74 - The Atomizer
Fourth period ended, and lunchtime arrived. Along with Seri and Yuna, who were growling at each other, we lined up at the cafeteria with Ji-hye in tow. Everyone was buzzing about the practical evaluation from that morning.
Ji-hye clapped her hands together with a smack.
“Your class had a number competition too? Ours had a record high of 9.3.”
“It was so close, Ji-hye! I broke 9 at the very end!”
“So who got first? Nami, right?”
“Ahem...!”
“...?”
Yuna lifted her chin proudly and snorted. Seri shot her a sharp glare.
“You only got that because Nami helped you.”
Since second period ended, Yuna's elevated energy hadn't died down one bit. Seri, already briefed on the details once, relayed it all to Ji-hye just the same.
“But injecting mana that precisely is super hard!”
“Yeah, yeah, you're amazing!”
“But how'd Nami figure out that number?”
The model magic circle's structure went beyond elementary curriculum—maybe even middle or high school level. It was natural for Ji-hye to wonder.
“The one we got satisfied the harmonic mean. North optimal was 150, south was 200, so overall around 171.42.”
“What's a harmonic mean?”
“Hmm... how to explain.”
The arithmetic mean of the reciprocals, then reciprocated back? That'd confuse her. Better to use simple numbers.
“What's the average of 1 and 1/3?”
“Umm... ugh... I kinda know, we learned it, hold on!”
Ji-hye wracked her brain before squeezing out an answer.
“3/3? No, that's 1! 2/3?”
“Ooh, smart girl!”
“Aah, you knew and just teased me!”
She swatted away Seri's hand stroking her head.
“Harmonic mean's calculated like this. Answer one by one. Reciprocal of 1?”
“1, obviously.”
“Reciprocal of 1/3?”
“3?”
“Average those two.”
“Easy. 2!”
“Now reciprocal that.”
“Umm... 1/2?”
“Right. That's the harmonic mean. Got it?”
“No, I don't get it at all!”
I thought I'd explained it simply. Guess I'm no good at teaching kids. If basic math's this hard, how am I supposed to teach Adella later? No clue where to start.
Anyway. We got our lunches one by one and grabbed seats in the farthest corner of the cafeteria. Seating was always the same: Seri next to Ji-hye, Yuna next to me.
“Waaah, bulgogi looks so good.”
Yuna beamed as she set down her tray. Thankfully, today's haul was piled high with rice and meat sides.
“You're only eating that much again? Want some of my meat?”
“I'm good.”
“Eating so little could make you sick later.”
It's because I'm sick that I can't eat more. Hoping Professor Cheon brings good potion news soon, I popped some bulgogi in my mouth.
Unlike her usual nonstop chatter, today's vibe was quiet. Seri and Yuna's eyes darted around, probably mulling over the harmonic mean I'd explained. While Seri kept trying to grasp it, Yuna—who seemed to get it—asked me next.
“I get the math. But I still don't know what that coil spell does.”
“Curious about the coil spell, Yuna?”
“N-no... uh, yeah, actually I am. Tell me...”
Yuna bowed her head and asked first for once. She usually hated admitting what she didn't know. Guess she really wanted to understand that spell.
How to explain simply? Words had limits.
“I'll show you later when I take my potion.”
Nothing beat a live demo.
* * *
Equations and theory are just extras for explaining magic. To truly get it, you need intuitive observation of why the phenomenon happens.
I led Yuna to the back yard. Right by the fence between middle and elementary sections, I set down a potion bottle from class.
“Why here?”
“To show you magic.”
“No one's around... kinda creepy.”
The back yard, unlike the front garden, was overgrown with weeds, adding to the eerie vibe. But that's why I picked it—no foot traffic.
“Got a spare pen you're not using?”
“Yeah, this one's broken.”
I emptied the 4-color ballpoint, leaving just the plastic shell. Prep complete.
“The model you saw generates heat via an electromagnet coil. Not exactly the same, but I'll recreate something similar.”
Before uncapping the potion, I etched the magic circle's outline on the ground. Looks alone wouldn't explain it, but now I'd channel my inner star teacher and break it down easy.
“This is a coil—wire wound in loops.”
“I know coils! Learned in first-grade science.”
“Nice, easier then. This part's the formula to make current flow through the coil.”
“Current?”
“Electricity.”
“Makes electricity flow? Why?”
“Current in a coil makes heat.”
“Coil gets hot?”
“Yeah, super hot.”
Skipped voltage, current, resistance details. Common sense that current heats the coil was enough for now.
“What if water gets hot?”
“Umm... hot water?”
“Hotter.”
“Steam!”
“Right. We're turning liquid to gas with coil heat.”
Heat Transfer - Coil
First, etched the base circle on the ground and linked it to the pen. Skipped the electromagnet complexity, modded for standard current supply.
Added a pointer transmutation circle inside the pen to follow the etched principle.
“Imagine a tiny coil inside the pen now, Yuna.”
“Okay.”
“Drop potion on a hot coil—what happens?”
“Potion turns to smoke? Or... coil cools?”
“Can't let it cool, so cotton in the middle. Drip potion drop by drop onto it.”
“Then smoke!”
Yuna nailed it; I nodded. Uncapped the potion, shoved the pen into the flask mouth. Sealed gaps with leftover modeling clay from art class to prevent residue oxidation. Ridiculous shape, but best way to demo.
“Core's resistance. Watch. Inject mana here—total resistance 0.5 ohms.”
Tap tap—activated the engraving. Ground circle glowed; I put pen end to mouth and inhaled.
Potion soaked cotton, instantly vaporized by hot coil into steam. Pen to mouth, mouth to throat, throat to lungs. Exhaled—and pale smoke billowed out.
“Fuuuu...”
As expected. Vaporized potion tasted less bitter. Nebula-state mana sticks in the body once inhaled, efficiency matching liquid intake. Why hadn't I thought of this before? Life lesson: creativity's essential.
“Woooah! How, Nami?! Smoke from your mouth!”
“Double resistance this time? Double smoke.”
“More than this?”
Yuna's excitement lifted my mood too. Set resistance to 1 ohm, inhaled again.
“Fuuuu...”
“Waaah, smoke! *cough cough*... Ugh, bitter.”
Twice the smoke; Yuna waved it, inhaled some, coughed.
“Don't try inhaling on purpose. Tastes awful. Why, wanna try?”
“I nearly died choking last time...”
Yuna shook her head hard. Fine. Before fifth period, I puffed hard to finish the rest. Yuna, watching the circle, muttered.
“Looks just like cigarette smoke.”
“You're so smart, Yuna.”
“Huh?”
“Same principle as a cigarette.”
“What?”
Exhaled the last puff, done with lunch dose. Engraving lasted long, but twenty uses max—no more heat.
“This is an atomizer—vape device.”
Kids these days don't know vapes?