Scattering Experiment

3. Alpha Scattering

Rutherford measured the specific charge of the alpha particles by deflecting them in electric and magnetic fields, the same method that J.J. Thomson had used to discover the electron.

Rutherford had found the deflection of the alpha particles by measuring their position on a photographic film. While making the measurements, he observed an unusual effect; if the alpha particles passed through a thin sheet of mica, the images on the film were blurred.

The images were sharp if the mica was not present. Something about the mica sheet was causing the alpha particles to scatter at seemingly random small angles, resulting in the blurred images.

Next Page