So I just read that when alpha particle hit the gold foil sparks were created. And these flashes were used to determine the angle of scattering. So were the sparks created because the alpha particles (positive) excited the electrons in the gold foil? And is a spark just that? Light emitted due to Excitation of electrons and them coming back to a lower energy ( de-excitation)?
Also were any electron even excited out of the gold foil?
Best Answer
So I just read that when alpha particle hit the gold foil sparks were created. And these flashes were used to determine the angle of scattering
I think you need to read the text again.
A schematic of the apparatus is as follows.
The alpha particles after they emerged from the gold foil produced flashes of light (you have called the sparks) on a fluorescent screen which were observed using a microscope focussed on the screen.
The flashes of light were produced by the interaction of the alpha particles and the zinc sulphide which coated the screen. The number of alphas hitting the screen per unit time was measured as a function of $\theta$, the angle trough which the alpha particles had been deflected.