"According to the principle of thermal expansion and contraction, when air is heated, its volume expands and its density decreases; when it is cooled, its volume shrinks and its density increases."
"When the air density decreases, it rises to form a low-pressure area, and when the density increases, it forms a high-pressure area. Due to the pressure difference, the air in the high-pressure area moves to the low-pressure area, which can create natural wind."
Misaka sat on the grass in the playground, still looking a little depressed. While secretly glancing at Shirai-san, who was pulling weeds seriously, she patiently taught Natsume, who had just entered the first grade of junior high school, some simple knowledge.
"Oh, I see."
Natsume looked serious and listened attentively to Misaka's teachings.
Although she didn't take any notes, Natsume thought this knowledge was not difficult at all, even for someone who had just entered junior high school.
Thermal expansion and contraction, or air circulation, were concepts Natsume had known about for a long time, but she had never thought about using them in the development of her ability. Her main focus had been on her old profession of controlling temperature. Controlling the atmosphere seemed more like the development direction for aerodynamics.
After all, you have to learn to walk before you can run, right? Natsume secretly excused herself.
Misaka was worthy of being able to develop a super-electromagnetic gun with her fragile palms. Not only was her computing power extraordinary, but she was also quite knowledgeable.
As for the development of her own temperature control ability, Natsume had made some assumptions, but she had not thought about it in depth.
Natsume-san briefly recalled some of the principles and knowledge mentioned by Misaka, and her brain began to speed up. Sparks of computing power splashed in the girl's head, and Natsume's ability was fully unlocked.
After a while, the previously normal temperature around her suddenly became abnormal.
Extreme cold and extreme heat alternated. The air around her began to flow in a regular pattern.
Seeing the strong wind formed by the pressure difference blow away the sweat on Shirai-san's face not far away, and with no major mistakes, Natsume immediately smiled.
Can she work part-time as an aerodynamicist now?
It seemed that many level 5s could work part-time, and Natsume had this talent!!
Thinking of this, Natsume, who was thinking divergently, immediately applied her special skill of learning from one example and using it to other situations.
Natsume's palms alternated between high and low temperatures as she used her ability to change the air pressure around her hands. The difficulty was similar to that of making Ice Gekota not long ago.
Not long after, a micro-cyclone gradually formed on Natsume's hand. After a little relaxation, the cyclone dissipated, and a micro-air wave immediately appeared, overflowing in all directions.
After trying several times, a small cyclone finally appeared steadily on Natsume's hand.
Natsume blinked as if she was full of curiosity about discovering a new toy.
"Compared to pure temperature control, the consumption of affecting air pressure through temperature changes is much smaller. As long as the temperature is maintained for a short period, the pressure difference can achieve a wonderful effect," Natsume thought to herself with a happy face.
"Wind, listen to my call!"
Based on the temperature range she could control at this stage, as long as her calculation speed was fast enough, she could form a small whirlwind by constantly changing the air pressure nearby.
Under this premise, Natsume Enako could, of course, freely control the direction of the whirlwind.
However, if she wanted to form a large-scale whirlwind or even a tornado, even though the general operation required was not fundamentally different from forming a cyclone in her hand, the required computing power would be thousands of times greater, which could burn Natsume's brain in an instant.
"Natsume-san is smart," Misaka suddenly felt a little emotional. She had just made a slight suggestion, but she didn't expect Natsume-san to be so quick-witted and able to draw inferences so rapidly.
"No, actually I didn't control it very well; I just tried changing the temperature several times in a row." Being praised by Misaka, Natsume immediately showed an embarrassed smile on her face.
Speaking of which, Misaka is nice.
She casually mentioned that she was a little worried about the regular test next week, hoping to be promoted to a level 4 Great Ability user recognized by Academy City. Misaka gave her advice seriously.
"Sister, Natsume-san's calculation ability must be level 4, as long as it meets the test requirements." Shirai stopped what she was doing and placed the weeds she had gathered onto the pile of grass that had already accumulated into a small hill.
Shirai-san subconsciously rubbed her aching shoulders before walking toward her sister and the others not far away.
"Comprehensive and regular testing, which we often call physical testing, is an inspection activity that systematizes abilities and makes simple judgments based on established standards."
