The Big Bang Theory · Season 4
24 episodes listed, beginning 2010-09-23.
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- Episode 1
The Robotic Manipulation
30 minutes
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Penny finds herself along for the ride on Sheldon's first date ever; while Wolowitz finds a new use for a robotic arm.
- Episode 2
The Cruciferous Vegetable Amplification
30 minutes
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Sheldon realizes he won't live long enough to download his consciousness into a robot body, and attempts to extend his lifespan.
- Episode 3
The Zazzy Substitution
30 minutes
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The guys are concerned as Sheldon searches for an alternative to human companionship.
- Episode 4
The Hot Troll Deviation
30 minutes
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An embarrassing secret of Wolowitz's comes to light, while Sheldon and Raj have a small war at work.
- Episode 5
The Desperation Emanation
30 minutes
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Leonard realizes he's the only one without a girlfriend, while Sheldon wants to get rid of his.
- Episode 6
The Irish Pub Formulation
30 minutes
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Leonard keeps an affair secret from Sheldon, Howard and Raj.
- Episode 7
The Apology Insufficiency
30 minutes
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Sheldon's answers during an FBI interview put Wolowitz's security clearance in jeopardy.
- Episode 8
The 21-Second Excitation
30 minutes
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While the guys camp in line for a screening, Penny and Bernadette invite Amy to her first slumber party.
- Episode 9
The Boyfriend Complexity
30 minutes
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Penny asks Leonard to lie to her father, while Howard, Raj and Bernadette pull an all-nighter at a telescope.
- Episode 10
The Alien Parasite Hypothesis
30 minutes
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Amy finds she has sexual feelings for Penny's ex, while Koothrappali and Wolowitz try to prove who would be the better superhero.
- Episode 11
The Justice League Recombination
30 minutes
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The guys find a "super" use for Penny's new boyfriend, Zack, when they enter a costume contest as the Justice League.
- Episode 12
The Bus Pants Utilization
30 minutes
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Leonard's idea for a smartphone app derails his friendship with Sheldon.
- Episode 13
The Love Car Displacement
30 minutes
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Tension runs high when everyone is staying at the same hotel for a science event and Bernadette runs into her ex-boyfriend.
- Episode 14
The Thespian Catalyst
30 minutes
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Sheldon hopes acting lessons from Penny will help him become a better teacher. Meanwhile, Koothrappali fantasizes about his best friend's girlfriend.
- Episode 15
The Benefactor Factor
30 minutes
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A wealthy donor to the university makes Leonard consider how far he's willing to go for the sake of science.
- Episode 16
The Cohabitation Formulation
30 minutes
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As Wolowitz contemplates taking things with Bernadette to the next level, Leonard rekindles his relationship with Raj's sister.
- Episode 17
The Toast Derivation
30 minutes
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Sheldon struggles to cope when he realizes it's actually Leonard who is the center of their social group.
- Episode 18
The Prestidigitation Approximation
30 minutes
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Leonard must choose between new girlfriend Priya and his friendship with Penny. Meanwhile, Howard drives Sheldon crazy with a magic trick.
- Episode 19
The Zarnecki Incursion
30 minutes
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When someone hacks Sheldon's online game account, the guys go on a quest to find the culprit.
- Episode 20
The Herb Garden Germination
30 minutes
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Sheldon and Amy experiment on their friends by spreading gossip, while Howard takes a big step in his relationship with Bernadette.
- Episode 21
The Agreement Dissection
30 minutes
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When Priya uses her lawyer skills to pick apart the roommate agreement, the girls take Sheldon dancing.
- Episode 22
The Wildebeest Implementation
30 minutes
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Raj attempts to cure his social anxiety disorder while Penny uses Bernadette to spy on Leonard and his girlfriend.
- Episode 23
The Engagement Reaction
30 minutes
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When Howard finally breaks the news to his mom that he's engaged to Bernadette, it lands her in the hospital.
- Episode 24
The Roommate Transmogrification
30 minutes
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When Bernadette receives her Ph.D., the guys take joy in reminding an emasculated Wolowitz that he is the only one in their group who isn't a doctor. Meanwhile, Koothrappali becomes Sheldon's new roommate after hearing Leonard and Priya engaging in a "Star Trek" bedroom fantasy.
Original air-order information: TVmaze, CC BY-SA 4.0. Listed through September 10, 2026. Regular episodes only; specials and future air dates are not included.