I have to thank everybody because, really... I didn't expect to get this amount of requests! xD

Well, this first chapter is for: walestm

Enjoy! :D

"So, when it comes to the reaction rate or speed of reaction, however you want to call it, for a reactant or a product in a particular it is defined as how fast or slow a reaction takes place." Said Taeyeon as she stood in front of the class. 

She looked around and sighed, it was obvious that most of her students were ignoring her.

She had to do something to attract their attention or they were going to fail this month's evaluation, again. Normally she wouldn't care about it, it was their fault for dozing off while she was busy explaining what they would need for the test, but it seemed like she had gotten a bunch of whiny students this school year so whenever they failed, they went home with their parents and blamed it on her, then all of their parents would call the school, call her a and she would get scolded for doing nothing but her work. For doing the right thing.

She sighed soundly this time. She didn't want to get any of that again, she's had enough of it for the past few months. 

"Has anyone heard about this before?" One of the students who were actually paying attention to her, JooHyun, raised her hand. "Anyone else?" Silence welcomed her as she asked once again. "Then I don't seem to understand why most of you aren't paying attention," She stated, clearly mad. 

"Of course only our Seohyunnie would know." Taeyeon heard Yoona, the class clown, say loudly. "She's perfect." She smiled weirdly. "A nerd, but perfect still."

Suddenly the class was filled with wooing and giggling. Joohyun was blushing and Yoona was smiling stupidly, this made Taeyeon grin.

Yoona had a huge crush on Seohyun, it was no secret, she always made flirty yet teasing comments throughout class, though, when she paired them together, Yoona wouldn't utter a word. She was too shy to actually do anything. 

"Yeah, a total nerd." Another voice was heard from the other side of the classroom. 

The class errupted in laughter and Seohyun's expression faultered slightly, Taeyeon knew what was going to happen now, it was always the same whenever someone who wasn't Yoona made fun of Seohyun.

"Yah!" Exclaimed Yoona while standing up from her seat. "You want to die?!" 

Taeyeon closed her eyes and massaged her temples as she heard the troublesome student continue to "protect" Seohyun, making the whole class roar in laughter, yells, teasing, etc. etc. 

"Yah!" She screamed, not being able to tolerate the noise any longer. "Be quiet or I'll take points off from your exam." 

Once again the room became silent and Taeyeon sighed, teaching high school students wasn't an easy task after all. 

"Well, as I was saying, the reaction rate of a particular reaction can be defined as how fast or how slow the reaction will be," She repeated. "And this is related to collision theory, it states that when suitable particles of the reactant hit each other, only a certain percentage of the collisions cause any noticeable or significant chemical change; these successful changes are called successful collisions. The temperature, the concentration and the orientation are factors which are very important when it comes to obtaining a succesful collision and could even affect the reaction rate, which is why they are related..." She noticed more students were paying attention as she continued to explain the factors, though most of them seemed puzzled. 

Suddenly, a hand was raised, it was Sooyoung, the girl who was always next to Yoona. 

"Yes, Sooyoung?" Said the teacher.

"It's just that..." Sooyoung blushed, not accostumed to say her questions out loud. "I understand the influence of temperature and concentration... but... why orientation?" She asked, other voices were heard in the classroom, agreeing with her.

"Ummh..." She wondered, thinking of a trivial way to explain it so they would understand properly. 

She looked around the room, only to find Yoona staring dreamily at Seohyun who was staring intently at the teacher. 

An idea popped into her mind and a smirk appeared on her face as she figured one of her students will probable love her from now on. 

"Ok, I need two persons for the following explanation." Said Taeyeon seriously. Many students raised her hands, she noticed Seohyun slowly raised her hand and the moment it was fully in the air, Yoona's hand was automatically raised. She chuckled a little at it. *Sigh* This lovesick kid. "Okay, Yoona, Joohyun, come over here." 

As she saw Yoona's eyes turned bright and a big alligator smile crossed her features, she smiled, even brighter as she noticed Seohyun turn red as they approached the front part of the class. 

Once again the rest of the students started wooing, most of them cheering for Yoona, who seemed a bit shy as she stood next to the younger girl.

"Please be quiet, I need you to pay attention to this." She said carefully, "Now, Yoona, on my right facing Seohyun, Seohyun, on my left, facing the door." 

The two girls nodded and did as they were told.

"Now, imagine Yoona and Seohyun are reactant particles,"She stated, feeling herself smile as she thought of what she was going to say next. "And the reaction would be them hugging." She saw Yoona's wide doe eyes turn even wider and noticed how Seohyun's ears turned red. "But for the hug to occur properly they need to be facing each other, so if Yoona," She took ahold of Yoona's shoulder and pulled her. "Goes over to Joohyun and hugs her," She pulled Yoona until she was touching Seohyun's back with her front. "The hug is not occuring properly." She pulled Yoona back a little. "Joohyun, turn around." 

Now the students were facing each other, she noticed her other students were all staring intently, for once paying full attention to the lesson. 

"Now, Yoona and Joohyun. Please hug." She said. 

Yoona's face turned the brightest red she has ever seen and she felt like laughing like an ajhuma at the poor girl, but she knew it wouldn't be most teacher-like reaction she could have, so she stayed calm as she stared at her student. She heard a sigh coming from the taller girl, making her whip her head in that direction.

What happened next was something she didn't expect to happen. 

Joohyun had leant forward and wrapped her arms tightly around Yoona's waist. There were gasps coming from all the other students and Yoona inmediatly wrapped her arms just as tightly around Seohyun's neck. 

Taeyeon smiled, she felt like a shipper now. 

"So as you can see, after Joohyun changed her orientation it was possible for them to hug properly. So if Joohyun had been facing Yoona since the start, it would've taken less time for them to hug." A collective 'ooh' was heard in the classroom and she was surprised at how it seemed like everyone in the room had payed attention to her this time and had understood what was going on, she noticed how Yoona and Seohyun had finally let go of each other, their faces showing clear embarassment. And she smiled.

Maybe she should use them for more examples later on.

Ta dah! First request done (y) Hope it filled your expectatives and that it was okay :3

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The next update will be YulSic :D

Until Next Time :D