Geiger-Marsden experiment

The Geiger-Marsden experiment, also known as the gold foil experiment, involved firing alpha particles (tiny, positively charged particles) at a thin sheet of gold foil. Most particles passed through with little deflection, but some were deflected at large angles, and a few even bounced back. This revealed that the atom has a small, dense, positively charged nucleus at its center, surrounded by mostly empty space. This experiment was crucial in developing the modern atomic model, showing atoms are not solid balls but have nuclei that contain most of their mass and charge.