(February 22, 2010) Professor Leonard Susskind discusses spontaneous symmetry breaking and gauge invariance. This course is a continuation of the Fall quarter on particle physics. The material will focus on the Standard Model of particle physics, especially quantum chromodynamics (the theory of quarks) and the electroweak theory based on the existence of the Higgs boson. We will also explore the inadequacies of the Standard Model and why theorists are led to go beyond it. This course was originally presented in Stanford's Continuing Studies program. Stanford University www.stanford.edu/ Continuing Studies at Stanford continuingstudies.stanford.edu Stanford University Channel on YouTube: www.youtube.com/stanford