| On consideration, I realized that this scattering backward must be the result of a single collision, and when I made calculations I saw that it was impossible to get anything of that order of magnitude unless you took a system in which the greater part of the mass of the atom was concentrated in a minute nucleus | |
|---|---|
| However, the actual results surprised Rutherford | It was almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you |
series of experiments 1908-1913 by Hans Geiger and Ernest Marsden, directed by Ernest Rutherfofrd, at the University of Manchester, proving the existence fo the atomic nucleus through alpha particle scattering on gold foil.
4| Rutherford's experiment consisted of a beam of , generated by the of , was directed normally onto a sheet of very thin foil in an evacuated chamber | Although many of the alpha particles did pass through as expected, many others were deflected at small angles while others were reflected back to the alpha source |
|---|---|
| A screen at the focus of a microscope was used as a detector; the screen and microscope could be swivelled around the foil to observe particles deflected at any given angle | They observed that a very small percentage of particles were deflected through angles much larger than 90 degrees |
Note that the image is not to scale; in reality the nucleus is vastly smaller than the electron shell.
.
22