Water is, by far, the most abundant natural resource on Earth, as around 72% of the planet’s surface is covered with it. It’s also the driving factor behind the origins of life, as we do not yet know of a life form that’s not water-based. The same cannot be said for anything else. We know of organisms that don’t require light, oxygen, warmth, or even the Earth’s atmosphere to survive – as many microbes can stay alive in space, too – though every one of them absolutely requires water to function.
While the reasons for all that may be obvious to most – it makes sense that life evolved around the most abundant resource in the environment – it doesn’t have anything to do with the Earth or the environment at all. Water is – in itself – one of the weirdest substances to ever exist, with mysterious properties that aren’t just unheard of on Earth, but anywhere in the universe. Right from its highly-debated structure to the baffling Mpemba effect, it’s exactly these unexplained properties that give water its unique position as the single biggest factor behind all life we know of today, and why finding life based on any other substance anywhere else in the universe is more unlikely than we think.
8. Water’s Inexplicably-High Surface Tension
One of water’s most unique – and mind-boggling – properties is its surface tension. While nothing unusual in itself, as every liquid has some surface pull that keeps its molecules together in that state, water’s surface tension is much higher than any other liquid we know of. This unique property has some far-reaching consequences for the evolution of life on Earth. For an example, it’s how blood – over 80% of which is made up of water – can overcome the force of gravity and circulate around the body.
As for why this is, you guessed it: we’re not sure. Scientists previously believed that it’s because of the uniquely strong hydrogen bonds found in the water molecules, though if a recent study is to be believed, that’s not the case, and water is actually even weirder than that. Apparently, its surface tension isn’t even static, and could change according to how water is feeling that day.
As the study found, it’s the stickiest just when its surface is formed – like the exact time a water droplet falls down. Surprisingly, it takes unusually long for it to come down to its original value, too, something the researchers didn’t understand. What they did clear up, however, is that it has nothing to do with the hydrogen bonds, or anything else we know of.
7. We Don’t Know Why Water Expands On Cooling, Or Vice Versa
That things expand when they’re heated up and shrink in size on cooling is one of the fundamental rules of nature. We can see it in play all around us, and a lot of our infrastructure takes this rule into account. Almost every building has expansion joints, allowing it to breathe in or out depending on the season. Rules, however, do not apply to water, as it remains the only known substance that expands on cooling and vice versa, and we still don’t know why.
It’s not even difficult to verify this. Just take some ice in a container, note its general volume and wait for it to warm up and liquify. It would always take up less space than its solid form, which also happens to be one of water’s weirdest properties. Science has been trying to answer it for a while, though the potential answers – much like everything else about water – make the whole thing even more mysterious.
According to recent research, there is a perfectly good explanation for this unique property: liquid water doesn’t really expand when it’s cooled, but actually oscillates between two distinct states of liquid matter. If you cool it down below 0 degrees Celsius, it may seem to be expanding, but if you lower it even further, you’d start to notice that it’s contracting, too. Keep taking it closer to its freezing point – which is around -60 Celsius for pure water – and at one point it would seem to be expanding and contracting with almost the same frequency.
While that does seem to explain exactly how and what happens to water when it’s cooled – in the way that it clarifies that the real process is even weirder than we imagined – it still doesn’t touch on the ‘why’. It may have to do with the inherently weird structure of water molecules and how they interact with each other, but then it’s not like we’re sure about how that works, either.
6. No One Can Agree On Its Structure
Most of us would probably not believe it, but water – perhaps the most studied natural material in history – incites some pretty strong opinions in the scientific community, for the simple reason that there’s still a lot of debate around how exactly it’s structured. A lot of its weird properties could be explained if we just knew how the hydrogen and oxygen bonds in water interact with each other. Surprisingly, though, even with our modern research techniques, we still have no idea.
While traditional wisdom previously suggested that despite its weirdness, the structure of water is still a natural tetrahedron, one recent study found that the shape is actually a more loosely bonded collection of closed rings and chains, which is actually what gives water its weird properties. It’s still not a widely accepted opinion yet, though, as other researchers say that the results aren’t due to looser bonding at all, but because of the water molecule’s ability to rearrange itself in entirely new shapes. Whatever may be the case, it’d be a while before we could even understand the structure of water, let alone the plethora of its other mysteries.
