The audience was silent, everyone looked at Li Zhen in amazement, and then looked at Qi Dengming, who was red-faced and thick-necked.

This...... It's amazing.

This phenomenon of hot ice is inherently magical. I didn't expect Li Zhen to be able to say it in one sentence, what else did he not know?

Li Zhen continued: "The so-called hot ice phenomenon is not actually ice. It is a supersaturated sodium acetate solution, and after some stimulation, too much solute will start from top to bottom, forming diamond-shaped crystals. It looks like ice, but in fact, the crystals emit heat, so it is called hot ice.

A supersaturated sodium acetate solution looks like water, but it's not water. Its interior is in a metastable state. If the solution is contaminated with sodium acetate trihydrate crystals, this equilibrium will be broken, and the solute will be stimulated to crystallize rapidly. When sodium acetate crystals are added to the supersaturated solution, the crystals will become 'seed crystals' and thus become a medium, guiding the process of breaking the supersaturation equilibrium and reducing all to crystallization. This is not a water-to-ice test, but a test to reduce a supersaturated solution of sodium acetate to sodium acetate crystals. ”

Qi Dengming was already stunned at this time, unable to say a word, and the pestle was extremely embarrassed there.

At this time, a chemistry teacher asked: "Li Zhen, I don't agree with your statement." Sodium acetate is widely used, so we have a lot of experiments with sodium acetate. You say it's a solution of sodium acetate, but we used to mix sodium acetate crystals with water, so why didn't they crystallize at that time? ”

Li Zhen smiled: "Teacher, if sodium acetate and water are mixed together to be a supersaturated solution, then this is too simple. ”

The teacher asked rhetorically, "Then why did you say we didn't find out before?" Why is it crystallizing now? ”

Li Zhen said: "Because I want to crystallize sodium acetate, there are still some processes. The first step is to mix sodium acetate with water to 1.3; 1 state, sodium acetate soluble in water. The solution is then heated to a boiling state, about 80-95 degrees. Stir continuously during the heating process until the sodium acetate crystals are completely fused with the water. Until the surface of the heated sodium acetate solution forms a thin film, and then it is placed to cool, it can be called sodium acetate supersaturated solution. ”

Everyone turned their heads to look at Qi Dengming and asked:

"Is that so?"

"Do you really want to heat it up?"

"Heat and stir?"

“……”

Qi Dengming smiled bitterly, hugged his fists and bowed to Li Zhen: "Master Li!" ”

'Wow-'

There was an uproar, it was true.

Qi Dengming said: "Yes, when I was doing the experiment, I had a whim, what would happen if the sodium acetate solution was boiled. Then I heat the solution and boil it. I cooled the boiling solution and wanted to move it somewhere else. But my hand shook a little, and the solution accidentally spilled onto the sodium acetate crystals on the table, and the water that spilled out at that time, oh no, a supersaturated solution. It froze on the table on the spot...... It was by accident that I discovered such a phenomenon.

I originally wanted to challenge Master Li's knowledge with such a phenomenon, and by the way, I also wanted to attract everyone's attention and announce such a phenomenon. But I didn't think of it...... Master Li has insight into everything, and I don't understand why I stumbled upon the phenomenon, but he can explain it in one word. Admire. ”

As he spoke, Qi Dengming bowed to Li Zhen again.

Everyone couldn't help but get goosebumps and sighed.

Science, what is science?

Isn't it just the result of trial and error?

Qi Dengming is representative, whimsical and accidental.

Occasionally, the hand trembled, and the solution was spilled, and by accident it spilled onto the table where the crystals were sticky, and by accident the phenomenon of hot ice was achieved.

Science is an accident that constantly appears in the process of trial and error.

Li Zhen also bowed to Qi Dengming: "Senior Qi can discover that this phenomenon is the favor of God, and we should respect everyone who has science in their hearts." I also admire Senior Qi's bold assumptions and trial and error spirit. ”

Qi Dengming smiled bitterly, full of emotion, and didn't know what to say for a while.

In the silence of the scene, Xu Shenxue suddenly spoke: "Li Zhen." You just said that there are other ways to freeze water? Or is it real ice? ”

As soon as these words came out, the scene became even quieter. Everyone turned their heads to look at Li Zhen again, their eyes full of anticipation.

Li Zhen nodded: "Yes." There are also many ways to freeze water. ”

Xu Shenxue walked over and said excitedly: "Tell me about it." ”

Li Zhen never hid anything from other people's questions, and said bluntly: "There are also ammonium nitrate freezing, calcium nitrate, and ammonium chloride freezing. ”

"There are so many ways to freeze?"

