Based on the article “Will the real atomic model please stand up?,” why did J.J. Thomson experiment with cathode ray tubes?

Question

to specifically identify the nucleus as a separate part of an atom
to determine that electric beams in cathode ray tubes were actually made of particles
to prove John Dalton and Democritus wrong
to determine the exact energy output of cathode ray tubes

Answer 1

J.J. Thomson experimented with cathode ray tubes to determine that electric beams in cathode ray tubes were actually made of particles. His experiments led to the discovery of the electron, demonstrating that cathode rays were composed of negatively charged particles, which challenged the existing atomic models at the time.