Why did Rutherford say that bombarding atoms with particles was like playing with marbles What subatomic particle did Rutherford discover during this phase of his work?

Rutherford compared bombarding atoms with particles to playing with marbles because, just as marbles can bounce off each other or collide in unpredictable ways, particles striking atoms can lead to various outcomes, such as deflections or reactions, revealing the structure of the atom. During this phase of his work, Rutherford discovered the nucleus of the atom and identified the proton as a subatomic particle, fundamentally altering our understanding of atomic structure.