RUTHERFORD ALPHA PARTICLE SCATTERING EXPERIMENT AND HIS MODEL OF AN ATOM
- 1. RUTHERFORD ALPHA PARTICLE SCATTERING EXPERIMENT AND HIS MODEL OF AN ATOM NAME : MOHIT MANGLA CLASS : IX-SCHOLARS SCHOOL : DELHI PUBLIC SCHOOL BALLABGARH
- 2. ERNEST RUTHERFORD (1871-1937) Ernest Rutherford, first known as Baron Rutherford (30 August 1871 - 19 October 1937) was a New Zealand born British chemist and physicist who became known as the father of nuclear physics. He is considered the greatest experimentalist since Michael Faraday (1791- 1867). In early work he discovered the concept of radioactive half-life, proved that radioactivity involved the transmutation of one chemical element to another, and also differentiate and named alpha and beta radiation.
- 3. PLACE AT WHICH RUTHERFOD DONE THIS RADIOACTIVE EXPERIMENT This work was done at McGill university in Canada. It is the basis for the Nobel prize in chemistry. He was awarder in 1908 “for his investigations into the disintegration of the elements, and the chemistry of radioactive substances. (Structure of an Atom)
- 4. ABOUT THE EXPERIMENT Rutherford scattering experiment is a phenomenon in physics that was explained by Ernest Rutherford in 1911, which led to the development of the Rutherford model (planetary model) of the atom, and eventually to the Bohr Model. It is now exploited by the materials analytical technique Rutherford Backscattering . Rutherford scattering is also sometime referred to as Coulomb scattering because it relies only upon static electric forces, and the minimal distance between particles is set only by this potential. The classical Rutherford Scattering of alpha particles against gold nuclei is an example off “elastic scattering” because the energy and velocity of the outgoing scattered particle is the same as that with which it began.
- 5. Rutherford also later analyzed inelastic scattering when he projected alpha particles against hydrogen nuclei (protons) ; however this latter process is not referred to as "Rutherford scattering", although Rutherford was first to observe it. At the end of such processes, non-coulombic forces come into play. These forces, and also energy gained from the scattering particle by the lighter target, change the scattering results in fundamental ways which suggest structural information about the target. A similar process probed the insides of nuclei in the 1960s, and is called deep inelastic scattering.
- 6. APPARATUS ¡ Gold Foil ¡ Lead Block Shield ¡ Zinc Sulphide Screen ¡ Source of Alpha Particles
- 7. PROCEDURE A narrow beam of alpha particles was aimed at a thin sheet of gold foil. A zinc sulfide coated screen surrounding the gold foil produced a flash of light when struck by an alpha particle. By noting where the flashes occurred, the scientists could determine if the atoms in the gold foil deflected the alpha particles.
- 8. OBSERVATION § Most of the particles went straight through the gold foil. § Several particles were deflected straight back toward the source ! § a few particles were deflected at large angles.
- 10. CONCLUSION As a result of his observations, Rutherford suggested that the atom had a positively charged centre which contained most of the mass. He called the heavy positively charged Centre the nucleus. He went on to suggest that the nucleus was surrounded by orbiting electrons required for electrical.