In the The Big Bang Theory episode (Season 4, Episode 20), the plot centers on a social experiment conducted by Sheldon and Amy to test the speed and "virulence" of gossip within their friend group. Plot Summary
: The episode concludes with Amy starting an even more extreme rumor—telling Penny she is pregnant with Sheldon's baby—to see how quickly Leonard finds out. Original Air Date April 7, 2011 Director Mark Cendrowski Major Milestone Howard and Bernadette get engaged [S4E20] The Herb Garden Germination
: The engagement is particularly devastating for Raj, who had been harboring a secret crush on Bernadette and was hoping the breakup rumor was true. Key Episode Details In the The Big Bang Theory episode (Season
: Renowned physicist Brian Greene appears as himself, giving a book reading that Sheldon and Amy attend specifically to heckle. Key Episode Details : Renowned physicist Brian Greene
You can find more details or watch the episode on platforms like IMDb or Apple TV . The Herb Garden Germination | The Big Bang Theory Wiki
: Refers to the mundane "control" rumor Sheldon and Amy used for their social experiment.