Nobody can deny Sheldon's obsession with science, but what if that passion is put to the test? "The Big Bang Theory" season 8, episode 6 spoilers reveal that the genius will find a lot about himself through an empty bucket.

Meanwhile, Penny and Leonard's relationship will be tested anew by money, according to "The Big Bang Theory" season 8 spoilers from Hypable.

The next episode is called "The Expedition Approximation" and Sheldon and Raj will test their mettle for science.

The teaser clip shows Raj enumerating the list of challenges of going underground and Sheldon appears to be okay with them.

"However, we learn in here that he also very-quickly has a breaking point, and it comes the moment that it is mentioned that they would have to use a bucket for a toilet," said Cartermatt. "The only other choice is that they wait for 12 hours before using the bathroom, and Sheldon's not okay with that."

"The Big Bang Theory" season 8, episode 6 spoilers can be gleaned from the synopsis released by CBS which reads: "Sheldon and Raj test whether they could survive a dark-matter research expedition in a salt mine by simulating the conditions in a steam tunnel. Meanwhile, Leonard and Penny seek advice from Wolowitz and Bernadette after they fight about money."

Executive produce Steve Molaro told Inquistr that just like any other couple, Penny and Leonard will argue over money.

"She's really focused on this new career. I don't think they're in a rush. They're happy, they're engaged and, like a lot of people, they may be engaged for a while," he said. "But it does raise issues like money, combining money in the future and who has credit card debt and what that all means. Those kind of issues start to come up, which I find more interesting than the actual wedding planning."