The Big Bang Theory Wiki

Season 3 of The Big Bang Theory returned to television on September 21, 2009, and contained 23 episodes. It was originally aired on CBS from September 21, 2009, to May 24, 2010, over 23 episodes. It has received higher ratings than the previous two seasons with over 15 million viewers. The main focus of the season was the romance between Leonard and Penny which was hinted at the end of Season 2.


Main Cast

Recurring Cast

Guest Cast


Episode (Series) Episode (Season/Ep#) Title Original Air Date Directed By Description
41 301 The Electric Can Opener Fluctuation September 21, 2009 Mark Cendrowski Following his return from the Arctic, Sheldon is very excited over the prospects that his research in the Arctic has yielded until he learns that the guys fudged his data. Penny is happier than most now that Leonard is back.
42 302 The Jiminy Conjecture September 28, 2009 Mark Cendrowski The guys discover Leonard is not as happy with the sex, while Sheldon, Howard and Raj are on a quest over a bet involving a cricket.
43 303 The Gothowitz Deviation October 5, 2009 Mark Cendrowski After an accident causing Penny's bed to break, Sheldon must deal with Penny staying in his apartment. Raj and Howard and going to a Goth bar to meet girls.
44 304 The Pirate Solution October 12, 2009 Mark Cendrowski Raj must find a new job or be sent back to India. Sheldon has a solution, which is to allow Raj to work "for" him, rather than work "with" him. Raj reluctantly accepts the offer. Howard is lonely and tries hanging out with Leonard and Penny.
45 305 The Creepy Candy Coating Corollary October 19, 2009 Mark Cendrowski Sheldon enters a trading-card competition upon learning that Wil Wheaton, who he hates for not coming to a sci-fi convention he went to, will also be attending. Howard gets Leonard to have Penny set him up with a blind date, a girl named Bernadette.
46 306 The Cornhusker Vortex November 2, 2009 Mark Cendrowski Sheldon, who grew up in Texas where football was popular, teaches Leonard how to understand it so that he can try to fit in with Penny's friends. Howard and Raj have a dispute during their kite fighting game.
47 307 The Guitarist Amplification November 9, 2009 Mark Cendrowski An argument between Leonard and Penny causes Sheldon to freak out with the couple treating him like they are his surrogate parents.
48 308 The Adhesive Duck Deficiency November 16, 2009 Mark Cendrowski Leonard is with Raj and Howard on a camping trip to watch the Leonid Meteor Shower, but all three succumb to 'magic' cookies they get from Deadhead campers nearby. Sheldon comes to Penny's rescue after she dislocates her shoulder and Sheldon has to drive her to the hospital.
49 309 The Vengeance Formulation November 23, 2009 Mark Cendrowski Wolowitz's new girlfriend, Bernadette, asks him where their relationship is going after their third date. He avoids her for a week and gets some relationship advice from his own fantasy characters. Sheldon plans revenge against his arch-nemesis Barry Kripke.
50 310 The Gorilla Experiment December 7, 2009 Mark Cendrowski Bernadette shows an interest in physics and gets invited to watch Leonard's experiment which makes Wolowitz jealous. Penny then asks Sheldon to teach her a little physics so she can understand Leonard's work.
51 311 The Maternal Congruence December 14, 2009 Mark Cendrowski A visit from Leonard's mother, Dr. Beverly Hofstadter, delights Sheldon and horrifies Leonard. Penny is upset because Leonard didn't mention his mother's visit to her.
52 312 The Psychic Vortex January 11, 2010 Mark Cendrowski Sheldon and Koothrappali attend a university mixer and get dates with Abby (Danica McKellar) and her friend Martha (Jen Drohan). Leonard and Penny get into a fight over her belief in psychics.
53 313 The Bozeman Reaction January 18, 2010 Mark Cendrowski When their apartment is robbed and their TV, video games, and computers are stolen, Leonard and Sheldon turn to Howard to create a state-of-the-art security system. Sheldon gets caught in the security net and decides he needs to leave Pasadena.
54 314 The Einstein Approximation February 1, 2010 Mark Cendrowski Sheldon's search for the answer to a physics problem keeps him up all night for several days making him both obsessed with finding the answer and crazier than usual. He end up in a mall ballpit shouting "Bazinga!" at Leonard and working with Penny at the Cheesecake Factory.
55 315 The Large Hadron Collision February 8, 2010 Mark Cendrowski Leonard announces he is taking Penny to see CERN's Large Hadron Collider in Switzerland, Sheldon  reminds him that their Roommate Agreement dictates that he should take him.
56 316 The Excelsior Acquisition March 1, 2010 Peter Chakos Sheldon misses his chance to meet comic book legend Stan Lee when he has to attend traffic court after receiving a ticket because of Penny.
57 317 The Precious Fragmentation March 8, 2010 Mark Cendrowski On the way to buy Chinese food, the guys see someone that looks like Adam West and follow him to a garage sale, where they buy a box of merchandise for 60 dollars. They ignore Penny's anger at not getting food, and among other things they find a 'Lord of the Rings' ring which tests the gang's friendship.
58 318 The Pants Alternative March 22, 2010 Mark Cendrowski Sheldon's friends come to his aid when his fear of public speaking stands between him and a coveted award.  Penny helps him calm his nerves with wine and ends up addressing the audience drunk.
59 319 The Wheaton Recurrence April 12, 2010 Mark Cendrowski

One night after making love, Leonard surprises Penny by saying "I Love You," but she can only say to him is "Thank You". The situation gets worse when they end up between Sheldon and Wil Wheaton during a bowling tournament.

60 320 The Spaghetti Catalyst May 3, 2010 Anthony Rich Leonard and Penny have broken up. Sheldon meets Penny decide to have dinner together and Sheldon must deal with being friends with Leonard's ex-girlfriend. 
61 321 The Plimpton Stimulation May 10, 2010 Mark Cendrowski Dr. Elizabeth Plimpton comes to Caltech as Sheldon's guest and has quite a sexual appetite which makes Penny quite jealous. 
62 322 The Staircase Implementation May 17, 2010 Mark Cendrowski Leonard tells Penny the story of how he first met Sheldon, meeting Howard and Raj, Leonard's affair with Joyce Kim and how the elevator got broken. 
63 323 The Lunar Excitation May 24, 2010 Peter Chakos The guys set up an experiment on the building's roof to bounce a laser off the moon and invite Penny and her date to join them. Penny learns that she can no longer tolerate dumb men and ends up sleeping with Leonard. Raj and Howard find a match for Sheldon, Amy Farrah Fowler.