Yesterday I visited a high school in Treviso, a small centre in north-west Italy. The students of the last two years participate in a program called "masterclasses" which includes lessons on particle physics and astrophysics and a visit to the department of Physics in Padova, where they will be taught how to distinguish particle decays using real LHC data.
My lesson was a short story of particle physics, starting from Thomson and Rutherford and ending with the Higgs boson discovery and what may exist beyond. The about 100 students seemed to follow my lesson with interest, although it was quite tough for them, I am sure. In fact I did not spare them some gory details of how, e.g., the hypothesis of strangeness led to the quark model, or how electroweak unification comes about.
The slides of my lesson are available at this link (in Italian only -sorry) in powerpoint format.
Particle Physics For High School Students