The plum pudding model is a historical scientific theory proposed by J.J. Thomson in 1904 to describe the structure of an atom. According to this model, atoms are composed of a positively charged "pudding" with negatively charged electrons embedded within it, resembling plums in a pudding. This model was an early attempt to explain the distribution of charge within an atom. However, the plum pudding model was later challenged by the results of the Rutherford gold foil experiment in 1911, which led to the development of the nuclear model of the atom. This new model proposed that atoms have a small, dense nucleus at their center, surrounded by electrons, fundamentally changing our understanding of atomic structure.