back to article Boffins prove oil and water CAN mix – if you do it in a gas giant

Oil and water do mix, a group of scientists have discovered. The two substances normally repel one another, but under extreme conditions oil molecules can dissolve in water. A group of physicists from the University of Edinburgh in the UK filled tiny capsules with water and methane gas and subjected them to intense pressures. …

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Can you do this with H2 I wonder

You could light your burps with special fizzy cola. Or drive fuel cells etc.

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Joke

I managed this years ago...

My old Rover 214 had a K series engine which was extremely good at mixing oil and water.

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Unhappy

Re: I managed this years ago...

I had one of those oil mixers, cracking cylinder heads :-)

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Re: I managed this years ago...

"mixing oil and water..."

The same thing happened to the Mrs' rover shortly after I met her, although there was a human factor involved instead of a head gasket. I'd been out to the pub for a 'solids free' sunday lunch, and thought it'd be a good idea to check the levels on her car. Topped up the coolant with Castrol GTX. Shit was I popular. Fortunately, a couple of months later (yep, I was still hearing about it a couple of months later) she topped up the petrol with diesel. She also didn't have the cast iron excuse of being a bit pissed at the time.

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Re: I managed this years ago...

Virtually every well-used outboard motor has this ability. Fishing line cuts the propshaft seal, allowing water to seep in[0]. Mix thoroughly with lower unit gears. Instant milky goo.

[0] Some of the oil leaks out, too, of course, but water is far less viscous. Couple that with the gearcase heating up & forcing expanding air out, then cooling off and thus forming a partial vacuum ... you might say it sucks. Fortunately, it's an easy fix.

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Ionic vs. Covalent Bonds

"the covalent bonds in other polar molecules like salts and sugars"

Sugar molecules have slightly polar covalent bonds. Simple salts don't have covalent bonds at all. Here's a good and very short description of covalent vs. ionic bonds:

http://wps.prenhall.com/esm_brown_chemistry_9/0,4647,170666-,00.html

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Boffin

Re: Ionic vs. Covalent Bonds

Upvote. Let's keep it sciencey.

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Coat

Re: Ionic vs. Covalent Bonds

Just wanted to add that when it comes to chemistry, you're either part of solution or you're part of the precipitate.

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Boffin

Ob Chem

"breaking apart the covalent bonds in other polar molecules like salts and sugars"

Wrong on both counts. Salts are packed arrays of ions such as Sodium (+ve) and Chlorine (-ve). Sugar crystals are bound together by a mixture of weak polar bonds between hydroxyl groups and good ol' Van der Waals forces that make most things stick together to some (weak) degree. VdV forces keep hydrocarbons together when they are liquid or solid. Water, being itself polar, binds to ions and hydroxyls alike, thus liberating them from the need to stick together. Some salts, however, resist even water's charms: silver chloride and lead iodide, for instance.

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Joke

How convoluted

If I want to mix oil and water (or, say a watery substance like vinegar or lemon juice) I don't fiddle with diamonds and hydraulic presses, I just use an emulsifier, like egg yolk.

And like others already pointed out: salts have ionic bonds and dissolving sugars does not involve breaking covalent bonds.

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Boffin

water has a 'dissolved gas' capacity

just to mention, water has a 'dissolved gas' capacity that varies by temperature and pressure. Otherwise fish couldn't breathe, though I suppose algae could still grow since CO2 has a high affinity for water.

The minimum level of dissolved gas in water occurs in the range of about 165F (as I recall). When you boil water, you'll see a point where you get bubbles along the walls of the pot. but temperature is too low for boiling. This is the dissolved gas coming out of solution. Stir it and the bubbles go away as the gas is liberated from the water, and the bubbles don't re-form again. The water has lost the excess dissolved gas.

At the low temperature end, maximum gas capacity is at around 34F.

sorry for using the old Fahrenheit scale. I should've used something more "El Reg", like maybe expressing the temperature in Hiltons, but then I would've become confused or something.

In any case, as you raise pressure, dissolved gas capacity increases.

So yeah, gaseous hydrocarbons will dissolve in water, given a high enough pressure and proper temperature. It may just be that.

/me points out that this is why warm soda/beer goes flat, but cold soda/beer retains its fizz.

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Anonymous Coward

Re: water has a 'dissolved gas' capacity

In "the old days" - if a child in England was ill they were given warmed Tizer*** to drink. A sugary drink with the CO2 bubbles expelled. If you were really ill you had the glucose Lucozade.

