Final answer:
The gold foil experiment involved bombarding thin sheets of gold foil with alpha particles. It revealed the existence of a small, dense, positively-charged nucleus in the atom, challenging the existing model of the atom. The experiment had a significant impact on our understanding of atomic structure.
Step-by-step explanation:
The gold foil experiment, conducted by Ernest Rutherford in 1911, involved bombarding very thin sheets of gold foil with fast-moving alpha particles. Alpha particles are positively charged particles with a mass about four times that of a hydrogen atom. Rutherford and his team expected the alpha particles to pass straight through the gold foil with little to no deflection, similar to bullets fired through a Styrofoam sheet.
However, they observed that while most of the alpha particles did pass through the foil un-deflected, a small percentage of particles were deflected at larger angles. This led Rutherford to propose the idea of a small, dense, positively-charged nucleus at the center of the atom, which would explain the deflections.
The experimental setup for the gold foil experiment involved using a radioactive source that emitted alpha particles, directing them towards a thin sheet of gold foil, and surrounding the foil with a screen to detect the deflected particles. This experiment challenged the existing plum pudding model of the atom and paved the way for the development of our current understanding of atomic structure.