The episode covering plants features a scene where Wanda gets hit by "white stuff" ejected from a chloroplast that's "gooey and sticky"note it's sugar, thankfully and is subsequently grossed out by the fact that it lands in her mouth before she finds out that she likes the way it tastes. Children's educational television, everybody!
"At my old school, we never got baked."
Adaptation Displacement: The TV show is better known to some than the original books; in fact, a new series of paperbacks went into print based on the TV episodes.
Adorkable: Arnold has a bunch of dorky hobbies like collecting rocks and minerals but is also a neurotic Nice Guy.
Awesome Art: Nelvana does an excellent job streamlining the characters in Bruce Degan's illustrations for animation. The animation itself, while not Disney-quality, is surprisingly fluid and expressive for a public-funded edutainment show.
The scene where the bus takes the kids back in time in "The Busasaurus". Ralphie points out that they just went "rewind!" as people and animals move backwards, complete with volcanos refilling with lava. It ends with the asteroid returning to the sky in reverse.
Cargo Ship: Who's the fandom's number one Frizzle-related ship? Arnold or one of her other students? Someone's OC? Mr. Ruhle? One or more of the producers? Lizzie? No, don't be ridiculous - it's the bus, obviously.
According to Tumblr, Carlos apparently grows up to be the perfect, wonderful scientist who moves into Night Vale and falls in love with the host, Cecil.
Critical Research Failure: In one episode, Dorothy claims that everything in the world is made up of molecules, including the sense of smell. This is false; the only things made up of molecules are called matter, and the sense of smell is not one of them.
In "Out of This World," aired years before Pluto's demotion, the class is rehearsing a play about the solar system where they each play a different planet, but Dorothy Ann is late, so they had to start without her planet... Pluto.
Given that the episode is one big Shout-Out to Star Trek, it's almost eerily prescient that the transformed bus vaguely resembles the NX-01Enterprise.
Launcher of a Thousand Ships: Arnold. He's been shipped with everyone - everyone in his class, Ms. Frizzle, Molly Cule, that guy from the hot cocoa episode (Harry Arm), that girl from the water cycle episode (Tiffany), Janet, Azula...
In Israel, the show was just called 'The Magic Bus' (because school buses are not as ubiquitous there). Unfortunately, 'magic' (or, more accurately, 'acts of magic') sounds a lot like 'drugs' in Hebrew (קסמים ksamím vs. סמים samím, respectively). Cue many jabs from kids who've outgrown the series about the bus adventures being a case of Mushroom Samba.
Older Than They Think: With how enduring the series is as a staple of elementary school classrooms, it can be jarring to learn that the animated series started in 1994 and that the book series started even earlier, in 1986.
Paranoia Fuel: If you're sick, a science class might enter your body in a shrunken bus to find out why.
That One Level: The platforming minigames in the Explores the Solar System computer game all can be fairly difficult, but the Saturn level with Tim is generally agreed by people who have played the game to be the most frustrating one. The level takes place on tiny slick platforms in Saturn's rings that you will almost constantly be sliding off of into a level-wide Bottomless Pit (causing you to start over) until you get a jetpack a few screens into the level. While the jetpack can keep you from falling into the bottomless pit, it also uses up air. Running out of air will also start you over, without the jetpack, meaning you have to navigate Saturn's icy platforms to get it all over again.
The series has gained a large amount of older fans, many of whom grew up with it. It helps that both the facts (for the most part) are still relevant and the characters are interesting. Older fans have been known to revisit the show because of how much they forgot that they had learned in elementary.
Conversely, unlike most shows of its age, the series continues to draw in fans from newer generations, thanks to how a good amount of its factual content is still true today (the only majorly flawed episodes by modern standards being "Lost in Space", largely due to Pluto no longer being a planet as of 2006, and "The Busasaurus" due to new discoveries about dinosaurs), leading it to still be commonly read/shown in elementary school classrooms year after year.
Strawman Has a Point: Wanda has this when telling the class she needs to take Bella her bullfrog back home to keep her safe. While Wanda is portrayed sympathetically for her pet having gone missing, the class reiterates that Bella seems happier in a natural habitat where she can lay eggs rather than staying with Wanda. Wanda retorts that there are natural predators everywhere, so Bella wouldn't be safe. She's not wrong; Bella is completely domesticated, and that tends to put a crimp on survival instincts. Wanda only concedes when she sees that Bella can defend herself, or at least flee from predators.
Trans Audience Interpretation: A theory among the LGBT Fanbase suggests that Ms. Frizzle is Arnold from the future, post-gender-transition. The similar hair, Ms. Frizzle's absolute unflappability, her fondness for pickles... Pickles? Spironolactone, an androgen blocker commonly taken by trans women in the US, is also a potassium-sparing diuretic, resulting in increased thirst and cravings for salt. Pickles solve both of these problems and have become a meme in trans communities as a result.
Values Resonance: This show may have the single best depiction of diversity in any children's series, in that it only depicts it, but rarely if ever addresses it: apart from the multi-ethnic class, we have two canonically handicapped characters with Carlos's paraplegic brother Mikey and Phoebe's blind father, but never uses them for Positive Discrimination, treating everyone's differences as 100% normal.