Kathleen

Barry Kripke, Ph.D. is a Caltech-physicist-turned-string-theorist and an unlikable colleague of Leonard and Sheldon. He has a case of, where he pronounces "r" and "l" as "w", much like Elmer Fudd in Looney Tunes. With a knack for ribbing people, he is an on-and-off to Sheldon, Leonard, Howard, and Rajesh.

Season 1
Kripke has no appearances in any episodes of Season 1.

Season 2
In his first appearance, he pitted his "kiwwa wobot," the Kripke Krippler (or as he called it, the "Kwipke Kwippwuh"), originally designed for the  Fighting League Round Robin Invitational, against the guys' robot (M.O.N.T.E.) in an unofficial robot battle at the Caltech kinetics lab ("The Killer Robot Instability"). On another occasion, Barry ridiculed Leonard's unsuccessful decay experiment, while Sheldon attempted to befriend Kripke in order to gain access to an open science grid  to carry out research on structure formation in the early. However, Sheldon's efforts were abandoned when he realized that Kripke had no say in who used the computer. Kripke comes on to Penny the same way Howard does, after disgusting her by cleaning his gum pockets for new food, but deciding the name Penny wasn't hot enough he proceeded to call her 'Woxanne' "Roxanne", much to her annoyance ("The Friendship Algorithm").

Season 3
He continued to appear in Season 3, where he mocked Sheldon consistently. Kripke humiliated Sheldon for his retraction regarding his blunder, and stated that, unlike this situation, Einstein's cited mistake concerning the  might have been right all along ("The Electric Can Opener Fluctuation"). He injected into Sheldon's office while he was doing a  interview, sharing it via portable radio in the cafeteria. With encouragement from Leonard and Raj, Sheldon retaliated by dumping foam all over Kripke and the lab while the president of the university and the board of directors were in the room, as he was showing them how a  grant was being put to use with a micro-controlled plasma experiment ("The Vengeance Formulation").

Season 4
A year later, he was invited to Sheldon and Leonard's apartment by Sheldon during the former's attempt to establish a new social group, along with Zack Johnson, Stuart Bloom, and (Sheldon hopes) LeVar Burton, after Sheldon becomes angry with his friends for eating at Raj's apartment. Zack impresses Barry and Stuart with his tale of a woman in a, and later the three end up singing  using the karaoke machine Barry keeps in his car, much to Sheldon's dismay ("The Toast Derivation").

Season 5
In this season, Barry tells Sheldon, who still has some rivalry with him, as well as Raj, that Professor Rothman urinated in the lab again and his retirement potluck had to be moved up. When Raj speaks to his Siri, Kripke, still in their office, points out that he too has that phone and complains about voice recognition difficulties, supposedly unaware of his own rhotacism or that Siri can't acknowledge it. On the matter of the phone, he further reveals his perverse nature by stating that his phone took photos of his "junk" for Craigslist as Raj is offended by his negativity regarding Siri ("The Beta Test Initiation").

In "The Rothman Disintegration", Barry argues with Sheldon over who will receive Professor Rothman's office, taking the issue to President Siebert, and challenging Sheldon to a basketball match, a game they are equally bad at. He appears again briefly in "The Stag Convergence" as a party guest before Howard's, but he kept on complaining that there were no.

Season 6


Kripke returned in "The Cooper/Kripke Inversion" besting Sheldon at work and causing him to lie about Amy (which Kripke believed to be why Sheldon's paper wasn't as good as expected). Kripke enjoyed hearing about Sheldon's "sex life," prying for details.

During the events of "The Tenure Turbulence," Kripke impresses the committee with ease, especially compared to Leonard, Sheldon, and Raj.

Season 7
After Sheldon retracts his paper on the existence of a new super-heavy element in "The Discovery Dissipation", Kripke came to his office to mock him, suggesting that he should take on a identity as "The Retractor". When Sheldon responded with a comment about his speech impediment, Kripke seemed hurt, but actually used Sheldon's apology as the setup for another "Retractor" joke. In "The Relationship Diremption", Barry taunts Sheldon after new discoveries make his twenty years of work on String Theory useless, and laughs upon hearing about him drunk dialing Stephen Hawking. He also taunts Howard by referring to him as "Cwogziwwa" (Clogzilla).

Season 8
In "The Champagne Reflection", Barry is seen as a guest of Sheldon's broadcast, "Sheldon Cooper presents Fun with Flags". He is playing the game "Flag or Not Flag", where he is shown flash cards and has to identify the flags. He calls out "fwag" or "not a fwag" and appears to be very good at the game.

In "The Comic Book Store Regeneration", Barry thanks Amy for her insight in suggesting how a approach to  may be applicable to string theory. As such, his paper received an amazing response. This irked Sheldon, since his string theory research hit a dead end and Amy did not lend help to him.

Season 9
In "The Perspiration Implementation", Barry Kripke instructs the guys in when they want to join the new fencing club. He learns that Sheldon and Amy are broken up and he asks her out. Amy turns him down, but she does get a naked picture of him that shocks Penny and Bernadette, but does not seem to bother Amy.

In the following episode "The Helium Insufficiency", Kripke has all of the university's liquid helium reserve in his control, which he refuses to let Leonard and Sheldon use for their experiment to test their theory, unless they include his name on their project.

In "The Valentino Submergence", he interrupts Fun with Flags to talk about his love life. He ends up creeping Amy out with questions demanding details about her sex life.

In "The Celebration Experimentation", Kripke attends Sheldon's birthday and keeps hitting on Leonard's mother who enjoys the attention, which annoys Leonard. He also knows that Bernadette is expecting, but no one had told Stuart.

