Watch The Big Bang Theory Online - Full Episodes

The Big Bang Theory is a comedy that depicts the private and professional lives of four young men who work in a California University's science department. The comedy is derived from the geeky nature of these young men who often have awkward and embarrassing social interactions with women. Sheldon and Leonard share an apartment, while Raj has his own apartment and Howard lives with his mother. Each of the four characters has his own distinct personality which enhances the interactions of the group as a whole.

Sheldon is the member of the group who is considered to be the brainiest. This opinion is largely held by Sheldon, who sees himself as a superior being to most people on the planet. Sheldon thinks in logical terms which makes it hard for him to understand the decisions people make when they use their emotions. Sheldon holds a doctorate in physics which enables him to work in the physics department of the university. Although he has a superior mentality, he also has moments where the little boy in him comes out. This is especially true when he gets sick and wants to be waited on by either Leonard or their neighbor Penny, who will sing him a child's lullaby called Soft Kitty.

Leonard also has a doctorate in physics, but does not have the superior attitude that Sheldon has. Leonard's personality is often needy and more empathetic than Sheldon's. The odd circumstances of their childhoods placed them in families which were in direct opposition to the personalities they possessed. Leonard comes from a family of doctors with his mother holding a degree in psychiatry. In some episodes she visits Leonard and spends her time analyzing everything he does. Sheldon on the other hand, comes from a classic Texas family where his mother is a devout believer in Jesus. She also comes to visit on occasion and is the only person who seems to have any degree of control over her son.

Howard is a typical Jewish boy living at home with his mother even though he is well into his thirties. Howard is the only member of the group who does not possess a degree in physics. He has a Master's degree in engineering from MIT. This enables him to work in the engineering department at the same university as Sheldon and Leonard. Howard often makes devices which are used by the space program. In one episode he designed a toilet for use on the space station. After the toilet was already in place on the space station he discovered the design had a flaw. Instead of disposing of the waste through the base or bottom of the receptacle, it shot it out through the top.

Raj is also a physicist who specializes in astronomy. Raj comes from India where his parents are extremely wealthy. Raj and Howard have personalities which balance each other out. Howard is often obnoxious and considers himself a playboy or ladies man, while Raj has a more feminine side which makes him very sensitive to the needs of others. He does like to meet women, but has an emotional block which prevents him from being able to speak while in the presence of any woman other than his mother or sister. This block is removed whenever he drinks alcohol.

Penny is a young woman who lives across the hall from Sheldon and Leonard. From the moment she first moved in Leonard was smitten with her. Penny's character is free spirited and beautiful and not even close to having the amount of education of any of the young men in the group. She comes from Nebraska and has a street wise attitude which allows her to stand up and take charge of situations which usually render the men useless. Penny works as a waitress at the Cheesecake Factory and dreams of becoming an actress.

Additional characters who develop in the series include Stuart, who owns a comic book store where the guys often hang out and Bernadette, who works part-time at the Cheesecake Factory with Penny. Bernadette also works in the science department at the university and eventually becomes Howard's girlfriend. Later in the series, Sheldon also meets and forms a relationship with a female scientist named Amy who becomes friends with Penny and Bernadette.