The Good Teacher

"What in the world are you doing?" Yohn asked while approaching Revian slowly.

The boy in question was intensely focused on the beaker, trying to absorb all the volatile mana escaping from it back into his mana channels.

"The secret..." Revian grunted, "...is in the volatile mana- Ah! Damn it, it escaped!"

"You have to explain what you're attempting here," Yohn said with a confused tone as Revian poured out the water in the beaker and refilled it from the large bottle beside the table.

"The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time. So with any thermal interaction, the total entropy is always increasing. It is because of this that hot coffee in a cold room doesn't get hotter," Revian stated. "To do that, you need to transfer heat to this coffee through another process. This is true with any physical interaction in the True World. But what about a world with mana? How does mana and magic play a role in this."

Noticing Yohn's blank expression, Revian continued, "You can heat a coffee with a spell. You can enchant a cup to maintain the heat of whatever is poured inside it. This action in and of itself, should the second law hold true, will cause the total entropy to increase. But does it, though? There is no heat transfer happening here as we are, quite literally, just creating heat out of nothing."

"It's not out of nothing, you're using mana," Yohn corrected.

"But have you noticed the release of volatile mana differs based on the nature of the spell used?" Revian proposed. "I took some time to categorise the types of spells that are common and usable by every mage. You have the abjuration school which consists of protective spells, conjuration school which involves translocation of things from one location to another or even creating something out of nothing, there is the illusion school which works to influence the mind of others, there is the alteration school that changes the property of something into something else, and there is the evocation school that use mana to produce a desired effect. Using water to create a bubble of protection is abjuration, creating water or moving water from one source to another location is conjuration, making something think that they are drowning when they aren't is an illusion, turning water into oil is alteration, and heating water in a beaker is evocation. I have noticed that spells classified under the school of evocation always release volatile mana."

"Did you come up with this classification by yourself?" Yohn asked in surprise.

"Not technically. It was kind of already out there, I just standardised the naming conventions," Revian dismissed. "I'm going to write a short report in hopes of spreading this standardised classification though."

"Anyways, as I was saying, evocation spells always call for energy manipulation or generation," Revian expounded. "Now, I know this may fall under the classic correlation-causation fallacy, but I believe that volatile mana is generated when mana interacts with energy."

Revian halted Yohn from raising a point and said, "This theory is corroborated by the fact that moving pure carbon from one location to another by means of teleportation is more expensive and releases volatile mana, but creating the same amount of carbon through direct transmutation of mana."

"How does that make sense?"

"You just added or removed mechanical potential energy to the carbon by teleporting it," Revian emphasised.

"I still think it's a weak connection," Yohn said with an unsure intonation.

"Which is why we are doing this experiment. I believe that the proof can be found in the released volatile mana," Revian reiterated.

"Proof of what?"

"Whether the second law of thermodynamics holds true regardless of whether magic is in play or not. Basically, as I use mana to reduce the temperature of this beaker of fluid, the by-product volatile mana should carry the 'heat' extracted inside it," Revian said.

Yohn scratched his chin and asked, "How do you intend to do that?"

"I don't know," Revian admitted. "I haven't found any literature in which a mage has recaptured the volatile mana and examined it. After realising that it is unusable, people just dismissed it. So the greater half of this experiment is to discern the properties of the volatile mana. And to do that, I need to reabsorb it into my mana channels."

"Is it dangerous?" Yohn probed.

"If it were, I don't think Senior Brother Markus would have approved this experiment. He was sceptical, though," Revian clarified.

"Well... carry on, then," Yohn said finally before returning to his spot to oversee the experiment.

Revian cleared his throat, announced the start of the trial and once again proceeded to cool the 100ml of water to 20 degrees. Once the desired temperature was reached, Revian covered the beaker's top and started to absorb the volatile mana with utmost focus.

