Video Transcript:
I simply wan na speak about ice.
The strange properties of water, thanks to our favorite hydrogen bonds that cause ice to be less thick than liquid water, are crucial to life on Earth.
Ice itself is pretty boring.
Its got some bought hexagons. The solid setup is less thick than the liquid kind, makes our ice tea cold and good and it forms some quite snowflakes, but thats kinda it?
No, incorrect. Ice is remarkable.
Im gon na prove it to you.
Ice is fantastic.
( positive music).
Were speaking about ice.
Is this delivery too strange or is it not odd enough? No one knows.
Not just is ice interesting, however all that things I just pointed out is right here.
It is ice I, however there are likewise all these other sort of ice plus more that cant even be represented here.
We do not even understand how lots of kinds of ice there are. We have actually discovered about 20 up until now, but there might be as lots of as 74,963.
So its someplace in between 20 and 74,963.
Each kind has its own structure and residential or commercial properties and some of them are discovered in diamonds or on Galilean moons. And we are going to discuss all of them. Or like the 20-ish we understand about, I mean not all, 74,963.
Lets begin with the ice that were all quite acquainted with, ice I.
Itll align itself into hexagonal crystal in structures if you take liquid water at normal atmospheric pressures and cool it to absolutely no degrees Celsius.
Because it is a naturally taking place strong with a purchased structure, ice is in fact considered to be a mineral.
Pretty much all ice in the biosphere, which is the part of the Earth where all the living things is, is this type of hexagonal ice one also called ice Ih.
That hexagonal molecular structure is what helps seed the hexagonal structure of snowflakes. However theres likewise a little bit of cubic ice I or ice IC which as the name uses, has a cubic structure.
And this exists at temperature levels in between 130 and 220 Kelvin and might in fact happen method up high in our atmosphere.
Theres also most likely a little bit of stacking disordered ice one up there too, which resembles a metastable ice that exists somewhere between hexagonal and cubic ice. Which likewise assists give snowflakes their threefold proportion.
But what happens if you subject ice to all kinds of pressures and temperature levels to force it into other setups?
That is what this diagram is everything about. This is key to everything were gon na talk about. Lets take a closer look.
What weve got here are phases of ice at different temperature levels and pressures.
The X axis is pressure from low to high and the Y axis is temperature.
Here in orange, we have ice Ih at quite typical ambient temperatures and pressures.
Now you can alter the stages of many products by changing the temperature or pressure that theyre under. And we are incredibly familiar with this?
Changing the temperature level of water can alter the phase its in from a solid to a gas or a liquid. And changing the pressure can have some impact too, but with ice, it does not just stop at strong.
Imagine the hexagonal crystal structure of ice Ih. If you subject that to much, much colder temperatures or much, much greater pressures you can deform and change that molecular structure into all of these other shapes.
So what if we go by doing this on our chart and we take a look at ice at greater pressures. And I need to discuss that these pressures are truly, really greater. We are looking at mega and gigapascals.
A gigapascal is 1 billion pascals.
Your bike tire may be around 500 pascals. So this is 2 million times more pressure than that. Its a lot of pressure.
And if we apply that pressure, we start to move into things like ice III where the hydrogen bonds begin to bend and compress, and then we get to ice V, which has rings with both more and less water particles than our hexagonal ice.
And after that if we keep including pressure, we get to ice VI and we get to ice VII.
Now look, the numbers simply show the order that they were discovered in, nothing about their actual structure. This very first batch of ices I, III, V, VI, and VII are most likely discovered on icy moons in our solar system. Places like Jupiters moon, Ganymede.
On these moons, the layers of ice could be up to a thousand kilometers thick causing substantial quantities of pressure on the bottom layers, forming these other stages of ice.
When ice is compressed like this to offer different stages, it is called a density-driven shift.
And amazingly, that can also occur here in the world. Ice VI and VII have actually been discovered in diamond additions deep in the Earths crust.
You can pull up a diamond and find ice VI and VII trapped inside.
Because of this, they have actually also been designated as minerals. They can be indications of water deep in Earths mantle and its possible that they can contribute to friction in between pieces of earth that could lead to ice quakes. Ice quakes!
Now if we focus on the structure of ice VI, I believe this one is actually, truly cool.
Its actually made up of two sublattices that fit inside one another, however arent connected. There are no hydrogen bonds in between the two so they simply kind of nestle together. Theyre not connected, theyre just hanging out.
Now what if we go the other way on the graph and turn the pressure to unfavorable, basically stretching ice.
Well, what we can really get are types of ice that are less thick than ice I, things like ice XVI and XVII, these are empty clathrate hydrates.
Clathrates are molecular cage structures that often confine another molecule. These are essentially huge empty cage structures.
Normally, these are made in the laboratory by forming the cage structure around another molecule, something like neon and after that vacuum pumping all of those cage particles out.
Now if you let the pressure return to ambient pressure the structures will normally collapse back to ice I unless you keep the temperature really, really low.
What is this? This is no Kelvin, its genuine low.
Now theres something I havent mentioned yet about all of the ices we have actually discussed up until now. They are hydrogen-disordered ices.
This implies that if we focus to the tetrahedral bonds surrounding a water molecule in the ice crystal, the center water particle could be oriented in any instructions. And thats confusing so I made a design, hold on.
( balls screeching).
