My health recovery is incredibly fast.

Kulov calculated with his fingers, pondered for a few seconds, and then said:

"That old fellow is as shrewd as ever, finishing teaching the oil preparation method just on the last day before the exam. I'll teach you this book ahead of time."

Xia Zuo heard his mentor complaining about Professor Zhuo Lang, but decided to pretend he didn't hear it and stared blankly at the bottles and jars in the oil tank.

"Have you finished memorizing the mixing of oils?" Kulov continued after seeing the student nod.

"The difficulty in oil science lies in blending oils."

"Professor Zhuo Lang may assign application questions related to blending oils on the exam paper. Students who are not majoring in oil alchemy will probably find it difficult to get full marks on this type of question."

"Hmm, let me think... He wants to make it difficult for students in other subjects to score well, but he also wants to avoid being reprimanded by the head of the department for making the questions too difficult."

Xia Zuo blinked at his pensive mentor and suddenly realized that he had a great advantage!

He was the only student in the Department of Poison Alchemy.

This means that among all the freshmen, he is the only one who can regularly concoct poisons... Well, starting tonight, Anru'er will be there too.

If Kulov's exam included application questions related to making poisons and identifying toxins, he and Anjou would score significantly higher than others.

Of course, the word problems set by Kulov are not very difficult.

The real purpose of setting up word problems is to ensure that students who are meticulous and skilled in alchemy can also achieve high scores, thereby differentiating them from other students.

Each exam should follow a similar question-setting approach.

After pondering for a moment, Kulov clapped his hands and said:

"How about this, we'll start with the past years' oil alchemy exam questions. Professor Zhuo Lang can't set the same questions twice, but you can practice with the previous questions to accumulate experience in blending oils."

He went back into the storage room, took out a large leather suitcase, rummaged through it, and took out two pieces of wood made of different materials.

"The lighter-colored piece is pine, and the darker one is cedar. These are the most common types of timber used for houses."

Kulov pointed to the two wooden planks in turn:

"In the northern part of the kingdom, pine wood is used for wooden houses because the air is drier there and pine wood is more resistant to drying. In the Rosac province, the air is more humid, so cedar wood, which is less prone to mold, is used, and it also has more moisture than pine wood."

Kurov picked up a plank in each hand. "These two types of wood have a common problem: they're not fireproof. We need to use oil alchemy to solve this. Do you have any ideas?"

Xia Zuo subconsciously looked at the fire-retardant oil in the oil tank.

Unlike the edible fire retardant used in fire-breathing performances, the fire retardant in this box cannot be ingested, held in the mouth, or applied to the body.

Kulov followed the student's gaze:

"Fire retardant is too expensive, isn't it? The price of one bottle is equivalent to the timber used to build half a house."

"When answering multiple-choice questions, you can use fire retardant as an option for the question."

"But in word problems, you will lose points because of the high price."

"Applying fire retardant to a small wooden house of ten square meters requires more than a dozen bottles of fire retardant, which is worth more than 20 gold coins in total, making it very uneconomical."

Do you have any other ideas?

Xia Zuo scratched his cheek, racking his brains to recall the knowledge he had learned in his previous life.

Unfortunately, he was not a graduate of chemical engineering or materials science, so the ideas that came to his mind were more like conjecture and speculation.

He hesitated for a few minutes, but ultimately gave up on using scientific methods to deal with the fire prevention problem and turned his attention back to alchemy and oil tanks.

The three elements of combustion are: combustible material, oxidizer, and ignition source or temperature.

This is a basic textbook on forging and casting, covering fundamental knowledge points in the discipline of giant creation.

Wooden houses are inherently flammable, and their interiors and exteriors are filled with air that aids combustion.

Fire retardant itself is non-flammable; it prevents the protected wood from direct contact with air, thus isolating combustibles from oxidizers.

At the same time, its extremely low thermal conductivity greatly slows down the transfer of flame temperature to the protected wood.

According to the complete explanation of fire retardant oils, a large number of raw materials related to the element water are used in the process of refining fire retardant oils.

Xia Zuo nodded to himself, carefully recalling the oils related to the water element, and took out a glass bottle with a long, narrow opening from the box.

Chapter 19 Word Problems Practice (Part 2)

"A good choice."

Kulov glanced at the oil bottle that Shazo had taken out, nodded slightly, and said:

"Foaming oil can generate large amounts of foam by friction and heating it up."

"But it's too sensitive to temperature; even the candle flame on the candlestick will cause it to bubble."

"Moreover, its foam is mostly air with only a tiny bit of water, so it won't significantly weaken the fire."

Xia Zuo realized that his mentor was guiding him.