Season 10
He reappears in "The Geology Elevation", where he is the only person besides Howard who likes the motorized Stephen Hawking toy. However, Howard realizes how offensive the toy really is when Kripke wants to drive it into the women's restroom.

He is mentioned in "The Allowance Evaporation" when Sheldon lists the people he told about him and Amy sleeping together once a year.

Season 11
He reappeared in "The Tesla Recoil". After learning Sheldon went behind their backs to work with the military again, Leonard and Howard say Sheldon is like Thomas Edison, taking credit for other's ideas, while they are more like Nikola Tesla. Leonard and Howard bring in Kripke to help create a better idea than Sheldon's, but Kripke betrays them and goes to the military himself, cutting all three of them out.

He reappeared appear in "The Athenaeum Allocation". Shamy are trying to book their wedding at the Athenaeum at Caltech, but Kripke has already selected that location as the place where he's going to have his birthday party. Eventually, after scrubbing some irradiated grease out of barrels, Shamy are allowed to have the Athenaeum as their wedding location, but Amy doesn't like how Kripke is going to sing "Volare" at their wedding, and they are thinking about other locations like the planetarium.

Personality
Despite being a stereotypical, Barry apparently tries to be fairly sporty, as shown in "The Friendship Algorithm". In that episode, it was implied that he enjoys, water polo,and. "The Rothman Disintegration" reveals that Kripke and Sheldon are "equally bad" at sports. Unlike his colleague, Kripke is fully aware of his limitations and shortcomings, even admitting that he is "creepy, pathetic and can't get girls". He has been known to make inappropriate comments to women, photograph his own and upload the shots to the Internet ("The Beta Test Initiation"), and enjoys hanging out at a  near his, which has a free  ("The Rothman Disintegration"). He also seems to enjoy strippers.

Kripke is often suggested to be coasting in his job -- in one instance he even goes as far to say that "[he] says [he]'ll prove something that can't be proved [string theory], then use the money for 'wiquow and bwoads' and broads]". In other instances he engages in robot fighting and makes numerous allusions to his (though he appears mostly romantically unsuccessful). On the other hand, in "The Cooper/Kripke Inversion", Sheldon admits Kripke's grant proposal for a for the university is "leaps and bounds" ahead of his [Sheldon's] own. This suggests that Kripke is quite capable -- despite Leonard not believing Kripke to be smarter than Sheldon, Kripke is apparently able to work at Sheldon's level. This may be the reason for Kripke's success in retaining his job despite his apparent predilection for coasting.

Trivia

 * Like Stuart, Kripke appears in all seasons except Season 1.
 * One of Kripke's wesearch concentwations is the physics of fusion plasmas, illustrated by his work on a grant proposal for a new fusion reactor. He has also referred to himself as a "stwing pwagmatist", or string pragmatist. As he is a, he most likely studies the between string theory and the . (Analogous parameters to those of "classical" plasma physics can be used to characterize the QGP in liquid state.)
 * He has many interests, including Star Trek (although he admits he hasn't watched it since he discovered the strip club near his apartment),, karaoke, , polo, water polo and rock climbing, but he doesn't like monkeys.
 * Sheldon has seniority over him, having arrived at the university before Kripke.
 * Barry's Siri recognizes him as "Bawwy" as it stated when he asked it to "wecommend a westauwant" (recommend a ; however, beyond calling him his name as he fed it into the program, Siri is unable to parse Barry's rhotacism, resulting in Barry being highly dissatisfied with the software (in this case he is implied to be unaware of the distortion in his speech produced by his impediment).
 * Barry is ostensibly named after and.
 * It's also possible that the name "Kripke" is a play on the name of the software protection program "Crypkey." It could also be a play on words for "Crypt Key" a popular item within games.
 * Another possible origin could be the name of the 'makeout-place' that is mentioned in "", 'Mike Kripke's Basement'.
 * Through all his appearances on the series, Sheldon won only once against Kripke, in the episode "The Rothman Disintegration", where Sheldon managed to snag the former office of Professor Rothman (who had taken leave of his faculties, likely permanently) in which Kripke was also interested, by defeating Kripke in an impromptu ball bounce height contest held in the university gym (originally a basketball game, which was later changed due to both of them being lousy at the sport).
 * In the version of the show, Barry does not have rhotacism in the first three seasons, but he speaks with a German accent in season 4. It is not until the fifth season that his rhotacism appears.
 * Also, in the version of the show, instead of rhotacism, he pronounces "s" and "c" as "th", and "r" as "g" (e.g., he pronounces the Portuguese word "restaurante" as "gethtaugante")
 * When asked on Twitter if Kripke was aware of his rhotacism, actor John Ross Bowie suggested he was not, though the episode "The Discovery Dissipation" later made it clear that he is; however, the issue is portrayed inconsistently: in "The Beta Test Initiation", Barry cannot fathom why his Siri personal assistant app cannot parse his rhotacistic speech; however, in "The Discovery Dissipation" he reacts to Sheldon's off-color taunt about his impediment in a way which clearly shows he is aware of it.
 * In "The Toast Derivation" Sheldon unintentionally called him "Bawwy" when introducing him to Zack and Stuart.
 * In Season 10, since he only appeared in one episode ("The Geology Elevation"), he did not antagonize Sheldon because he only had a minor appearance in one scene. Season 10 is the only season to only feature Barry once in a season, where as in previous seasons, he reappeared in various episodes. This is due to Bowie filming Speechless.
 * His birthday might be May 12th due to Kripke having booked the Athenaeum for his birthday party.