Which experiment involved alpha particles as a key part of its investigation?

The experiment that involved alpha particles as a key part of its investigation is the Gold Foil Experiment. Conducted by Ernest Rutherford in 1909, this groundbreaking experiment sought to probe the structure of the atom. In this experiment, a source of alpha particles was directed at a thin foil of gold.

The interaction of the alpha particles with the gold atoms provided critical insights into atomic structure. Most of the alpha particles passed through the foil with little deflection, which suggested that atoms are mostly empty space. However, a small fraction of the particles were deflected at large angles, indicating the presence of a dense, positively charged core within the atom, which Rutherford later identified as the nucleus.

This experiment was pivotal in refuting the plum pudding model of the atom and led to the development of the nuclear model of the atom, fundamentally reshaping the understanding of atomic structure. The role of alpha particles was crucial, as their behavior when encountering the gold foil was instrumental in drawing conclusions about the arrangement and composition of atoms.