What was the gold leaf experiment

Purpose for Reading. What was Rutherford's original belief about atomic structure and what wouldhappen during his experiment? What was the original goal of the experiment? What did they actually observe when they ran the experiment? What new ideas came out of the Gold Foil Experiment? He hypothesized that a beam of alpha particles would pass through thin sections of matter largely undeflected.

He believed that some alpha particles would be slightly scattered whenever they encountered electrons. The vacuum is important because any deflection of the alpha particles would only be because of collisions with the gold foil and not due to collisions with air particles. Gold was used because it was the only metal that could be rolled out to be very, very thin without cracking. Since the gold foil was very thin, it was thought that the alpha particles could pass straight through it, or possibly puncture the foil.

The scientists were very surprised when other things happened:. The scientists were very surprised when other things happened:. Rutherford considered these observations and he concluded:. Rutherford had discovered the nuclear atom, a small, positively-charged nucleus surrounded by empty space and then a layer of electrons to form the outside of the atom. The approach of the positively charged glass rod to P attracts electrons towards P, thus increasing the excess positive charge on G and the bottom end of R.

G therefore moves away from R. If on the other hand you were to approach P with a negatively charged plastic rod, electrons would be repelled from P down towards the bottom of the rod, thus reducing the excess positive charge there. G therefore approaches R. Now try another experiment. Start with the electroscope uncharged, with the gold leaf hanging limply down.