After the mana was completely recaptured, Revian ended the spell and started to meditate while circulating the volatile mana through his mana channels. It was an uncomfortable process, but not painful. The volatile mana threatened to disperse out of his channels the moment he moved his attention away from it. After five unfruitful minutes of moving the mana around, Revian decided to try something stupid and took it straight towards his nascent core. However, the mana just refused to enter his mana core. So, Revian started to circulate the volatile mana around his channels with increased velocity and sent it hurtling directly into his core.

The mana pierced through his core immediately, causing a pang of pain to echo out from his lower abdomen. Just as Revian collapsed in pain, he was caught by Yohn.

"What did you do? Your entire body temperature just shot up by a few degrees Celsius for a fraction of a fraction a second before you collapsed," Yohn exclaimed while grabbing Revian by his shoulders.

"My... what did you say?" Revain said between heavy breaths. Yohn repeated his observation, and a maddened glint flashed past Revian's eyes.

"I'm going to do it again," Revian declared while pushing Yohn away. "Stand prepared."

"There was no indication of you crumpling in sudden pain in the safety documentation, Revian," Yohn warned. "You're going rogue!"

"I'm at the cusp of something new here, can't you see?" Revian argued. "Just... Just keep observing!"

"Proceeding to freeze 100ml of water," Revian declared without waiting for Yohn to consent. As stated, Revian let the spell work till crystals of ice started to form at the side of the beaker. Revian then immediately absorbed all the volatile mana and started to meditate. He didn't hesitate to send the hurtling injection of volatile mana into his core. This time, he braced for impact and when the pain echoed from his core, he bit through it and noticed the changes happening in his body. The moment the mana pierced his core, a wave of heat carried by raw mana started to pulse outwards. Revian immediately took control of this raw mana and instead of letting it wreak havoc across his body, he channelled it through his mana channels.

The pain that was assaulting him then suddenly became concentrated on the mana pathways through which this raw mana moved. Unable to handle the pain any longer, he quickly expelled the mana out of the exits on his free palm.

As he caught his breath after that ordeal, Revian noticed Yohn approaching him with a scrunched-up face.

"Did you see something?"

"I saw something, alright!" Yohn answered cryptically. "I don't know what I saw, but I'm sure it was something."

"Stop talking in riddles and just say it," Revian said irritatedly.

"Well, your core suddenly became extremely hot and started to spread outwards. But then it seems you did something and took control of this... heat and channelled it all over your body. Wherever it went, I saw a temperature rise. The moment it left through your palm, the air in the vicinity just shot up in temperature by around ten degrees Celsius before dissipating," Yohn narrated. "So what DID I see?"

"It seems that a mage's mana core has the ability to deconstruct the volatile mana and turn it back into raw mana. Makes sense, because wisps and slimes are known to be able to cleanse an environment of volatile mana as well- How did I miss that?!" Revian exclaimed while slapping his forehead. "In the process, though, it reverses the action the mana was originally used to do. Basically, since I used a spell to reduce the kinetic energy of water particles in the beaker, the reverted raw mana carried all that extracted energy with it. So I was right! Entropy DOES increase- the second law of thermodynamics is still valid!"

Revian leapt up and clapped his feet together in excitement.

"Is that it, then?" Yohn interjected.

"What do you mean, 'is that it?'! This is a huge discovery-"

"I meant does this mean your experiment is complete?" Yohn clarified before Revian could descend into a long tirade.

"Of course not! This is just the beginning. We have so many more thermal interactions left to explore. After that, we will try testing out some other evocation spells that release volatile mana and investigate that. Finally, we'll spend some time trying to see if there is any practical use to all this," Revian listed out enthusiastically.

"Woah! Slow down there," Yohn blurted out. "I get that you're excited. But I really feel like we're toeing the line on safety here. We should at least get you checked out to see if there's anything wrong with you."

Revian waved his hand dismissively and said, "I'm perfectly fine. You saw that nothing changed in my body. It's just a momentary thing, is all!"

Yohn nodded apprehensively, though a foreboding sense started to gnaw at the back of his mind. Sometimes, the cracks are hidden so deeply, that it is hard for even the most observant person and accurate sensors to see.