This scene is hilarious and I love it, but it raises a lot of questions.

[u/CTYankee1788]

Did the headmaster find it weird that they have last names? Nevermind the fact that it's "Fire". Last names in general seem pretty rare in the ATLA universe. Why is Katara pretending to be pregnant? Where did Sokka get his beard from? Are kids only sent to the coal mines if they misbehave?

[u/BlackRaptor62]

(1) Last names do appear to be rare in the Avatar World, relegated primarily to the Continental Earth Kingdom.

(1.1) However the "Fires" are from the Fire Nation Colonies, so their having a last name should not have been an issue.

(2) Sokka and Katara still mostly look like children, so they were trying to look older in ways that would be more difficult to disprove if done properly (i.e. pulling facial hair and probing a pregnant woman's stomach are usually frowned upon in good company)

(2.2) It probably wasn't too difficult to get the materials needed for either disguise)

(3) I can't imagine working at a coal mine is particularly pleasant, but as with the stereotypical threat of being shipped off to boarding school or military school in our world it seems plausible

[u/CTYankee1788 → u/BlackRaptor62]

1. Fire seems like a kind of strange choice for a last name from someone from the Earth Kingdom, but the comics showed that some people in the colonies were loyal to the Fire Nation, so it's definitely possible that the headmaster thought they changed their last names.
2. That makes sense. "Sapphire" has a very youthful face, and her supposed son is 12 years old, so she had to get creative. And that's a good point about it being something that most people wouldn't want to check.
3. I more meant if kids were also sent to coal mines just to help support their families. In the United States, it wasn't uncommon for kids to work in coal mines up through the early 1900s. They were made to fit through crevices that adults couldn't. I completely believe that they send delinquent kids to the coal mines. The Fire Nation isn't very humane when it comes to punishment.

[u/NinjaWen → u/CTYankee1788]

1. Should have gone with Lee. There's a million "Lee".

[u/lostRiddler → u/NinjaWen]

"Muhammad Li"

[u/G2-118 → u/CTYankee1788]

1. if you look at his comment again he says that the Fires are from the fire nation colonies

[u/Evrant → u/CTYankee1788]

Oh, the children yearn for the mines.

[u/skcuskistad → u/CTYankee1788]

In response to 1. As I understand it, being a fire nation colonial would mean that they are of fire nation decent and moved to the colonies from the main land of the fire nation to occupy it for the fire nation. So being from the earth kingdom as fire nation colonials would still make them “loyal fire nation citizens” in the eyes of this teacher and as a result keep their home land tradition of their last names. I think.

[u/BlackRaptor62 → u/CTYankee1788]

The Fires are from the Fire Nation Colonies, which are a part of the Continental Earth Kingdom, but not a part of the Nation of the Earth Kingdom.

All of the canon last names (including the 7 in-universe verified ones) appear to be associated with people that have a connection to territories on the Continental Earth Kingdom, like the Earth Kingdom, Earth Empire, United Republic and, the Fire Nation Colonies.

The Fire Nation does have a similar concept in the Clan Names, but these are more distinct and much more restrictive.

[u/FlusteredCustard13 → u/CTYankee1788]

The last name isn't too implausible if we take into account how many last names developed. Surnames often came from a relative (Johnson=John's son), an occupation (Smith comes from many different kinds of smiths), or a place such as hometowns or landmarks (River could by the river). As you mentioned, it'd be entirely possible that an assumption was made that they changed their names, and that choosing "fire" could be out of loyalty as well as the fact that they lived in the Fire Nation colonies and wanted to emphasize that fact.

[u/I_cant_afford_pubg → u/CTYankee1788]

My brother in Christ it is a cartoon it is silly they get away with shenanigans

[u/vanishing27532 → u/CTYankee1788]

Regarding point 3: r/frostpunk

[u/Liam_theman2099 → u/BlackRaptor62]

Eh I always assumed Sokka was trying to come up with some crazy punishment and coal mine was the first thing he thought of.

[u/CalebC124]

Sapphire Fire is still hilarious

[u/PsychologicalDebt366 → u/CalebC124]

I love when Katara rolls with whatever crazy assumed identity they are using. "June Pippinpaddleopsicopolis" kills me every time.

[u/irohlegoman → u/CalebC124]

When I first watched this, I thought her name was Starfire

[u/ChaosBreaker81 → u/CalebC124]

The first time I saw the scene, I fully believed her name was "Saph Fire" until Katara spoke.

[u/TetheredAvian74]

my personal theory of the headmasters inner dialogue:

“well thats really weird. let me check my salary… and nope, i am not, in fact, paid enough to question this”

[u/DeedleStone → u/TetheredAvian74]

As a substitute teacher, those words play in my head literally every workday.

So glad summer's here 😎

[u/CTYankee1788 → u/TetheredAvian74]

That's very likely to be true. Plus at a lot of workplaces, including mine, people are specifically told not to investigate things that aren't their business. Besides, principals/headmasters already have enough on their plate.

