The Expedition Approximation
'The Expedition Approximation' - Season 8, Episode 6
Sheldon and Raj consider applying for a dark matter research expedition in a salt mine, but first they test their ability to survive the rough conditions by emulating the conditions in the university's steam tunnel. Meanwhile, Leonard and Penny have an argument about money and seek help from Howard and Bernadette.
Air Date: October 20, 2014.