building off Rutherford’s Model. It consisted of a nucleus with levels or “orbital paths” that the electrons followed - similar to planets orbiting the sun. Each energy level could hold a certain number of electrons and once that threshold was broken that level was said to be “excited” and the electron must move to the next level up. Bohr’s model is still accepted today and used in chemistry to follow changes in ionized atoms. His model is not the contemporary model. The last model came to existence in the 1930’s and 1940’s as scientist acknowledged that electrons follow no specific path as stated by Bohr, but instead can be any one place in the atom at anytime. This is represented by the “Electron Cloud Model.”
It is my admiration for such physical scientist that inspire me to have the want to invent and discover new things. I like to see something so small as an atom and later the discovery of quarks an even smaller to become something as vast as planetary objects or galaxies. I wanted this to illustrate mostly how ideas can mature overtime. And we should never as people stop looking for an explanation even if we think we might know a "definite" truth - we don't. A recent event I hated to see go was the dismissal of NASA's space program. Democritus' Model
Democritus’ theory was later dismissed by a few respected Greek philosophers and was blind to the world until the 1800s where the main principals fathered the atom’s physical make-up. In 1897, English Physicist J.J. Thomson introduced the first atomic model known as the “Raisins in the Pudding” model.
Thomson's Model
Thomson discovered that the atom did in fact exist after he discovered electrons through experimentation. He knew the electrons were negatively charged and could not exist by themselves so he claimed the matter (wood, metal, gold, etc.) had to be positively charged. Thomson’s model was accepted until 1909. Ernest Rutherford blew his own mind as he decided to test the existence of electrons with the newly introduced technology of alpha rays (positively charged photon beams). Rutherford’s experiment was simple: shine the beam through a piece of gold foil and watch the beam refract off the electrons on the nucleus of the gold and scatter on the backside. His hypothesis proved false as the beam did not have direct paths out the back end but actually refracted in all different directions even back at him. He concluded that the electrons did not in fact reside on the nucleus but rather floated around it. The problem he faced then was, “Well what kept the nucleus from pulling apart?” He then claimed there had to be some uncharged particle in the nucleus to help cancel out proton charge. He called these neutrons – later proven to exist by Physicist Planck in 1930.
Rutherford's New Model
Just 4 years after Rutherford’s model was active Neil Bohr a Danish Mathematician proposed a more uniformed design building off Rutherford’s Model. It consisted of a nucleus with levels or “orbital paths” that the electrons followed - similar to planets orbiting the sun. Each energy level could hold a certain number of electrons and once that threshold was broken that level was said to be “excited” and the electron must move to the next level up. Bohr’s model is still accepted today and used in chemistry to follow changes in ionized atoms. His model is not the contemporary model. The last model came to existence in the 1930’s and 1940’s as scientist acknowledged that electrons follow no specific path as stated by Bohr, but instead can be any one place in the atom at anytime. This is represented by the “Electron Cloud Model.”
Bohr's Model
Study By Jay Giles
I disagree with the statement "that the atom is just general knowledge that everyone is taught about in their middle school". Although that statement is true for most citizens of developed civilizations such as those who live in nations such as the USA or Germany. It is not the case world over. Take the expamle of modern day people in some nations of Africawhere there is no such thing as univefsal middle schools. Use for instance one of children who labor for blood diamonds in Africa. I doubt if such a child has ever heard, nor will ever hear of the atom. And I especially disagree that the Greek philosopher Democritus asked his infamous question in 460 bce. I state this due to his birth in Thrace at Abdera being that very same year. Democritus lived from 460 bce to 370 bce.
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