How did Rutherford discredit Thomson's plum pudding model of an atom?

He didn't discredit the plum pudding model of the atom, she proved it.

He conducted an experiment using gold foil and alpha particles.

He conducted experiments with a cathode-ray tube.

He conducted an oil drop experiment.

He conducted an experiment using gold foil and alpha particles.

Explanation:

In his experiment he use the alpha particles (which are positive) emitted by a radioactive element. If Thomson's plum pudding model was correct, the beam would go straight through the gold foil. But the alpha particles were deflected in all directions, some right back at the source. This suggest that the atom's positive charge was concentrated in a much tinier volume than Thomson imagined

He conducted an experiment using gold foil and alpha particles.

Explanation:

Ernest Rutherford in 1911 performed the gold foil experiment which provided a better outlook to the structure of the atom. In his experiment, he bombarded a thin gold foil with alpha particles. Most of the alpha particles passed through the gold foil and just a few was deflected back.

This observation led Rutherford to propose the nuclear model of the atom in which an atom has a small positively charged centre and electrons moving round it.