Episode Titles: Diffusion

 You are viewing a list of 1 The Big Bang Theory episode featuring "Diffusion" in their title.

  • The Ornithophobia Diffusion

    Season 5, Episode 9 - The Ornithophobia Diffusion
    Aired November 10, 2011

    Leonard and Penny spend time alone together as friends for the first time. Meanwhile, Sheldon is forced to overcome his fear of birds after one nests outside his apartment window.