What is the plum pudding model?

The plum pudding model, also known as the Thomson model, was a scientific theory proposed by the physicist J.J. Thomson in 1904 to explain the structure of the atom. At that time, it was widely believed that atoms were indivisible, but Thomson's experiments with cathode rays suggested otherwise. Thomson's model proposed that the atom was made up of a uniform positive charge throughout, with negatively charged electrons embedded within it, like raisins in a plum pudding. This was a significant departure from the earlier "billiard ball" model of the atom proposed by John Dalton, which suggested that atoms were solid, indivisible spheres. Thomson's plum pudding model was later replaced by the Rutherford model, which proposed that atoms had a central nucleus, containing most of the atom's mass, with electrons orbiting around it. However, the plum pudding model played an important role in the development of atomic theory and was a significant step toward our current understanding of the structure of the atom.