"Is this true?"

"What is ammonium nitrate?"

"Water doesn't have to wait until winter to freeze, it turns out that artificial can also freeze?"

"That person is too rebellious, this is a rebellious move."

“……”

Li Zhen said indifferently: "If you want to freeze water, then you need to know the characteristics of water. Water at a pressure of 1 atmosphere, below 0 degrees, will reach the freezing point. In the freezing water, one molecule produces crystals, which can be called 'seed crystals', which then become a medium and rapidly infect other water molecules of the same temperature. As a result, large areas of ice are formed. This is one of the three forms of water: steam, water, and ice, and the properties of ice. ”

A chemistry teacher stood up and trembled with excitement: "And then? And then how to freeze? ”

"Take ammonium nitrate, for example. The characteristics of ammonium nitrate are: water absorption, agglomeration, and heat absorption. While the water is turned into ice, we take ammonium nitrate for endothermic properties. Can be used in a large basin...... In this way, Is there any ammonium nitrate in the lab? I experimented with it in the field. ”

"What is ammonium nitrate?"

A chemistry teacher asked weakly.

Li Zhen slapped his forehead, and forgot about it. Fuxing University does not yet have the capacity to produce ammonium nitrate. Without him, ammonia gas is in the main structure of ammonium nitrate, and ammonia needs to be prepared under high pressure and high heat, and Fuxing University does not have the equipment to reach high pressure for the time being. After that, there was no technology to extract ammonia because it was highly toxic and difficult to extract.

"In that case, we will replace ammonium nitrate with saltpeter. At a certain temperature, saltpeter can also have a chance to freeze water. ”

After listening to what Li Zhen said, Xu Shenxue hurriedly jumped to his feet: "Quick, find saltpeter!" ”

"Saltpeter."

"Hurry up, go get saltpeter."

“……”

One by one, the classmates who stood behind and watched the excitement ran out and looked for saltpeter everywhere. The enthusiasm for science is extremely high.

Within ten minutes, someone picked up what Li Zhen wanted to use.

A large basin, a bag of saltpeter, a beaker.

Li Zhen first filled the large basin with water, then poured all the saltpeter into the basin, and handed a wooden stick to Qi Dengming: "Stirring water and saltpeter will fully absorb the heat in the water." ”

Qi Dengming was shocked: "This ...... Is it that if you stir it like this, this basin will freeze? ”

Li Zhen smiled: "Naturally not." ”

Turning to look at his classmates, he said, "I need a glass of water from a deep well." Nowadays, the outdoor water at room temperature is high depending on the weather, and it takes a long time to achieve the effect. The water in the deep well has more heat loss and lower water temperature, which is more suitable for the rapid completion of this test. ”

"Go, fetch water from the well!"

"I want the iciest well water!"

“……”

Some students ran to the edge of the well in groups on the spot.

"The coldest well water?"

"In fact, the closer you get to the bottom of the well, the icier the water is. The water temperature on the surface of this well is still relatively high due to the weather. ”

"So you hang me down, and I will go to the bottom of the well to get water from the deep well."

"Stay safe,"

A classmate took off his bare shoulders on the spot, tied a rope around his waist, and slowly climbed down with a bottle with a cap in his hand.

'Puff' jumped into the small well and dived in. Go to the bottom of the deepest well.

The surroundings were full of classmates, talking about Li Zhen.

After waiting for about two minutes, there was no movement in the well, and some students used flashlights to shine down, but it was quiet.

"Classmates!"

"Quick, pull it out!"

"Pull him out."

"The well is so deep that it has drowned. Don't be surprised. ：”

"Oh no, the rope is broken!"

"Ahh Shout for help. ”

"What to do, what to do?"

“……”

Just as everyone was in an uproar, there was a 'poof' sound, and there was movement in the well.

Everyone hurriedly leaned over and looked inside, but saw that the shirtless classmate was covered with water droplets and kept panting for breath. Seeing that everyone at the wellhead looked at him with concern, he smirked, and proudly raised the bottle with the cap tightened in his hand:

"I got it, it's cold!"

"Pull me up and get the cold water over quickly, or the cold water will be ruined by room temperature." I'm going to see the experiment. ”

“……”

Everyone looked at the classmates who smirked and climbed up at the bottom of the well, silent.