For Rutherford's alpha scattering experiment where he fired alpha particles at a thin sheet of metal to determine the size of the nucleus, please can someone give me the direct link between his observations and his conclusions e.g. this observation lead to this conclusions.
This is a link with the conclusions from the experiment and which observations lead to which conclusions.
When Rutherford mathematically investigated the results he proposed a model that explained the results that Geiger and Marsden obtained.
The fact that the vast majority of the alpha particles got straight through led Rutherford to propose that the atom was composed primarily of empty space.
The fact that backscattering occurred in 1 in 8000 alpha particles indicated that the nucleus was:
small (that was why so few were affected)
massive (meaning containing lots of mass - he knew the electrons had very little mass and the fact that all of the positive charges were concentrated into a small area meant that the mass was concentrated there too)
positively charged (because it repelled the alpha particles) nucleus in the centre of the atom (neutrons had not been discovered at that time - so he made no mention of them!).
All these are from the website linked.