The Big Bang Theory Season 2 Episode 13 - The Friendship Algorithm


Introduction of The Big Bang Theory


Leonard and Sheldon are brilliant physicists, the kind of "beautiful minds" that understand how the universe works. But none of that genius helps them interact with people, especially women. All this begins to change when a free-spirited beauty named Penny moves in next door. Sheldon, Leonard's roommate, is quite content spending his nights playing Klingon Boggle with their socially dysfunctional friends, fellow Caltech scientists Wolowitz and Koothrappali. However, Leonard sees in Penny a whole new universe of possibilities... including love.

Main characters in the episode:

Sheldon Cooper(Jim Parsons)
Sheldon is the uber geek, he possesses a Master's degree and 2 PhDs, and conducts string theory research at Caltech. He shares an apartment with Leonard.Sheldon started college at the age of 11, receiving his first PhD at 16.

More information about Sheldon Cooper


Leonard Hofstadter (Johnny Galecki)

Leonard is an experimental physicist at Caltech. He shares an apartment with Sheldon Cooper.While Leonard, along with the other geeks, is somewhat socially inept, Leonard would like to be better accepted outside of his geeky social group.

More information about Leonard Hofstadter

Howard Wolowitz(Simon Helberg)

Howard Wolowitz is a 27 year old engineer. He is the only one who doesn't have a PhD. Howard is a multi-lingual speaker whose many tongues he uses to impress the ladies, sadly to little avail.

More inormation about Howard Wolowitz

Rajesh Koothrappali(Kunal Nayyar)

Rajesh Koothrappali is an Astrophysicist from India. He now lives in California. His social anxiety is suppressed only by alcohol. He rarely talks to women when not intoxicated.
More information about Rajesh Koothrappali

Barry Kripke(John Ross Bowie)
Another scientist at Caltech, a co-worker of Leonard and Sheldon. He speaks with a lisp.He has been described by Howard as a "jerk" and a "ginormous knob" by Rajesh. Sheldon notes (to his face) that he is "generally considered unlikeable".

Search for more characters on IMDB:

Synopsis of today's episode:


Socially awkward Sheldon develops a scientific procedure for making friends. He needs to use an open science grid computer that is in Barry Kripke's office, but Leonard tells Sheldon that only Barry's friends can use it ... ergo, Sheldon decides he must become friends with him. After repeated rebuffs from Kripke, Sheldon finds a children's book in the bookstore (where he is hurried out by Leonard who finds him innocently chatting to a little girl in view of a security camera) about how to make friends. He designs a flowchart for accomplishing this task. He goes rock climbing with Kripke but faints halfway up when he sees how far he has come. Sheldon invites him over to his apartment, much to the disgust of everyone else. Raj is informed he is being replaced by Kripke as five friends would be too many to handle. Barry then tells Sheldon there is a sign-up sheet for the computer and Barry has no control over it. Sheldon then dismisses Barry as his friend and goes back to his other four friends: Leonard, Howard, Raj, and Penny.

Watch the whole video HERE:

Listening activities

Today we will watch part of the episode and will have several questions.

Part 1: Sheldon went to the bookstore and met a little girl.
See the video here:

Part 2: Sheldon made a "friendship algorithm" and tried to make friend with Kripke by using it.
See the video here:

Part 2 Listening activity
  1. Which book helps Sheldon come up with the friendship algorithm?

  2. What are the three activities that Kripke proposed when Sheldon tried to find a “common interest”?

  3. Who solved the infinite loop? How?

  4. What activity does Sheldon agree to as a compromise?

Part 3: Sheldon and Kripke went rock climbing.
See the video here:
See the links below for videos that explain the monolith reference.

