"Why isn't it reacting?"
Toma shook the test tube.
Rei asked. "Are the conditions right?"
"Following the recipe."
"What about temperature?"
Toma checked. "Room temperature."
"What temperature does the recipe say?" Rei asked.
"Oh... 60 degrees."
Kana laughed. "The conditions aren't right then."
"I skipped it because it was troublesome," Toma made an excuse.
Rei explained. "Chemical reactions are strict about conditions."
"Especially temperature."
Toma prepared a water bath. "Why is temperature important?"
"Activation energy," Rei answered. "The energy barrier that must be crossed for reaction to occur."
Kana drew in her notebook. "Crossing a mountain?"
"Yes. Higher temperature increases molecular kinetic energy."
"Easier to cross the barrier."
Toma understood. "That's why we heat."
"But too high is also bad," Rei warned.
"Why?"
"Side reactions occur. Reactions other than intended become dominant."
Kana asked. "Is there an optimal temperature?"
"Differs for each reaction. Determined by experiment."
Toma looked at the thermometer. "Reached 60 degrees."
"Wait," Rei stopped. "Let's check other conditions too."
"There's more?"
"pH," Rei handed over test paper.
Toma measured. "About pH 5."
"What's the recipe?"
"pH 7..."
Kana was exasperated. "Different again."
"pH is also important," Rei explained. "Acidity and basicity change molecular charge."
"When charge changes?"
"Reactivity changes. For enzymes, active site shape also changes."
Toma added buffer solution. "Now it's pH 7."
Rei nodded. "Good. What else?"
"More?" Toma became anxious.
"Concentration," Rei pointed out. "If reactant concentration is too low, reaction is slow."
Kana understood. "Probability of molecules meeting?"
"Exactly. Higher concentration increases collision frequency."
Toma checked reagents. "This is as written."
"What about stirring?" Rei asked.
"Haven't done it..."
"Without mixing, concentration becomes locally uneven."
Toma started the magnetic stirrer. "Is this everything?"
Rei thought. "Solvent, impurities, air effects... there's more."
"Too many!" Toma shouted.
Kana comforted. "But they all have reasons, right?"
Rei nodded. "Chemical reactions are the combined result of many factors."
"If even one condition is off, won't proceed."
Toma observed. "Ah, the color's starting to change."
"Because conditions are aligned," Rei confirmed.
Kana asked. "Is it this strict in living bodies too?"
"Even stricter," Rei answered. "Temperature 37 degrees, pH 7.4, precisely controlled."
"What if it deviates?"
"Enzymes denature. Reactions stop."
Toma imagined. "That's why we feel sluggish with fever."
"Deviating from enzymes' optimal temperature."
Kana added. "pH also changes with illness."
"Acidosis, alkalosis. Life-threatening."
Toma became serious. "Condition management is important."
Rei continued. "Industrially, even more complex."
"Pressure, catalysts, reaction time... optimize everything."
Kana asked. "How do you optimize?"
"Repeated experiments. Change conditions, measure yield."
"Recently, machine learning is also used," Rei added.
Toma was surprised. "AI finds conditions?"
"Predicts optimal conditions from large amounts of data."
"But," Rei emphasized, "predictions fail without understanding basics."
Kana summarized. "Conditions = key controlling reactions."
"And the foundation supporting life."
Toma stared at the test tube. "Even such a simple reaction is so complex."
"There's no simple reaction," Rei corrected.
"All reactions occur within a web of conditions."
Kana looked outside. "Weather also depends on conditions, right?"
"Temperature, humidity, pressure..."
Toma laughed. "The world moves by conditions."
Rei smiled. "Science is understanding and controlling those conditions."
Outside the window, clouds drifted. When conditions align, rain falls. Same with reactions.