How did ernest Rutherford discover his model?

Answer 1

At the time, there was a model known as the Plum Pudding model theorized by J.J. Thompson. Rutherford wanted to test the validity of this model through the Gold Foil Experiment he performed.

In the plum pudding model, an atom was a mass of positive charge with freefloating electrons inside. Rutherford decided to set up a thin sheet of gold foil upright and through his device, launched alpha particles(positively charged Helium ions) into the gold foil. If an atom truly did have a mass of positive charge with freefloating electrons inside, the the alpha particles should have all just gone straight through the foil to the other side, with minor bending in direction.

However, while most did do so, many of the alpha particles bounced into several different, wide and dramatic angles-some even bounced straight back. This led to the theory that there must be a concentrated source of positive charge within the atom causing such rebellious deflection upon contact with the alpha particles, rather than the entire atom being a mass of positive charge.