Hi, this is my art job. And if we believe way back to gen chem or our video on water weirdness, what were discussing here is actually changing the hydrogen dipole or the separation and orientation of the charges on the water particle.
So remember, all we appreciate is the orientation of this center water molecule. If you were to zoom into an ice crystal, it might be oriented like this or if the water particles around it remained in say, this position, we still have these four bonds, but now the dipole is pointing in a different direction.
So prior to it was going by doing this and now it is going in this manner, however there are some phases of ice that are hydrogen-ordered ices. This indicates that there are favored configurations for the hydrogen dipole rather than simply random ones.
And frequently the disordered and ordered ices can be discovered in pairs. So if you cool a lot of the ices that we spoke about down, you can go through an entropy-driven transition Entropy driven transition where moving, once again, down this figure, so lowering the temperature level you can find that their ordered match.
For example, ICE XV is an ordered kind of ice VI right there, ones best below the other.
There is six sets that we understand about today. For each of these sets, youre reducing the temperature level and for that reason youre decreasing the entropy so youre getting more order.
When things like that make sense like that made sense in my brain when I read it, I like.
One of the latest addition to the lineup is ice XIX. Ice XIX was first referred to as a purchased kind of ice VI that utilized to be called ice beta XV. Goes right there.
More recent work has actually revealed that it may be much better described as a distorted variation of ice VI and it might just form at higher pressure. So it might really go a little closer to over here.
There is ice controversy around where some of these limits lie. And I like that controversy means that science is taking place.
However you can even look for structures that dont fit on this graph.
We are discussing some really unusual conditions.
So for instance, if you take ice VII and you compress it to 50 to 300 gigapascals, you can get to ice X.
And ice X is unusual since the water molecules arent even water molecules any longer due to the fact that the hydrogen bonds become balanced in between the oxygen that you can not designate a hydrogen to a single oxygen anymore.
( Alex breathes in deeply).
And if you heat it to over 2,500 Kelvin, it doesnt melt. Instead it develops into ice XVIII, which goes through extremely ionicity where the oxygen remain in a great deal of structure and the hydrogens just sort of walk around them.
Now this hydrogen movement indicates that ice XVIII might be as conductive as some metals and it is possible that ice XVIII is hanging out in the center of hot and truly dense worlds like Uranus and Neptune.
And theres likewise another very ionic form of ice explained in October 2021 that is angling for the title of ice XX.
And appearance, weve been taking a look at the majority of these as like ball and stick models so far, but we can likewise take a look at them as 3D structures like this.
Here you can see that ice Ih and ice II both have whats called these open channel structures. Thats actually obvious there.
While in ice XVI, you can much better see those broadened clathrate cages that I talked about previously.
Here, it is simpler to see how pressure can truly warp the structures to develop things like ice V and VI and VII. They are plainly a lot more thick than ice I.
Additionally, this diagram just reveals these stable forms of ice while there are likewise metastable phases like ice IV and ice XII.
Disordered kinds of ice that just exist in little intermediate conditions, which is why they simply do not have a steady position here on our graph.
However theres likewise amorphous ice.
Amorphous ice doesnt have a long range order to its structure typically due to the fact that it has actually been cooled so quickly that there just wasnt time for a lot of structure to form.
Theres no nice order like any of these that goes on forever. Its just like water particles arbitrarily organized type of like liquid water, which is why its called amorphous ice.
Its actually the dominant type of water in the universe, as far as we know. Nobodys out here measuring each and every single chunk of ice.
Amorphous ice occurs on things like interstellar dust and in places like Saturns rings.
There is a lot of it out there.
Much in fact that it might simply should have a video of its own.
Let us understand.
Do you wan na learn about amorphous ice? I do.
Is that it? Do we just stop at 20-ish phases of ice and stop?
Never.
In fact, a recent computational research study found the potential structures for 74,963 types of ice.
So no, science is refrained from doing with ice structures, but to call a structure to include to that Roman character list, you need to experimentally show the crystal structure.
Therefore in the meantime, were still waiting on ice XXI.
However here, I think, our scientists disagree, so Im also gon na do a take with ice XX.
Therefore for now, were still waiting on ice XX.
Other forms of ice, such as ice III, V, VI, and VII, can be discovered in extreme conditions on icy moons in our solar system, or even trapped in diamonds deep within Earths crust. Ice can be hydrogen-ordered or hydrogen-disordered, depending on the orientation of the water particles within the ice crystal. With more types of ice being found, such as ice XIX and ice XX, our understanding of ice and its different structures is continuously developing.
As brand-new types like ice XIX and ice XX are found, our understanding of ice continues to grow.
Ice XIX was very first described as a bought form of ice VI that used to be called ice beta XV.
Other types of ice, such as ice III, V, VI, and VII, can be discovered in extreme conditions on icy moons in our solar system, or even caught in diamonds deep within Earths crust. With more types of ice being discovered, such as ice XIX and ice XX, our understanding of ice and its various structures is continually developing.
Ice is an intricate substance with at least 20 known forms and perhaps thousands more. Found in different environments, from icy moons to Earths crust, ice can be hydrogen-disordered or hydrogen-ordered. As brand-new kinds like ice XIX and ice XX are found, our understanding of ice continues to grow.
There are somewhere in between 20 and 74,963 kinds of ice due to the fact that water can do all kinds of strange stuff when it freezes. Far, scientists have actually experimentally identified the crystal structures for 19 types of ice.
