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  ...the idea of the atom. Democritus pounded up materials in his pestle and mortar until he reduced them to smaller and smaller particles which he called ATOMA.
Fun Fact:
ATOMA: Greek for INDIVISIBLE - 
  
  ...that all matter was made up of tiny spheres that were able to bounce around with perfect elasticity and called them ATOMS.
Fun Fact:
ATOM-Made up of protons, neutrons and electrons. - 
  
  ...atoms could sometimes eject a far smaller negative particle which he called an ELECTRON.
Fun Fact
ELECTRON: Float around the nucleus. Are negativly charged. - 
  
  ...the idea that an atom was made up of electrons scattered unevenly within an elastic sphere surrounded by a soup of positive charge to balance the electon's charge like PLUM PUDDING.
Fun Fact:
PLUM PUDDING MODEL: This idea looks like plums surrounded by pudding. - 
  
  Geiger and Marsden carrying out their famous experiment. They fired helium nuclei at a piece of gold foil which was only a few atoms thick. They found that although most of them passed through, about one in ten thousand hit.
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  fired helium nuclei at a piece of gold foil which was only a few atoms thick. They found that although most of them passed through, about one in ten thousand hit during their famous experiment.
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  ...Rutherford's idea by adding that the electons were in orbits. Rather like planets orbiting the sun. With each orbit only able to contain a set number of electrons.
Fun Fact:
NIELS BOHR studied under Rutherford at the Victoria University in Manchester.