5. The Mpemba Effect
While there’s no doubt that water possesses many abilities that may as well be magic to the scientists studying them, a lot of them have been recent realizations. It’s only thanks to recent experiments that we’ve come to understand the full extent of water’s weirdness, as for the majority of history, it was the simplest substance we know of. One of its properties, however, has baffled keen thinkers and amateur scientists alike for centuries – possibly even millenia. Water, contrary to all common logic, freezes at a faster rate when it’s hot. Again, it’s unlike anything else we know of, and has been verifiably observed since at least the ancient Greek times.
Also known as the Mpemba Effect, after an African physics student who wrote the first peer-reviewed paper describing the phenomenon, it’s by far the most enduring of water’s mysteries. Many experiments have confirmed it throughout the years, though we’re still no closer to figuring out why it happens.
4. The Mystery Of The Cambrian Explosion
Our understanding of the evolution of life on Earth is pretty linear; that simple, single-celled organisms gradually gave way to more complex animals, leading up to all the diversity of life we see around us today. However, that is not the case at all. Complex life is a rather recent, and likely accidental, development. For an overwhelming period of our history – about 2.5 billion years – life existed as simple, largely immobile creatures, most of whom didn’t even need oxygen to survive. It may as well have been an alien landscape altogether, filled with animals (if we can even call them that) that have little to no resemblance to the mostly water and oxygen-based life forms of today.
Then about 540 million years ago, the variety and complexity of life suddenly exploded in the oceans, and to this day we have no idea what triggered it. The Cambrian Explosion, as it’s called, was the single most important event in our pre-evolutionary history, as well as the oldest mystery of the oceans. Some researchers think that it was triggered by the rise of oxygen levels in the atmosphere, or the accidental evolution of vision, or something else really. They’re not sure, but almost all of them agree that the importance of the Cambrian Explosion cannot be overstated. It was the beginning of complex life as we know it, and gave way to almost every life form in the world today, from the simplest of microbes to the entirety of human civilization, and everything in between.
3. Where Did All Of Earth’s Water Even Come From?
As we’ve well established by now, there would have been no life on Earth without water. Thanks to its unique and weird properties, water may just be the answer to ‘why us?’, as almost no other substance found in nature behaves like it. Moreover, it’s also rather convenient to have the one substance required to kickstart life to even show up on Earth, completing the unique set of highly-improbable factors that eventually gave birth to life. It begs the question; where did all the water on Earth even come from?
If that sounds like a simple question to answer by something obvious like ‘clouds, duh’ or ‘trees, or something’, it’s really not. As it happens, we still don’t know exactly what brought water to Earth in the first place. Some claim that it came on the back of a comet in the form of ice, though given how the Earth didn’t have an atmosphere around that time, all of that water would have evaporated into the open universe. Another theory says that hot vapors escaping from cracks in the Earth’s surface gave way to the first clouds, setting the cycle of evaporation, cloud formation and rains in motion for the first time. Though again, it’s still just a theory.
2. Water Shouldn’t Even Be A Liquid
If you take a look at water’s placement on the periodic table – provided you know how to read the periodic table – you’d notice something peculiar. It exists right next to gases like hydrogen sulphide and hydrogen selenide, ‘gases’ being the key word. If water were to behave like other chemicals with similar properties, it would not be a liquid at all, especially at Earth temperatures. Water is supposed to freeze somewhere around -100 Celsius and evaporate at around -80 Celsius, as is the case with other gases of its family.
As it’s clear by now, water doesn’t adhere to expectations, which is why it’s the only substance we know of that can exist in all the three states at temperatures hospitable for human life. It can stay liquid at a surprisingly low temperature, too, provided that it’s free of any impurities.
1. The Weird Properties Of Water Make Life On Earth Possible
Reading through the absolutely rebellious chemical nature of water may give you the impression that it’s abnormal. After all, these properties are not found in any natural substance, and we even have a hard time replicating them in the lab if we want to. That’s pretty accurate, though these mysterious properties don’t make water alien. In fact, they explain why water has fit in so well with the life-giving ecosystem of the planet, and is perhaps the most Earthly thing there is.
If water didn’t have a higher surface tension than other liquids, it would be impossible for it to stick to and circulate among plant roots. Its ability to expand when frozen allowed water bodies during ancient ice ages to freeze from top down, allowing life below the surface – which was all life at one point – to survive and adapt for when it was over. If it adhered to laws of liquids, water would start turning into ice from the bottom, ensuring that any signs of primitive life died down long before they could adapt and evolve.