He opens the book, flipping through the pages he's read through with so many classes he can't remember.
"Alright," He places his finger on the page and looks up at the thirty students sitting before him. He'd been surprised by how many young adults had opted for sciences when the fashion these days was humanities. Through previous years not many had shown an interest towards studying the science of matter and reactions although he supposed parental desire has played a bit of a role in the decisions. He could only hope that the students themselves would find a personal joy in chemistry.
Little did he know that the rumour wasn't about the popularity of the subject but the popularity of its teacher.
"Page thirty four. Please start reading, Songdeuk."
He congratulated himself for remembering the name of the student. It was harder than he'd assumed at first, trying to remember the names of thirty different children. And it was a new batch every year too.
The teenage boy seems to look a little lost, before he finds the section. His reading isn't that fluid, but it was a difficult chapter with many new words. On top of it, he was trying his best and Namjoon appreciated that.
He looked out the window. It was close to lunch time, the time when the sun shine the brightest and all of nature lit up in its warmth. It was the time he would like to go outside into Seoul and take a walk along the Han river.
But instead he was here.
He didn't mind it. Teaching, as enduring and repetitive as it was, was providing education to those who held the future in their palms. He found that aspect of his life very interesting. These thirty children who sat in front of him, had immense talents within them just waiting to blossom.
A ray of sunlight streamed through the curtains, casting a shadow across his face. He basked in the sunlight, enjoying the love of nature. It was composed of so many little things, so many tiny quivering bonding chemicals and matter. It was so fascinating in itself. Looking at the sky through the window he found the moon in the sky. It was unusual to see the moon during the day but there it was, almost camouflaged into the sky. He smiled to think it might have come to see him.
He turns suddenly, realising the silence in the class. Thirty pairs of eyes are staring at him as he spaced out into his own fantasies. If he daydreamed how could he blame his students for doing the same?
"Ah," He turns a little pink, embarassed. "Were you done? Now..." He turns to the blackboard, picking up the chalk.
"Changes in atoms." He announces, writing it clearly up on the board. "Atoms consist of protons, neutrons and electrons. However forces between atoms cause them to give and receive. This changez some of their features."
"Let's take nitrogen for example. It's a very important element because we find it everywhere. It's in the air, in the Earth's crust, in plants...any other examples?"
"It's used to make bombs right?"
"What about DNA?"
"DNA... " Namjoon repeats the last word. "That's right." He pushes back his glasses. "It plays a huge role in the construction of our DNA as well. Good."
He turns to the board, drawing three very large atoms. "Nitrogen is pretty easy to remember. Why is that? It has 7 proton and 7 neutrons. Thus it's atomic number... Is 7."
He turns back to the class, eyes sparkling with enthusiasm through his glasses. "Simple right?"
All eyes on him, he returns back to the board, drawing another dot and an arrow to the first circle.
"Now what if I add on-?" In the midst of demonstrating he drops the chalk. He chuckles awkwardly, stooping to pick up the chalk cursing his clumsiness. Wow, really Namjoon, you can't even hold a piece of chalk properly.
"Let's say I add one neutron."
Addressing the class, he pushes his glasses back on his nose. "What happens?"
"It becomes an isotope." Songdeuk answers in the front.
"Correct." Namjoon responds at once, writing up the corresponding isotope for nitrogen. "We has seven and now that we have eight neutrons, nitrogen becomes nitrogen-15, an isotope of nitrogen. This doesn't change the electrical charge. Why? Because I added a neutron and neutrons have no charge. They are neutral. "
He turns the second circle. "Now, what if instead of a neutron...I add an electron?"
There is a sharp distinguised silence. He looks a little surprised to see that no one can answer or venture a guess.
"Adding or removing electrons... Creates ions." He continues stirring 'oohs' and 'aahs' and 'i knew thats'. "As nitrogen has 5 electrons on it's outer shell-" He continues drawing up the diagram. -which is the second one, adding one electron would complete it."
The students hurriedly take notes and fixate their eyes back into him watching his every move.
"Finally," He turning to the last sketch, "I add a proton. What does this do?"
"It changes the electrical charge." A student blurts out eagerly.
"Yes. Protons have a positive electrical charge right? But adding a proton, " Namjoon follows, nodding at the student smiling. "Doesn't just change the electrical charge. When you add or remove protons from an atom... It changes the element itself."
A gasp goes around the room and he half chuckles to himself. Here was the reaction he'd wanted to draw out. Beside nitrogen-15 and ion, he writes down 'oxygen.'
"With eight protons we have an atomic number of eight... That is...?"
"Oxygen."
"Right. As you can see, " He concludes, waving a hand in front of his three drawings. "In this case, adding one to seven... Changes everything. That extra one... She can bring change in various ways depending on who she is."
As he gives them their assignment, he wonders back to why he allocated a gender to the component of an atom. He sits down, resting his chin on his jaw rethinking his own words.
The way nitrogen, a gas, was useful for so many things. The way one person made a difference.
He looked out at the students in front of him, picking up their pens and scratching their heads over the exercise he'd given them. He looks at each of them, all so different to him but to them he was the same.
He was Mr. Kim. Their chemistry teacher.
Looking out into the vast sky again, he couldn't help but feel so small with that realization.
He wondered if he could ever be useful in the universe for other reasons.
[I have NEVER done chemistry in my life I had half the mind to go back and change Namjoon's profession.]