Pay attention in class, especially science class, because you will need the information later in the episode.
This trope is the awkward tendency of programs to use precisely what they learned in school (almost always science) earlier that episode, and to lampshade it through grating dialogue. Shows aimed at an older audience can make it slightly more subtle; even so, it usually comes out like this:
"Oh yes, I totally forgot. How conveniently stupid of me!"
- Anime & Manga
- Live-Action Films
- Live-Action TV
- Video Games
- Web Original
- Western Animation
- The Arithmancer universe: Ancient Runes class is surprisingly helpful at driving the plot, especially in The Arithmancer (as well as Lady Archimedes regarding the ritual to take down Voldemort).
- In the first two years at Hogwarts, Professor Babbling teaches various younger students, this time including Harry, Ron, and Hermione, to carve runes into wooden blocks during seminars. This helps Hermione to create, with Ron's help, wandless potions kits that even muggles can use, using wood-block runes to provide the magic required for the brewing process. It is used again in Chapter 57, where Ron carves runes to be charged with fortification spells to delay Professor Lupin from breaking out of the Shrieking Shack as a transformed werewolf. This manages to hold until the group reaches Dumbledore for help.
- Later in the book, Professor Babbling teaches the Bliviklet spell to her third-year class to link runes together in Chapter 53, explaining its practical application for simple and temporary defensive and monitoring systems. This comes in handy four chapters later, when Ron uses the spell to alert him and the rest of the group the moment werewolf-Lupin breaks out of the Shrieking Shack.
Ron: Entwined pair of runes, remember? They're good for monitoring. When it breaks, we'll know Lupin got out.
- In the Teenage Mutant Ninja Turtles (2012) fic A Day Without Leonardo (AO3 link here), Splinter gives the remaining turtles guidance on being a leader and working together during the first chapter's training. All of his advice is later put to use in the second chapter when the turtles go up against a gang of Kraang.
- Abram, the victor who only scored a 3 in The Victors Project, won his Games because of this. He spent his entire time in the Training Center at the edible plant station because no one would bully him there. It came in handy in his Thirsty Desert Arena.
- The Dethklok song "Bloodrocuted" has the protagonist come up with the idea of using his own blood to electrocute his pursuers after having a brief flashback to his high school biology class, where he learned that blood conducts electricity.
- In In Strange Woods, while Lexy stops going to survival training after John Francis breaks his wrist, she takes what she learned to heart. She uses examples of dead reckoning and other things Howl taught to make a case for sending a search-and-rescue team in the final episode when the adults assume the kids would be fine.
- Katawa Shoujo has this in Emi's route. Mutou, Yamaku's science teacher, takes Hisao aside for a short lecture about observing things (if you let him). Namely, that if you can't observe something directly, observe its effect on other things. This advice comes in very handy, as it unlocks new dialogue options when Hisao and Emi's relationship starts getting off-track.
- Foreign language courses if you ever use them. NOT having language skills is not only inconvenient, but downright dangerous, especially if you ever have to deal with security forces or even just toughs.
- Except when the security forces become suspicious because your foreign language skills are better than they would expect.