Now that people's living standards have improved, they are willing to enjoy the products they make, and they also have the means to do so.

He broke the saltpeter into pieces and put them in a large wooden barrel, and then found a small wooden barrel made of thin sheet metal.

Both buckets were filled with clean water. A lot of saltpeter was placed in the large wooden bucket. Then the small wooden bucket was covered and placed inside the large wooden bucket filled with saltpeter.

As the water in the large wooden barrel was stirred, the heat drawn away by the saltpeter caused the temperature to slowly drop to around zero degrees Celsius, at which point it began to freeze into ice.

Saltpeter can absorb heat, especially in water. When the heat drops to a certain level, it will naturally freeze.

The water in the small iron bucket, without the addition of saltpeter, would normally not freeze.

It is also impossible for the temperature to be drawn away.

But now, because the small iron bucket was placed inside the large bucket, all the water in the large bucket had frozen, which also froze the small iron bucket.

The water in the small iron bucket gradually turned cold, then slowly turned into ice crystals, and finally solidified into ice blocks.

This is called freezing with saltpeter and then making ice from ice.

After completing this step, Zhu Yunwen took a sharp knife and cut the ice cubes in the small iron bucket into pieces.

Then it was presented to Zhao Qingzhu.

Zhao Qingzhu was fanning herself, a little sweat on her forehead, feeling so hot she didn't know what to do.

Then he saw Zhu Yunwen holding a block of ice and handing it to him. The moment Zhao Qingzhu saw the ice, he was completely stunned and couldn't believe it.

After all, ice is something that is very common in winter, but it seems impossible to see it in summer.

However, it actually appeared right in front of her.

Zhao Qingzhu then looked at Zhu Yunwen in surprise and said:

"Where did this come from?"

Zhu Yunwen said:

I made it myself.

Zhao Qingzhu had no doubt about Zhu Yunwen's words and immediately took the ice, saying:

"You're amazing..."