PX156 - D6 - rutherford scattering experiment

$1910-11:$ $\alpha$ particles were known to be heavy, stable, positively-charged, with speed $\sim {10}^{7}m{s}^{-1}$; travel a few centimetres in air, $\sim 0.1mm$ in solids

a beam of $\alpha$ particles bombarded on a thin gold-foil target

surrounded by zinc sulphide scintillation screens to detect the scattered particles, which produces a flash of light when it hits the scintillation screen

most particles passed through, only some were reflected

showed that atoms are mostly empty spaces with the positive nuclei occupying a tiny volume

size of the nuclei $\sim {10}^{-14}m$, total volume $\sim {10}^{-12}$ of the atom, contains $99.95\mathrm{\%}$ of the mass