The Heisenberg Uncertainty Principle was created by an old, German coot named Werner Karl Heisenberg in 1927. In quantum physics, this principle states that we cannot measure the position and the momentum of a particle with absolute precision. The more we try to accurately learn the measurement of one value, the accuracy of the measurement of the other value is lessened.

            In simpler terms, observations have an effect on the accuracy of the measurements, and measuring two things at once lessens the accuracy or certainty of the measurements.

            For instance, the observer, in this case, can be a blind person with a small ball, and the way that the blind person will be able to determine how far away they are from an object is by throwing a ball. If the object (in this case a stool) in the direction which the blind person threw your ball at is near, the ball will bounce back, and they’ll know that the stool is near. If the stool is far away from them, the ball will take time to bounce back, and you’ll know that the object is away.

            The problem of the principle lies in the fact that once the blind person does throw the ball at an object, the ball used to measure the distance between the observer and the object changes the distance between the observer and the object. The stool might move a bit. The stool might fall down. The stool might get knocked across a distance. The observer may be able to tell where the stool was, but they will not be able to tell where the stool is now or how fast the stool moved.

            The Heisenberg Uncertainty Principle rests on the fact that the world is uncertain and that there is a limit to what we can know about the smallest scales of nature without changing anything.

Soomi felt sick.

           Like clockwork, she received another e-mail at exactly 6AM. Luckily, this time, it didn’t cause her to almost walk into traffic; she received it just before she crossed the road. The first e-mail already scared her. The second one terrified her. It had to be a prank—an elaborate prank that some dumb seniors must have pulled with that Do Kyungsoo as an actor. Were her friends in it as well?

            Soomi turned to look at her Chanyeol who was sitting beside her in their classroom and chatting up Jongdae behind him. Was it him? He was known to like pranks and to cause mischief. Would he do something like this to her? Soomi chewed on the inside of her cheek in thought. He did trick her into swallowing a wasabi Kitkat before, right after giving her a jellybean that was skunk-flavored. Is he the culprit?

            What about Jongdae? She turned her body ever so slightly to peer at her friend sitting at the desk behind her and laughing at Hyeri’s joke. Jongdae wasn’t as mischievous as Chanyeol, but he made sure that whatever wrongdoing done to him would be paid back in full. Soomi could still feel the ache in her legs when he dragged her around the mall to help him find and carry suitable clothes after she forgot one meeting that she had with him because she was able to torrent a new documentary series. The tone that he had when he called her to say that he had been waiting for three hours already was one that she would never forget. Would he be that cruel to start this prank?

            Or would it be Hyeri? Her temper had always been an issue. She was quick to spark and was almost on the same level of mischief as Chanyeol was. Hyeri’s version of mischief was crueler, sometimes bordering on shocking. Soomi could remember the time she and her friends were trying to wake Chanyeol up so they could all go to a party, and Hyeri dumped a bucket of water over Chanyeol, not only soaking their tallest friend but also soaking his bed and the comic book stash under his bed.

            And Jongin? Would Jongin do something as elaborate at this prank? Soomi spied at her friend sitting in front of her and Chanyeol.  Just like Hyeri, his brand of mischief sometimes bordered on cruel. There were times where Soomi caught Jongin tripping Sehun and Chanyeol while playing basketball. The sound of their knees hitting the floor was followed with curses from both boys.   

            Soomi shook her head to dispel those nasty thoughts. Of course her friends wouldn’t do that to her. Whatever this prank or game was, it was simply cruel. Though her friends have their own brand of mischief, they wouldn’t go this far. At least, that’s what she tried to remind herself.

            So, who? Why? How?

            There were so many questions that persisted in her mind and made her stomach uneasy. With a deep breath, she brought out her phone from the secret compartment under her desk. The first e-mail in her inbox from her again—or well the “her” from “the future.”

August 29, 2017- Second Week of Classes > [Inbox]

From: me [sm.choi049@ hanmail.net]

To: me [sm.choi049@ hanmail.net]         

          Have I captured your attention yesterday? Please believe that everything I write is true, from the events to my feelings about the events. I hope that I have convinced you enough to heed my warnings and to follow my favors.

          Tired today, huh? You probably should calm down with the documentaries late at night. Your friends are right that it’s not healthy anymore.

          Anyway, this time, let me tell you what happened as I remembered it. I don’t have all of the answers to all of the questions that I had on this day, but maybe it’s because of the one action I did not do.

Please. Please don’t do what I did.  

            “Hey, are you okay?”

            Soomi blinked and turned her head to face her seatmate. “Uhm, yeah. Yeah. I’m fine, Chanyeol. Why?”

            “You look a bit sick,” Chanyeol pointed out with a worried frown. He reached over and touched the back of his hand to her forehead. “Actually, you’ve been looking a bit pale since hagwon yesterday. You okay?”