Part 3 Listening activity

1. How did Sheldon mock the staff at the rock climbing venue?
2. What kind of swimming does Sheldon think he is doing when climbing the wall?
3. How does Sheldon end his first rock climbing experience?


condolences-an expression of a sympathy that you feel for somebody when a person in their family or that they know well has died.
void- a large empty space.
moth-a flying insect with a long thin body and four large wings, like a butterfly, but less brightly colored, fly mainly at night and are attracted to bright lights.
moth ball- a small white ball made of a chemical with a strong smell, used for keeping moths away clothes.
pretzel- a crisp salty biscuit in the shape of a knot or stick, often served with drinks at a party.
extrapolate- to estimate something or form an opinion about something, using the facts having now and that are valid for one situation and supposing that they will be valid for the new one.
anthropomorphize- treat gods, animals or objects as if they had human qualities.
algorithm- a process or set of rules to be followed in calculations or other problem-solving operations, especially by a computer.
booth- a small temporary tent or structure at a market, fair, or exhibition, used for selling goods, providing information, or staging shows.
distilled- extract the essential meaning or most important aspects.
flowchart-a graphic that shows the connections between the different stages of process or parts of a system.
crate- slatted wooden case used for transporting goods.
beverage- any type of drinks except water.
recreational- activity done for enjoyment when one is not working.
loop-a set of instructions that is repeated again and again until a particular condition is satisfied.
ventriloquism- the art of speaking without moving lips and of making it look as if your voice is coming from another person.
loop counter- change with each part of a loop, providing a unique value for each individual part. The loop counter is used to decide when the loop should terminate and for program flow to continue to the next instruction after the loop.
objectionable-unpleasant, offensive.
dummy- a model or replica of a human being.
monolithic- formed of a single large block of stone, very large and characterless.
Hominids-human, or creatures that lived in the past which humans developed from.
prudent- sensible and careful when you make judgments or decisions; avoiding unnecessary risks.
evolutionary- connected with gradual development and change.
altitude- the height above sea level.
cement- to make a relationship, an agreement stronger.

harness- a set of strips of leather for fastening something to a person’s body or to keep them from moving off or falling.
incontinence- the lack of ability to control the bladder and bowels.
tangent- a straight line or plane that touches a curve or curved surface at a point , but if extended does not cross it at that point.

asymptote- a straight line that continually approaches a given curve but does not meet it at any finite distance.


cope with- deal with, handle some situation
hit it off (with somebody)-have good friendly relationship with somebody.
Hear sb. out- to listen until someone finished saying what they want to say.
pass out- faint, becoming unconscious.


Whole episode is here:

Clips from the movie 2001: A Space Odyssey:
Just watch the first 4 minutes of this clip:
Watch the first 5:25 seconds of this clip:

About 2001: A Space Odyssey:

2001: A Space Odyssey is a 1968 epic science fiction film produced and directed by Stanley Kubrick, and co-written by Kubrick and Arthur C. Clarke. The film deals with thematic elements of human evolution, technology, artificial intelligent, and extraterrestrial life. It is notable for its scientific realism, pioneering special effects, ambiguous imagery that is open-ended to a point approaching surrealism, sound in place of traditional narrative techniques, and minimal use of dialogue.

Check it out on wiki:

Cultural refrences



Cockatoo is one kind of Parrot which can be found in Australia, Papua New Guinea, Indonesia & south Philippine. The name cockatoo originated from the Malay name for these birds, kaka(k)tua ( means “old brother or old sister”)

Curious George
CURIOUS GEORGE is an animated series based on the popular books by Margret and H.A. Rey and airs daily on PBS KIDS.



It is traditionally a four-day event (Thursday through Sunday — though a three-hour preview night on Wednesday is open to professionals, exhibitors, and some guests pre-registered for all four days) held during the summer in San Diego, California, United States, at the San Diego Convention Center.

Some geeky T-shirts:



The Friendship Algorithm


1. Do you have any classmate or friend who can’t make friend easily? What kind of characteristic does he/she have that results in this kind of difficulty?
2. Which common interest do you usually share with your new friends?
3. What is the most embarrassing/unforgettable experience you have had when you were hanging out with your friends?