As a subtrope of {{Infodump}}, an easy way to present {{Exposition}} in a story is to have a character, often a lead character, as a lecturer or teacher in a classroom, conference or boardroom. Alternatively, particularly when the character is less experienced, they could be the one attending the lecture, class, conference or boardroom.

Compare ChekhovsClassroom. Both use TheLawOfConservationOfDetail in a way but since {{Exposition}} is used to set up and frame the situation throughout the plot, this trope will emphasize the importance of the scene more while the ChekhovsClassroom will often be presented more as background. Also, Lectures as Exposition often tell the viewer things they need to know ''immediately'' or things they needed to know two scenes ago.

For similar tropes, see {{Infodump}}.
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!!Examples:

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[[folder:Anime & Manga]]
* In ''{{Mnemosyne}}'', some BackStory about the Tajimamori and the "Fruits of Immortality" are filled in during a lecture at Mishio's high school. Notably, the lecture is on the topic of legends and myths but turns out to consist of [[AllMythsAreTrue pretty accurate truth]].
* Subverted in ''Anime/NeonGenesisEvangelion'': it turns out the teacher's expository teaching is [[spoiler: the government's cover-up version of the backstory]].
* One entire episode of ''[[RODTheTV Read Or Die the TV series]]'' is devoted to a character writing the Exposition Lecture that another character has to give.
* Chapter 5.5 of ''Manga/CentaurNoNayami'' is about a teacher giving a primer on [[VertebrateWithExtraLimbs how evolution went]] on this AlternateUniverse, giving birth to the [[OurCentaursAreDifferent various]] [[OurMermaidsAreDifferent human]] [[FaunsAndSatyrs sub]]-[[WingedHumanoid species]] and how this made racism even a worse problem than in our world.
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[[folder:Films -- Animated]]
* Milo gives two lectures on Atlantis in ''Disney/AtlantisTheLostEmpire''. The first one is actually his rehearsal for a proposal to his superiors, which he never gets to give due to them suddenly changing the time that makes it impossible for him to make the meeting.
** He later attempts to give a lecture to the RagTagBunchOfMisfits with a slideshow and some plumbing metaphors, only for some of his vacation photos to get mixed in by mistake. "Hubba-hubba!"
* ''Film/HowToTrainYourDragon'' begins with one. In the space of a 5 minute lecture, Hiccup introduces himself, the other villagers, and the different species of dragon while at the same time sounding almost like a tour guide.
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[[folder:Films -- Live-Action]]
* OlderThanTheyThink: This trope shows up in ''Film/DasTestamentDesDoktorMabuse'' by Creator/FritzLang from 1933.
* ''Film/TheRite'' has Father Lucas explaining the basics of exorcism in lectures at the beginning of the film.
* In ''{{Knowing}}'', Nicholas Cage's character gives some basic information about the sun and the fate vs. free will philosophies during his college lectures.
* A class presentation but one not from a teacher, Sam attempting to sell his stuff at Show and Tell in ''Film/{{Transformers}}'' when told to give a lecture on his ancestors as part of his grade. However, he is distracted by Megan Fox doing that weird thing she does with her teeth.
** In ''Revenge of the Fallen'', Sam has a "full-blown meltdown" in the middle of the first day of astronomy class, and ends up [[MotorMouth babbling at breakneck speed]] about [[ChekhovsGun various things]] that become important later on in the film.
* This is how we learn the main complication in ''Film/GiveMyRegardsToBroadStreet'' -- in a board meeting.
* Jean Grey at the beginning of ''Film/XMen1''.
* ''[[{{Firefly}} Serenity]]'' starts out with one of these (a teacher giving a history lecture to a group of young children).
** It isn't clear from the very beginning due to the matryoshka-doll-like {{Framing Device}}s at work, though.
* ''Film/{{Stargate}}'' opens up with Daniel Jackson giving a lecture on why he believes the ancient Egyptians did not build the great pyramids. The people listening to him all walk out at the ridiculousness of the theory. In a radical plot twist that surprises no one, he was right.
* ''TheFinal'' opens with a {{high school}} history teacher describing how [[ImperialChina the Han Dynasty]] would sometimes [[CruelMercy leave their defeated enemies alive, disfiguring them]] in order to serve as an example to those who would oppose them. Guess what a group of pissed-off teen outcasts do with this knowledge...
* ''Film/UrbanLegend'' tells us about, well, {{urban legends}} by means of a lecture given in a college classroom.
* ''[[Film/TwentyOne 21]]'' has Kevin Spacey's professor character tell us about the GameShowProblem during a lecture. He is an MIT professor after all.
* {{Subverted}} amusingly in ''Film/IndianaJonesAndTheLastCrusade''. Dr. Jones is showing giving a lecture on archaeology, but he merely makes the point that archaeology is not about journeying to exotic lands and following ancient maps to lost cities, "and X never, ever marks the spot." Since this is Indy, however, he [[AdventurerArchaeologist definitely does not go on to practice what he teaches]]-- and he even references the lecture later with a wry grin when it turns out that [[XMarksTheSpot X does mark the spot after all]].
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[[folder:Literature]]
* In DanBrown's book ''TheLostSymbol'', Robert Langdon lectures his symbology class on the secrets of Freemasonry.
* The ''Literature/HarryPotter'' series occassionally uses these (in addition to [[ChekhovsClassroom Chekhov's Classrooms]]). For instance, Professor Binns' ([=McGonagall=] in the movie) retelling of the Chamber of Secrets legend and Moody's demonstration of the Unforgiveable Curses.