            Soomi quickly moved away from Chanyeol’s hand, knowing full well why she looked sick. Her lips felt dry when she them. “I’m just a bit tired. I wasn’t able to catch sleep easily last night.”

            “Are you sure it wasn’t because of a new series?” Chanyeol teased, grinning and nudging her side.

            “Why don’t any of you have any faith in me?” Soomi asked in mock hurt. She let out a laugh, though it sounded a bit forced in her ears. “Say, Chanyeol, if you received an e-mail claiming to be from the future, what would you do?”

            Chanyeol furrowed his brows, looking absolutely puzzled at her question. “An e-mail…from the future?”

            “Just hypothetically,” Soomi said hastily, anticipating his answer.

            Chanyeol hummed and scratched the back of his neck in thought before answering, “Hopefully, it’s an e-mail about lottery numbers so I’d get rich.”

           “Chanyeol, I’m pretty sure the e-mail that you’d receive would just say ‘Don’t be stupid’ or probably an article about some disaster that you caused,” Hyeri chimed in from behind the two.

            Soomi almost jumped in her seat when she heard Hyeri’s voice. She wasn’t expecting the girl to be listening, seeing as how she was content with her conversation with Jongdae earlier.

            “Thank you for your faith in me, friend,” Chanyeol jested, rolling his eyes playfully. “And that’s really hilarious. You should be a comedian. I’ll be your number one fan.”

            Hyeri snorted, rubbing her nose with the back of her hand. “Eew. I don’t want you as my stalker, Chandork. I’d at least want someone easy on the eyes.”

            “Excuse me?” Chanyeol shrieked, placing a hand on his chest to feign hurt. “I am easy on the eyes! I—I am the easiest on the eyes! You won’t find anyone else easier!”

            Soomi, Hyeri, and Jongdae (who was casually listening in) burst out laughing at the comment. Soomi covered her face with her hands to stifle her laughter, Jongdae pounded his fist on his desk, and Hyeri simply let out a boisterous laugh, a hand wrapped around her stomach.

            “You idiot! That doesn’t make any sense!” Hyeri said in between laughs, pausing at the end to wipe the tears from her eyes.

            Jongdae waved his hand dismissively at Chanyeol and asked, “How—How do you fit through the door with your big head?”

            “I learned to walk sideways,” Chanyeol answered with a big grin and a wink at Jongdae, earning more laughter from his friends.

            Soomi shook her head, laughter still bubbling on her lips. She turned to Jongdae, twisting in her seat, and was about to ask him about e-mails from the future when a yawn escaped her lips instead. Jongdae raised a brow at that and chuckled.

            “Are you sure you’re okay?” Chanyeol asked, brow raised as well.

“Yes.” Waving her hand dismissively, she emphasized, “Really, I’m just sleepy.”

            In actuality, the lightheaded feeling rushed back to her, and her eyes watered from the yawn. 

            “If you say so,” Chanyeol said, though he didn’t look convinced. “You should have taken a nap once break started. Now, you don’t have enough time before—“

            “Everyone to their seats,” called out Mrs. Kim, their English teacher, as she entered the room. Her heels clacked on the floor in time with the sway of her ponytail. “Pull out a fresh sheet of paper! Pop quiz!”

             Most of the students in the classroom groaned as they, like clockwork, made their way to their seats. There was the sound of shuffling papers and murmurs around the room as everyone got ready to take the quiz. English was easy for Soomi. It did help that some of the documentaries that she watched before were in English. She had to keep pausing throughout watching it to search certain terms or words that she couldn’t understand. Her determination to understand what she watched paved way for her to develop her language skills. English translation of Korean sentences? Easy enough for her now.

            When the actual lesson started, Soomi tried her best to listen to the discussion, though there were times where she had to stifle her laughter after seeing Chanyeol make faces at words that he either could not understand or could not pronounce properly. He would try his best to pronounce them under his breath, but he had to stop when he pronounced “complain” as “compreen” and Soomi almost died from trying to stifle her laugh. The hardest part for Soomi was keeping her eyes open and her attention away from how nice it would feel to lay her head on her desk. As the clock continued to tick—far too slow in her opinion—and her teacher continued to drone on, she could feel herself getting lightheaded again. It was a funny feeling. It felt like her head was full of cotton balls or like it was slowly filling up with water. How nice it would be to lay her head on the desk to make sure she wouldn’t drown.

            ‘Bang!’

            Soomi jumped in her seat, eyes wide, as she felt a dull ache on her forehead. There was a sharp silence in the room as she tried to remember what happened. One moment she was staring at Mrs. Kim as the teacher wrote “complaint” on the board, and the next thing she knew it turned dark before she heard the loud sound—oh.

            The students around her started laughing, and that made blood rush to her cheeks. Chanyeol was nobly trying to hide his laughter