In the summer, the sun is like fire, the cicadas are noisy, sweating at every turn, the electric fan becomes a hair dryer, and strangers quickly become acquaintances......
The heat of summer has been the same in all dynasties and generations throughout the ages. So how did the ancients who did not have air conditioning escape the heat?
In general, there are people who complain on the spot, write poems and curse the weather, wear thin silk clothes, eat cool food, and stay where it is cool (boating on the lake, enjoying the cool under the trees, hiding in the cave...... There are a few methods, and one of them that we're going to talk about in detail today, is the way to eat cool food.
Many people don't believe it, as early as more than 2,000 years ago, the ancients invented the method of "making ice from hot water".
The words "Xia Zaobing" have appeared in many ancient classics on the mainland, whether it is "Zhuangzi" or "Guan Yinzi", and these two books are from 2000 years ago. So what exactly is the mysterious "summer ice"?
During the Western Han Dynasty, there was an important document involving physics and chemistry, called "Huainan Wanbishu", and its author was Liu An, the king of Huainan (the grandson of Liu Bang).
In this book, there is a method of "making ice from hot water".
"Take the boiling soup and put it in the urn, dense it with new threads, and Shen Zhong will become ice in three days." --- "Huainan Wanbi Technique"
The idea is that some boiling hot water is taken, put it in a pottery, sealed with silk fabric, and then the pot is placed in a deep well with boiling water, and after three days it is possible to get ice cubes.
But is this really possible?
In order to prove the magic tricks of the ancients, modern physicists experimented for a long time and finally cracked this method.
A small amount of water is put into a clay pot, the water is heated to a boil, and soon the cold air in the pot is squeezed out by the water vapor, at this time the mouth of the jar is sealed with a moist cotton cloth, and the body of the jar is quickly immersed in a deep well. The high-temperature clay pot cools instantly, and the most direct result is that the air pressure in the pot decreases.
After the clay pot is taken out, the cotton cloth at the mouth of the pot is opened, and the water inside the pot absorbs heat and expands, and a small amount of ice can be obtained in the pot.
If the above method is modified, more ice can be obtained.
Putting hot water into a cup and then putting the cup into a clay pot is not pouring hot water directly into the pot. At the bottom of the pot is a wooden plank, which plays a very important role - insulation. The cup filled with hot water is then placed into the pot, and the final step is to seal the mouth of the pot. Soon after, the cold air in the clay pot adhered to the clay wall, and according to the principle of liquid pumping and cooling, freezing was doomed.
After experiments, scientists have recognized that the ancients did indeed achieve "summer ice". However, after nearly half a century of scientific demonstration, there is still no consensus in the scientific community on how the ancients realized the summer ice making.
The earlier way to get ice cubes than "hot water ice" was to simply hide the ice.
As early as more than 4,000 years ago, the ancients on the mainland knew how to use the principle of low-temperature ice to hide ice.
According to modern archaeological discoveries, about 4,000 years ago, the people of the ancient Tao Temple who lived in the Shanxi area learned to build the "Lingyin" facility to preserve the ice.
The so-called "Lingyin" facility is actually an ice cave.
At that time, people would take the initiative to collect ice cubes when winter was at its coldest every year, and the reason why they chose to do so was because the ice was the hardest and not easy to melt at this time.
Once collected, the ice is transported to a pre-prepared cave, which is usually built in a shady place and deep underground, so that the ice can slow down the rate of melting.
Of course, ice cubes are not directly put into the cave, but a thick layer of fresh straw or reed mats is spread on the bottom of the cave, and then the ice cubes are put on it.
In addition, for each layer of ice, it is necessary to spread rice bran, leaves and other items in the middle again to insulate and keep warm, so after the layers are filled, the hole is sealed, and then the cave is opened for use in the next summer.
Of course, this method of ice storage cannot completely prevent the ice from melting, but only slows it down, so in order to ensure that there is enough ice to enjoy in the coming year, it is generally stored more when it is stored.
In the following dynasties, this method of ice hiding was basically adopted.
After reading this article, and then look at the popsicle in your hand, will you feel more sweet? You must know that it was so difficult for the ancients to get a piece of ice!