There are many videos of compressed objects on the Internet, and it seems that everything can be compressed, but I have never seen compressed water. So can water, as a flowing liquid form, be compressed, and what happens when extreme pressure is applied?
Can water be compressed
Water can appear in the form of transformation, for example, when the temperature is high, it will become a gas, if the temperature is too low, it will become a solid, and at room temperature, it is generally a liquid state.
In conventional wisdom, water can be compressed and broken up after it becomes solid ice. In the form of a liquid, the surface does not appear to be compressible because of the nature of the flow that cannot be bound.
But in fact, everything, including water, can be compressed, but as a liquid, the degree to which water can be compressed will be somewhat different. In addition, because of the characteristics of fluids, it is difficult for the human eye to observe what changes in water after compression from a microscopic perspective.
Theoretically, water is a combination of molecular forms, which are invisible to the naked eye and combine into different shapes, liquid and ice-like as if they were firmly bonded together.
Even in the gaseous state, the water vapor we see is actually an interval formed by the large distance between the molecular structures. The so-called water vapor condenses into water, that is, under the action of temperature, those water molecules slowly converge together from the wide spacing.
When the polymerization reaches a certain level, the gaseous state changes from a liquid state. Similarly, with further polymerization, it will also change from a liquid to a solid.
If we look at it from a microscopic perspective, the three different forms of water are actually the changes in its own space in different environments, in other words, it is like the transformation of its internal space and separation distance after compression.
There is a gap between the water molecules, but this gap is in a microscopic state and can only be observed by humans with the help of instruments. The hydrogen and oxygen atoms, which also make up the water molecule, also have spacing in different active states.
If pressure is applied to them, their respective forms will also change. It's just that the spacing is small, coupled with the mutual force between molecules and atoms, when compressing it, the degree of compression that occurs is not large.
Theoretically, if the temperature does not change, the pressure increases indefinitely, and the water is continuously compressed, and its form will change from a liquid state to a solid state.
The above is only a theoretical state, and it is difficult to present this phenomenon in nature on our planet. In the laboratory, this is possible with the help of equipment and the conditions provided.
Also on other planets, the unimaginable pressure inside it also causes liquid water to appear as a solid. More on that later.
Now, let's take a macro view, in the natural environment of human life, to see what is the maximum pressure faced by water as a liquid.
Actually, this place is the ocean. More than eighty percent of the planet is covered by seawater, and the unfathomable depths of the ocean, the further you go underwater, the denser the sea water is greater than the surface density.
The key reason is that they are compressed by the seawater stacked on top of them.
What happens to water under high pressure
The average depth of the Earth's oceans is around 3,700 meters, and if you look at only some areas, the deepest place is the Mariana Trench, which is more than 11,000 meters deep.
Therefore, the pressure and density of seawater here are much higher than in other ocean areas. Theoretically, every 10 meters of water depth increases by one atmosphere.
According to the formula, the atmospheric pressure of the Mariana Trench is equivalent to 1,100. Suppose a person comes to the bottom of the trench on a diving device and fills a portion of the water from the bottom of the trench.
When the submersible begins to float, the compressed water will gradually decrease and "expand" as the pressure decreases with the change in altitude.
If the container is not strong, and the volume of water expands beyond the capacity of the container, the moment the pressure is released, the container may burst open.
This is not imaginary, as deep-sea explorers have experienced a similar process of pressure release.
In the 20th century, Barton and Bieber became interested in deep-sea anomalies, and they collaborated to invent and modify various deep-sea exploration devices, and then dived to the unfathomable depths of the ocean to explore the unknown.
The original detection device was a metal container, and since there were no windows, even if a person followed the device to the bottom of the sea, they could not see anything. As an engineer, Patton quickly thought of a solution.
If you want to go deeper to the bottom of the sea, the pressure is so high that the diving equipment needs hard glass if you want to leave windows. For this purpose, Barton has been specially designed to use thick quartz glass.
He built a modified diving device, which was a large round ball with an empty interior in which a person could curl up. There are three windows on the surface of the ball to make it easier for divers to view the underwater world.
After the equipment was manufactured, the two men had dived several times in the Bermuda sea, and the depth of the dive was getting deeper and deeper.
The first few dive tests went smoothly and there were no incidents. During a later dive, water seeped into the inside of the metal container. The two of them didn't take it seriously at the time and continued to dive.
By the time all the tests were completed, the huge metal container was pulled up by the winch, and at this point there was a lot of water seeping inside. The staff on the outside need to unscrew the bolts that fix the exit so that two people can get out of the inside.
