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J J Thomson By Jada Loren

Published on Nov 18, 2015

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PRESENTATION OUTLINE

J. J THOMOS

BY JADA LOREN FORD

J.J THOMSON

  • Full name: Joseph John Thomson
  • Born: December 18, 1856, Manchester, United Kingdom
  • Colleges he went to: University of Manchester
  • Victoria University of Manchester, Cambridge, University of Cambridge
  • Main focus: the plum pudding experiment

MAIN FOCUS AND HIS THEORY

  • Thomson had discovered that atoms are composite objects
  • that the negatively charged electrons within the atom were very small compared to the entire atom.
  • Negatively-charged is the plum
  • positively-charged pudding.
  • Plum pudding

WHY DID THE PLUM PUDDING MODEL EXPERIMENT FAIL?

  • In Thomson’s Plum Pudding Model each atom was a sphere filled with a positively charged fluid.
  • The model could not predict why the atoms absorbed and emitted spectral lines.
  • The real destruction to the model came from experiments showing that atoms have nuclei

WHAT WAS HIS MAIN EXPERIMENTAL DESIGN

PLUM PUDDING DESIGN AND WHY IT FAILED

THE EVIDENCE IN THE PLUM PUDDING EXPERIMENT

  • The evidence was not factual
  • A scientist named Rutherford designed an experiment to test the plum pudding model.
  • the components of the atom had been discovered. The atom consisted of particles called protons and electrons. However, it was not clear how these protons and electrons were arranged within the atom. J.J. Thomson suggested the"plum" model. In the model the electrons and protons are uniformly mixed throughout the atom.
  • Rutherford tested Thomson's hypothesis by devising his "gold foil" experiment. Rutherford reasoned that if Thomson's model was correct then the mass of the atom was spread out throughout the atom.
  • if he shot high velocity helium nuclei at an atom then there would be very little to deflect the helium nuclei. He decided to test this with a thin film of gold atoms.

PART TWO TO #6

  • As expected, most alpha particles went right through the gold foil but to his surprise a few helium nuclei rebounded directly backwards.
  • These deflections were not consistent with Thomson's model. Rutherford was forced to discard the Plum Pudding model

HOW WAS RUTHFORD THEORY DIFFERENT FROM THOMSONS

  • The difference was that Rutherford shot electrons at a thin gold foil and some electrons actually came backwards. He suggested that the atom was largely empty space (because few electrons deviated) with a small, dense, positively charged nucleus.

JJ THOMSON NEW THEORY

  • Their wasn't any new theory.

THATS IT =)

BY JADA LOREN FORD