Following the two points raised by the other party, he briefly considered the matter, put the foam oil back into the box, and took out two other bottles of oil.

The first bottle contains heat-insulating oil.

It can insulate against temperatures below boiling point and is commonly used on the outer shell of teacups and water cups, as well as the handles of soup spoons.

After applying and letting it dry completely, it will become a thin film that adheres tightly to the surface of the object. It will not leave any oily smell, nor will it melt upon contact with water vapor, hand sweat, or other liquids.

The second bottle contains a water-rich oil-based agent.

This type of oil contains many tiny particles encased in air bubbles.

Under external force, the bubbles will burst, and the particles inside the bubbles will come into contact with the liquid in the oil, generating a large amount of water vapor in a short time.

“Your approach is sound. Now try mixing these two oils,” Kurov said, pointing to the alchemy table.

Xia Zuo scratched the back of his head. "Professor, what if I make a mistake?"

Kulov chuckled. "If you make a mistake, you have to clean up the alchemy table. I won't fire you; this isn't like we're making poison."

"That's good."

Xia Zuo shrugged and smiled in response.

He went into the storage room, found a carrying case with grooves, and following the instructions on mixing the oil, inserted the two bottles of oil waiting to be mixed into the grooves to prevent the bottles from tilting during transport and causing the oil inside to spill onto the ground.

Then he went back into the storage room and this time he took out a metal bucket.

Its lid is a piece of transparent glass with a sealing ring.

There is a round hole with a sealing ring in the center of the cap. Insert the matching oil mixer through this hole, and you can safely mix the oil without any odor or leakage.

Xia Zuo repeatedly confirmed that all preparations were in place. He looked at his mentor, who nodded. He then put on his mask, removed the glass lid from the metal bucket, and inserted the anchor stirrer into the round hole.

The tiny air bubbles in water-rich oils are harder to pop than they appear, but they still need to be stirred very gently when mixing the oils.

Anchor mixers perfectly meet this requirement.

Its blades are close to the lower side of the inner wall of the metal barrel, which will drive the liquid to flow from the outside to the inside and from the bottom to the top.

Therefore, the oil that comes into direct contact with the blades must have very good stability.

Xia Zuo poured the most stable heat-insulating oil of the two oils into the bucket, and then slowly poured in the water-rich oil using a glass rod to guide the flow.

Two distinctly different pungent smells wafted from the barrel.

He suppressed the urge to sneeze, quickly and steadily closed the glass lid, and gently turned the handle of the stirrer.

The two-colored liquids in the metal bucket gradually merged.

Whenever the blade is about to cut through the bubbles of the water-rich oil, he turns the handle with a gentler force.

Five minutes later.

The two oils were completely mixed together. The two-color liquids blended into an amber color.

The next step is to use a soft brush to apply the freshly mixed oil to the wooden board.

Or

"Professor, may I soak the wood blocks in this bucket of oil?"

Xia Zuo walked to the table and bent down to examine the wooden blocks. "We need to take them out to dry in the sun first, so that the wood can absorb the oil better."

"The method you mentioned is called the impregnation method, which is an introductory level of oil alchemy."

Kulov pointed in the direction of the storage room, "Now that we're in the apprentice level of instruction, let's use a brush to apply it."

"Okay, Professor."

Xia Zuo went into the storage room and selected a brush made of short wool.

Wool brushes have the softest bristles, making them especially suitable for handling delicate objects. Most makeup brushes are made of wool.

Xia Zuo laid a layer of oil-repellent cloth on the alchemy table, then placed a special stand for applying oil on it, put two wooden boards on the stand, and gently applied the oil with a wool brush.

After coating the front, back, and sides of the wooden block, use tweezers to pick it up and put it into an oven to dry.

A dozen minutes later, Xia Zuo, who had been busy for most of the hour, finally completed the practical training.

"Professor, shall we test the fire resistance of these two pieces of wood?"

Xia Zuo hesitated for a moment and said, "No matter what the results of the experiment are, we will inevitably have to clean up the experimental equipment and site."

"Of course. Go find a deep brazier."

"Ok."

Xia Zuo measured the size of the wood with his arm and found the largest and deepest brazier in the storage room.

He placed the brazier on the stone floor of the alchemy room, used iron tongs to take out red-hot coals and put them in, along with a bundle of dry firewood.

Soon, a flame flickered in the brazier.

He picked up the two pieces of wood that had been processed, hesitated for a moment, and then put them into the brazier.

"Zizzi"

The moisture appeared much faster than expected; almost as soon as the wood touched the flame, thick white water vapor billowed out.

A sour, foul odor filled the alchemy chamber.

Xia Zuo covered his eyes and nose, coughed a few times, and said, "Cough cough, Professor, does this count as a success?"