* In ''TheNameOfTheWind'', this tends to be the way the reader learns more about the world. It's occasionally presented as a story or myth, instead.
* ''TheAssassinsOfTamurin'' teaches the reader the history of the ConstructedWorld via a session of the heroine's history class.
* The FunctionalMagic of the ''{{Mistborn}}'' series, allomancy, gets explained to the readers through Kelsier's lessons to Vin.
* In ''[[Literature/HonorHarrington Ashes Of Victory]]'', Honor Harrington has been assigned shore duty as a MilitaryAcademy [[VeteranInstructor instructor]] while she recuperates from ([[MadeOfIron extensive]]) injuries she suffered in the previous two books. We are treated to a number of such lectures, including one where a junior officer mortifies a group of awe-stricken midshipmen by calling Honor's tactics in a recent operation horribly reckless, stating that she only came out alive because the enemy simply wasn't paying attention that day.[[note]]They don't know what the readers know: This junior officer is a long-time friend of Honor's, going all the way back to the two of them being room mates at the Academy. And Honor is more than willing to own up to her own poor judgement.[[/note]]
* A teacher in ''Literature/StrengthAndJustice: Side: Strength'' educates the reader on the history of the city in the form of quite a large {{Infodump}} taking up several pages.
* In Theodore Judson's Fitzpatrick's War, the general history of how the world turned into a post-apocalyptic steampunk Neo-British Empire-dominated dystopia is recited in a verbal exam by the novel's protagonist, Robert Mayfair Bruce. Coincidentally Bruce was shocked to have gotten such an easy topic.
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[[folder:Live-Action TV]]
* On ''Series/RelicHunter'', Sydney was telling her class about a particular Indian tribe's mysterious shift in culture right before she went out and solved the mystery.
* ''Series/StargateSG1'': Jack O'Neill's young clone lectures a class of pilots on the F-302.
** Also the original ''Film/{{Stargate}}'' has as its EstablishingCharacterMoment for Dr. Jackson a lecture he is giving to a room of experts about his theory of the pyramids being made to replicate a design of an older, more advanced civilisation.
* ''Series/BuffyTheVampireSlayer'': Buffy did it in "Hush", where everyone's voices have been stolen. Giles delivers the exposition through transparencies and mime.
* In ''Series/GameOfThrones'', Maester Luwin teaches Bran of the various Houses vying for power in Westeros, which also serves to educate the audience on the matter.
* ''Series/BreakingBad'' gives us a scene where Walter White, a chemistry teacher, describes how energy can either be released gradually and unnoticeably or suddenly and violently... [[spoiler: and in the episode's climax, uses mercury fulminate, the explosive he described in class to successfully threaten a violent drug lord]].
* Happens frequently in ''Series/{{Hannibal}}''. When he's not [[TheProfiler profiling]] for the FBI or getting psychoanalyzed by Dr. Hannibal Lecter, Will Graham is a lecturer on profiling and criminal psychology at the FBI academy. His lectures flesh out the show's backstory or the psychology behind the case of the week, and occasionally provide MythologyGags or {{Foreshadowing}} (i.e. the time he lectures on the killer of the week [[spoiler:to a hallucinatory class, foreshadowing his mental illness]]).
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[[folder:Webcomics]]
* One ''TalesOfTheQuestor'' side story was a classroom lecture about the setting's MinovskyPhysics. (In the storyline, it functioned as the first step in DoingInTheWizard.)
* Thomil of ''{{Juathuur}}'' [[http://oneway.juathuur.com/1/?strip_id=109 shows us how it's done.]]
* ''BobAndGeorge'' [[http://www.bobandgeorge.com/archives/040302c As a flashback]]
* Amical teaches his seedlings magic in ''[[{{Webcomic/Morphe}} morphE]]'' using [[http://morphe.thewebcomic.com/comics/1818817/chapter-2-page-34-pretty-amicals-magic-lecture/ morning magic lectures.]] They serve for exposition, world building and catching readers who do not play World of Darkness up on lore.
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[[folder:WebOriginal]]
* A favorite technique in the WhateleyUniverse, since it's set largely in a SuperheroSchool. We've seen lectures on supersuit design, several kinds of superpowers, strategy and tactics, the (made-up) physics behind this universe, how magical contracts work, and several other things.
* An chapter of Literature/{{Brennus}} is about an "Introduction to Metahuman Studies", providing an {{Infodump}} on superpower classifications. This is [[JustifiedTrope justified]] by the creation of a new superpower classification system, and so the characters, as well as the reader, have to be informed.
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[[folder:Video Games]]
* ''VideoGame/TalesOfSymphonia'' introduces its ClicheStorm plot in this only moderately cliched way.
* ''Gabriel Knight: Sins of the Fathers'' has Gabriel attending a lecture at Tulane University early in the game where he learns some important concepts and terms relating to Voodoo.
* ''VideoGame/GodEaterBurst'' has several cutscenes of Dr. Sakaki briefing the PlayerCharacter, [[{{Keet}} Kota]], and [[ActionGirl Alisa]] on the nature of the Aragami. Justified as the main characters are all new recruits, with you and Kota hinted at not having had much of an education at all, and Fenrir wants to spread around its institutional knowledge so nobody leaves too big a hole if they die suddenly.
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