Searching for the Atom's Structure

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Around 1900, people thought atoms were permeable spheres. In 1909, Rutherford, supervising Geiger and Marsden, tested the validity of this theory in his now-famous gold-foil experiment.

The experiment was quite simple: a radioactive source would shoot a stream of alpha particles at a very thin gold foil (alpha particles have very little mass compared to gold atoms.) Surrounding the gold foil was a screen covered with zinc sulfide so that the alpha particles hitting the screen would leave microscopic spots in the zinc sulfide.