"Each school will evaluate the accuracy, intensity, speed, distance, and duration of a student's ability release. As the level increases, the scope of application becomes wider, so the evaluation criteria also become more complex and multifaceted," Shirai explained slowly, smoothing her skirt casually, her eyes falling on the empty seat next to Misaka.
Seeing that Misaka made no move to refuse, Shirai Kuroko sat down happily. A genuine smile appeared on her face, which was rare, and it wasn't a strange smile but one that was rather sincere as she sat next to Misaka.
Natsume didn't think that Shirai-san had changed her temper, but rather that she might have changed her strategy. She couldn't help but think with some suspicion.
"Different abilities have different evaluation methods, but as far as I know, all abilities are generally divided into two categories. The first category is extrasensory perception, and the second is telekinesis. Among them, extrasensory perception has many different sections in the physical examination, while telekinesis is only divided into one section."
Shirai stretched out a finger, and seeing that Misaka was also listening attentively, a smug smile appeared at the corner of the girl's mouth.
"For example, my spatial movement, Natsume-san's temperature control, and my sister's electric shock all belong to the category of telekinesis. Although they are all in the same category, the emphasis on the detection method differs."
"As for my spatial movement, it is evaluated based on three elements: the size (mass) of the object being moved, the distance, and the accuracy."
"If Natsume-san wants to advance to level 4, the easiest way is to work on several evaluation factors of temperature control, such as the limit value of temperature change, the range of change, and the accuracy of the change. As for the idea proposed by my sister, it can only be regarded as an application of ability at most, and cannot be calculated into the results of the physical examination."
Shirai-san touched her chin and thought for a moment before carefully helping Natsume-san analyze the information.
Misaka's face flushed slightly, and she hugged her knees with both hands, smiling awkwardly.
"But if the air pressure difference can be developed into a super-electromagnetic gun similar to my sister's, then maybe the school will create a special evaluation standard for Natsume-san. As far as I know, every level 5 super ability user has a dedicated research team," Shirai-san added.
"By the way, what kind of old-fashioned term is 'comprehensive and regular checkup'? The habits of elementary school should be left behind, Natsume-san," Shirai said, holding her forehead as if she rarely heard such outdated terms.
Natsume Enako's face turned slightly red. This was indeed a habit she brought from elementary school, although there was no real difference between the two.
The sun gradually descended from its zenith, and time passed by little by little.
The hot weather did not dampen their enthusiasm for the task at hand.
In the playground, three figures bent over to clean up the weeds. The students of Tokiwadai Middle School who passed by curiously glanced at the three hard-working figures.
It wasn't clear when, but Misaka and Natsume had both joined the weeding team, and their relationship had grown closer without them even noticing.
Senior Misaka bent over to weed, while Shirai-san worked even harder beside her. Natsume was at the end of the line, looking a little out of breath, though she was only responsible for putting the weeds into the garbage bag.
"It's finally over."
After picking up the last few weeds in her sight with trembling hands, Natsume couldn't help but sit down on the playground, nearly collapsing from exhaustion.
Misaka was in much better condition, so she ran to the school vending machine to buy three bottles of drinks. Shirai-san immediately grabbed one happily.
"Strawberry soda?" Natsume picked up the drink bought by Misaka and realized it was a rare strawberry-flavored soda.
"Sister, Natsume-san, I still have a patrol mission for the discipline committee. I'm leaving first," Shirai gulped down a bottle of soda, looked at Misaka reluctantly, and then spoke.
As soon as the words were spoken, Shirai-san disappeared without a trace. Her space movement ability was truly enviable.
"That girl is busy." Misaka took a sip of her drink, lay down on the grass, and muttered.
"Natsume-san, I've always wanted to ask you something. Don't you have to participate in club activities?" Misaka turned around and looked curiously at Natsume, who was also resting comfortably on the grass.
"Don't worry, Misaka-senpai. I'm in the Urban Legend Investigation Club. There's no actual activity room, so lying here can be considered investigating urban legends," Natsume opened one eye and glanced at Misaka, wondering what was going through her mind.
[When the wind turbine blades rotate in the opposite direction, something strange happens on the street.] The main subject of this urban legend, Misaka, instantly showed a surprised look, as if lamenting that such a club exists at Tokiwadai Middle School, where its members are allowed to simply relax.
"That's a special club," Misaka said with a hint of admiration.
"It is special," Natsume nodded seriously, approving of the club's uniqueness.