Having actually done some of these experiments I comment. Podcast I had read this below earlier in the day and podcasted while walking at night From the syllabus: Structure of the Atom Inquiry question: How is it known that atoms are made up of protons, neutrons and electrons? Students: ● investigate, assess and model the experimental evidence supporting the existence and properties of the electron, including:  – early experiments examining the nature of cathode rays – Thomson’s charge-to-mass experiment  – Millikan's oil drop experiment (ACSPH026)  ● investigate, assess and model the experimental evidence supporting the nuclear model of the atom, including:  – the Geiger-Marsden experiment  – Rutherford’s atomic model – Chadwick’s discovery of the neutron (ACSPH026)