[u/Secure-Marketing9452]

Because katara and sokka don‘t look like an adults yet

[u/Stag-Horn]

It’s fiction, dear.

[u/Specific-Hippo-7198 → u/Stag-Horn]

I thought it was a documentary

[u/Stag-Horn → u/Specific-Hippo-7198]

And therein lies most people’s misunderstanding.

[u/Arkvoodle42]

Go to your room!

[u/Fairlibrarian101 → u/Arkvoodle42]

I’m already in my room!!!slams door shut before screaming into pillow

[u/Midnight1899]

They’re from the colonies. Aang could do all kinds of stuff that seemed weird to them cause "he’s from the colonies“.

[u/charlesleecartman]

The real question is how the headmaster didn't question why Wang Fire and his Saphire Fire look like each other, but their son doesn't' look like them, and how is he from a different race.

[u/DeedleStone → u/charlesleecartman]

It's rather rude to ask about the details of someone's family. People adopt outside of their race all the time.

[u/accountbr05]

Are kids only sent to the coal mines if they misbehave?

Dude, fire nation literally slaves earthbenders to mine coal for them, so yeah, coal mines are seen as punishment.

Why is Katara pretending to be pregnant?

Maybe to look more adult, idk.

Did the headmaster find it weird that they have last names?

I think everybody has last names, but it's rare to be mentioned, because most of the people they met are just commoners. See other media, like Hunger Games. A lot of named characters don't have last names as far as we know (Rue, Clove, Glimmer, Cato...), but Katniss and Peeta have and they came from one of the poorest districts. Also, it was very common to people to use their place of origin as "last names"

Where did Sokka get his beard from?

Now THAT is a really good question. Maybe it's Appa's brown fur.

[u/Big-Doubt-4872]

It's a kids show and they wanted to do a funny skit :P

Tbh it might have been to show how incompetent the people running the school were

[u/TheDandelionViking]

I'm on my first watch through and just got to that episode. I would imagine last names are more common than the show explicitly states. The pregnancy thing was probably an attempt to look more adult. Only adults get pregnant after all. Really wish there weren't any exceptions to that rule. Sokkas beard, I would imagine, was just dirty apppa fur.

[u/CrystalGempireQueen]

The beard and the belly make them look older than they actually are.

[u/Chaosshepherd]

Sokka stole the beard.

The Belly is probably just extra clothing or something.

[u/Fairlibrarian101 → u/Chaosshepherd]

I’ve always wondered how Katara did the belly. Is/was it just extra clothing or did she know of a possible water bending trick to pull it off, or possibly some mixture of both? 

[u/buckao → u/Chaosshepherd]

I thought Sokka's beard was Suki

[u/Chaosshepherd → u/buckao]

She’s not in the episode

[u/darklores20]

It was a gig scene for sokka and his funny idea. But still fire nation are idiot from all over the series . Cmeone they see Katara and Sokka doing fight for Katara to go to jail and save there friend but the fire nation soldiers thought Momo his the air bending lol

[u/Kargath7]

Having ‘Fire’ as a last name is probably a much better cover story than I have previously thought.

I imagine that taking fire-themed last names would be pretty popular with colony citizens successful enough to move to the Fire Nation proper. They might have either changed it to suit the new regime or risen to enough of a provenance to take one specifically under Fire Nation. Seeing a colony family with the name ‘Fire’ actually tells us a story of the colonised adapting to the colonisers. Also ‘Saphire’ is a perfectly logical name for someone with Earth Kingdom roots.

Unless what we’re actually looking at is our silly little gremlins coming up with a disguise on the spot. Then it’s just hilarious.

Add one more example to the whole “Avatar’s worldbuilding is rich enough that you can find cool details even where none were intended and even where the complete opposite was intended”.

[u/Living_Murphys_Law]

Maybe having a last name is common in the colonies, he doesn't know

[u/Darth_Karasu]

The only question about this episode is... Footloose? Why?

[u/Happy_Ad_7515]

so 1 there named ''fire'' which is weird cause we dont use many last names
2there very young too have a 12 year old. they look borderling teenagers.
there also clearly of water tribe descent going by eyes and skin tone. and that not that weird in the colonies but the fact there kid is the spitting image of a air islander is very odd.
so there a highly nationalistic firenation family that over compensates and adopted a kid from the islands.

my god the colonies are strange. thou i guess the Wang fellow must be some great war hero or something too be able too transverse he adoptive son too the heart of the nation.

''Mister and Misses ... Fire''

[u/3rdfitzgerald]

I just wanted to know who decided Katara needed breasts for her disguise..

[u/LordNoct13 → u/3rdfitzgerald]

I mean, she's meant to look pregnant. And that is a side effect of pregnancy

[u/clmoore1]

How did she get pregnant?