*** An orange/lemon fizzy drink.

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Re: water has a 'dissolved gas' capacity

"In the old days", and indeed today, me & mine prefer homemade chicken soup to sugar drinks when we're ill. And here I thought it was us Yanks who were into junk food ...

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Re: water has a 'dissolved gas' capacity

"soda/beer "

Ah, so that's the proper name for Bud?

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Pint

Re: water has a 'dissolved gas' capacity

> "/me points out that this is why warm soda/beer goes flat, but cold soda/beer retains its fizz."

And I'd like to point out that proper beer is served at room temperature and never has any of that gassy crap in it in the first place.

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Re: Lucozade vs chicken soup

Why choose only? When dying of man-flu any and all potential cures should be applied...

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Re: water has a 'dissolved gas' capacity

May I make a couple points?

My homebrewed ales are served at cellar temperature (43F, 6C). That's quite a bit cooler than room temperature around these parts. They have plenty of CO2 dissolved in them, as a residual effect of the fermentation process. Not enough to be called "fizzy", to be sure, but still enough to produce a nice head without force carbonating.

I rather suspect that many a Guinness aficionado (self included) would have a bone to pick with you over calling forced-fizz "crap".

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Re: Lucozade vs chicken soup

Personally, I really hate sugary drinks (including fruit juice, unless properly fermented, of course), so soup or water is it for me when I'm ill. Three cups of coffee in the morning always seem to stay down, though. Being addicted is a bitch.

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Anonymous Coward

Re: water has a 'dissolved gas' capacity

"And here I thought it was us Yanks who were into junk food ..."

It should be pointed out that for most of the 1950s a fizzy drink was a rare luxury for many children in England. The higher price of Lucozade put it into a class of its own. Chickens were another rare luxury until their mass production took off - when people complained they tasted of fish.

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Re: water has a 'dissolved gas' capacity

personally, I prefer a Kebab roll with extra chilli sauce on it washed down with a wee dram or something peaty...

kill or cure... s'always cured me so far...

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Joke

Re: Lucozade vs chicken soup

"Being addicted is a bitch."

Pfft. The worst addiction is the one we all have. Dioxygen. Try going cold turkey on that. It won't end well.

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Clathrates

Methane forms clathrate or 'cage' compounds at highish pressures and low temperatures. Basically, methane is trapped within an ice-like water structure, and the presence of the hydrocarbon stabilises the structure even at temperatures rather above the freezing point of water. Methane migrating upwards from deep in ocean sediments along the geothermal gradient becomes trapped a few metres below the cold seawater present at the seabed (~ 2 deg C)

The effect is to 'stiffen' that layer within the sediment and produce an acoustic reflection horizon, visible on reflection profiles. Back in the 1960s geophysicists were quite puzzled. Took a while to work out what was going on.

You can actually set fire to these ice-like compounds. Looks very odd, burning ice.

So I suppose you could say that methane and water have been known to mix for quite a long time, at least as a solid phase. But clearly, it's a lot more fun with diamonds.

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Anonymous Coward

Applications

“This could have a huge range of applications..." Like killer salad dressing. I smell an Ig Nobel nomination!

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Re: Applications

Killer indeed. You might say positively deadly. Sit down for a nice candle-lit supper with your nearest & dearest, and set off the methane ...

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Mushroom

Re: Applications

" Sit down for a nice candle-lit supper with your nearest & dearest, and set off the methane "

Egg curry for supper again?

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I hope they were aware that this can be achieved at atmospheric pressure too

In 2003 Australian National University chemists discovered that when the dissolved gases were removed from water then oil could be mixed with it.

https://www.newscientist.com/article/dn3408-oil-and-water-do-mix-after-all/

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Paris Hilton

Ocean floor?

It says "findings shed light on how water-repelling substances behave under high pressures, such as those found at the ocean floor" but then the pressure is 20 times that of the Mariana trench.

Which ocean floor are they talking about? Or did I miss the part where boffins are already exploring extra-solar ocean floors?

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Under Pressure

So is this like nitrogen in blood when you scuba dive, at depths the pressurised nitrogen can leave the blood and accumulate in joints (for example), but as you surface the gas expands and does what the layman calls the 'Bends' if you don't give it time to evacuate from the joints and back into the blood (safety stops)..

So in the same principle, when they removed the pressure did the methane separate back from the water molecules, and if so did it really combine in the conventional way of thinking.

Just thinking out loud, if I'm wrong correct me as it's an interesting concept, but they didn't explain what happened when the pressure was released.

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