At the moment when the bolts were loosened one by one, an accident happened, and the water seeping into the inside of the container was sprayed out like a bullet. The huge pressure directly bounced one of the bolts away, and the bolts that flew out smashed a gap in the steel deck.
If the bolt hits someone, it will kill the other person. Obviously, the moment the water pressure under the seabed is released, it will have a powerful effect.
Similar accidents have not happened before. This summer, several foreign tycoons took diving equipment to visit the sinking site of the Titanic, but they unfortunately became funeral objects.
The accident occurred at a depth of 3,800 meters at the bottom of the sea, where the atmospheric pressure is 40 megapascals, which is 390 times higher than on the ground and similar to a 400-kilogram weight.
It is clear that the submersible in which several people were riding did not withstand the enormous pressure, and an explosion occurred inside the submersible under the tremendous pressure.
As you can imagine, human beings are small in the face of tremendous pressure. It is even said that the difficulty of exploring the deep sea is even higher than the difficulty of launching satellites today.
Returning to the problem of water being compressed, the water in the depths of the ocean must have been compressed when it encountered the superposition above. It's just that water is always fluid, which can lead people to think that it is not dangerous.
Interestingly, humans themselves cannot cope with the tremendous pressure of the depths of the ocean, but in the depths of the ocean, there are still various animals alive. What exactly do they rely on to resist strong pressure has always attracted the attention of humans.
And in Barton and Bieber's dive test, there was a test in which they hung a live fish on the outside of a metal container through the turnstiles, just to test whether the fish could survive after diving to a certain depth.
When the metal container was pulled up, it was discovered that the fish was still alive. Obviously, many of the creatures in the ocean can withstand much higher pressures than we can withstand compared to humans.
For water, a substance, not only will it deform under pressure, but its unique existence has also made scientists conduct research around an experiment for more than 20 years.
Water is two types of liquids
The form of water changes with temperature and pressure, such as water vapor, which gradually takes on a liquid state when compressed. But if the temperature gets higher, the liquid will gradually turn into a gas.
If the temperature and pressure increase at the same time, a critical point is theoretically reached, and it is somewhat unclear whether the water is liquid or gas.
In addition to this critical point, there is also a critical point of low temperature for some substances in nature, which is called the second critical point. In the '90s, researchers at Boston University suggested that there should also be a second tipping point for water.
At that time, it was found that as long as the temperature of water drops, its density fluctuates, and the lower the temperature, the greater the fluctuation change.
The researchers theorized that this is the second critical point in which water splits into two liquids of different densities, which are indistinguishable from each other, and that water changes rapidly between solid and liquid states.
However, at that time, it was only a theoretical inference, and there was no condition to carry out relevant experiments. It wasn't until 2017 that researchers were able to capture the morphological changes of water droplets by using more advanced equipment and technology to simulate a vacuum and cryogenic environment.
According to this theory, water is not one liquid but two kinds of water, each with a different structure. Moreover, researchers further deduce that it is precisely because of this characteristic of water that it is an important reason for the emergence of life.
Of course, the above theories are still in the experimental and hypothetical stage, and researchers will still carry out more in-depth research on water than in the next step.
Similarly, other researchers have discovered other forms of water.
Superionized water
The three forms of water are only conventional cognition, and with the deepening of research, 19 related forms of water have been discovered. One of them is related to strong pressure and high temperatures.
In an experiment in 2018, researchers applied a drop of water a pressure of 2 million atmospheres to it, and then used a high temperature of 5,000 degrees Celsius to penetrate it.
Under the tremendous pressure and high temperature, the drop of water did not disappear, but transformed into a strange solid state. This state is called superionized water, and it has a strange black color, and its density is four times denser than that of ordinary ice cubes.
In the experiment, the ice was only 20 nanoseconds long, and there was no such material on Earth. However, scientists believe that the interior of Uranus and Neptune, because of the extraordinary pressure, contains water in the form of superionized water.
And it is precisely because of the existence of this form that the special and disordered magnetic fields of the two planets are constituted. Of course, all this is also speculative research by scientists.
epilogue
Water is an essential element for the formation of life, and from the perspective of the earth, the various states of water are presented around the earth's environment. Conversely, in the depths of the universe, water may exist in other states that we don't know about.
Therefore, this substance, which is closest to us every day and indispensable to us, is actually so strange and mysterious.
Resources:
"Water is not one liquid, but two?!" Global Science June 13, 2018
"What is Implosion? Why Did the Titan Implosion?" The Paper, June 25, 2023
"Superionized Water: A Special Water That May Exist Inside Ice Giants" Popular Science China, October 23, 2023