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Graphene Aerogel Takes World's Lightest Material Crown
cylonlover writes "Not even a year after it claimed the title of the world's lightest material, aerographite has been knocked off its crown by a new aerogel made from graphene. Created by a research team from China's Zhejiang University in the Department of Polymer Science and Engineering lab headed by Professor Gao Chao, the ultra-light aerogel has a density of just 0.16 mg/cm3, which is lower than that of helium and just twice that of hydrogen."
I'm assuming that the 'density' figure given is a 'weight of graphene in a given volume' one, rather than one that includes the gasses occupying the pores/cells of the material?
It would be quite shocking indeed if something largely saturated in nitrogen and oxygen were less dense than helium...
I still remember the first time I learned about aerogel. The picture had a column of Aerogel about the size of a double-height coke can on one side of a balance and 3 M&Ms on the other side that weighed more.
Make a bag around it. Remove the air. We have an airship with the lift somewhere between H and He.
So how strong is the aerogel? How big a bag can we make and have it support atmospheric pressure on the other side? That will really determine the lift efficiency.
Obviously not 'lightest', but 'least dense'. Sheesh, editors - do your JOB! The /. title should be "Silly folk at Gizmag confuse mass with density when describing world's least dense solid.'
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
" the ultra-light aerogel has a density of just 0.16 mg/cm3, which is lower than that of helium and just twice that of hydrogen."
Picture in the article shows a chunk of the stuff being supported by a blade of grass. If the density's lower than that of helium, why isn't it floating away instead of sitting there like a thing that's denser than the atmosphere around it?
If the substance's density could be altered, it would be possible to have one membrane of gel that was more dense than helium and hydrogen, but less dense than every other element. Then have this gel, which is less dense than helium and more dense than hydrogen. Helium and Hydrogen would flow through the first membrane leaving everything else behind, and then only Hydrogen would pass though the second membrane leaving only helium trapped in between. Given the state of the world's current Helium reserves, this might be a very handy technology.
anti-China bashers go? the ones who keep saying China is a copycat while they weren't born in the70's and 80's when Japan was doing the exact same thing.
Wouldn't the use of the world "Aerogel" sorta indicate that we're talking about a solid?
Or even the term "Material" in context...I mean..using this line of thought you're using, a vaccume is technically lighter, I mean, you didn't specify the lightest 'gas' after all.
And helium. And a lot of other gasses. The aerogel only stays puffed up because it's got air in it. If you're going to be fair you have to count that as part of the density.
Can be used to make the hardest or lightest stuff on the planet.
Carbon's reputation is however spoiled by a couple of Oxygen a-holes that like to latch on to it, stupid no good Oxygen.
I haven't thought of anything clever to put here, but then again most of you haven't either.
Aerogels work just fine in a vacuum and lets you remove the gas filling. Aerogel has been used as dust collectors in satellites and you can find slightly more technical references that will list both the in air density and the evacuated density. If anything, it does worse in air, because aerogel tends to be hydrophilic and doesn't do as well when it absorbs moisture from the air.
Vacuum is a gas in the eyes of Christian fundamentalists. Just like Atheism is a religion, not collecting stamps is a hobby, and off is a TV channel.
I like "off"; there's less re-runs than the other channels.
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This stuff is lighter than helium (presumably at standard pressure and temperature) and yet not buoyant in air. That presumably means it's air-permeable in much the same way that a cellulose sponge is water permeable? In that case, in what sense is it lighter than helium? If you enclosed a volume of this stuff in a gas-tight membrane it would presumably be buoyant in air, but that - it seems to me - would surely be because vacuum is lighter than air?
I'm old enough to remember when discussions on Slashdot were well informed.
Graphene Aerogel Takes World's Lightest Material Crown
A crown should weigh heavy on a ruler's brow, lest he forget the weight of his responsibility.
What makes this so different from, say, creating a hollow cube with some very fine polymer for the vertices, with the faces and interior remaining empty? If something's full of holes, is its density still measurable in a meaningful way? A battleship is less dense than water in this sense, but the material it's made from isn't.
systemd is Roko's Basilisk.
But it will take years to figure out the dynamics of this matrix.
I don't think an elemental gas counts as a "material."
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
Your argument is completely retarded. Helium is also an element and it BEAT helium.
See, that's the problem with mud-slinging - sometimes, a wee bit of that mud comes right back at you.
And the worms ate into his brain.
Here's my stupid question: if it's less dense than helium, and about 1/10 that of nitrogen (1.6 mg/cm3)...why is it pictured *sitting* on anything? Why doesn't it float away?
If, as I suspect, it's porous and it's being measured as 'less dense' than He only because they are taking the actual mass/OUTER VOLUME...well, that's not actual density is it? If so, then by this method my portable dog kennel (made of STEEL) is only an order of magnitude more dense than oxygen.
-Styopa
This thing seems to consist mainly of air. Doesn't that stretch the definition of "material" quite a bit? If I create a 10-foot wireframe cube consisting of just 12 thin aluminium stiffeners, and define the whole interior of the thing as part of the "material", that's gonna have a pretty low density too.
I can change the density of hydrogen or helium by heating it up, or compressing it.
If I wanted hydrogen to be less dense than whatever aerogel, I just need to move the hydrogen to a bigger bottle.
Well, it should be possible to make it less squishy (carbon makes diamonds, after all). Cover it with some other graphene variant in low pressure, and one just might manage to make a lighter-than-air solid. I'd avoid the torch, though.
Aerogel I've worked with was open celled. You put it in a vacuum, the air gets removed (takes a while...), and if you put it back into air, it fills back up with air. And there is nothing at the fundamental level preventing you from making a lighter than air solid, it is just a matter of what is the limits of existing materials. With aerogel at least, there is a trade-off between density and strength (not linear though). There are aerogels that you could evacuate, put a thin sealed sheet over, and would not collapse from atmospheric pressure. Those are not lighter than air when evacuated though. And even if one is found such that it could be used as such, it might not be economical if it turns out you need many cubic meters just to lift a kilogram.
Pedant.
This is why no one under the age of 32 today has any fundamental understanding of the English language. ... This is why they put their punctuation inside of quotation marks even when the punctuation is not part of the thing being quoted...
Funny, APA, MLA, and the Chicago Manual of Style all recommend putting the period inside the quotation at the end of the sentence even if the original quotation does not have a period. And my copy of the Chicago Manual of Style is older than 32 years. Not that I put much effort into writing random forum posts and I'm sure I make plenty of mistakes. But if one were to try to argue technically about what is the correct approach, at best you can argue it is a stylistic choice. Otherwise, you are going against what are essentially the authorities in many circles of writing.
"Which explains why osmium is more dense than lead?"
Lead is less dense than osmium because of the way their atoms exist in their crystal structures.
"As far as use as a construction and engineering material, the vast majority of the time people don't care how many atoms there are and instead care about something that comes back to the volume."
Not always so in say, chemical or nuclear engineering. But for larger scale applications that is fair enough and you did say the "vast majority." But nothing I said is related to what those people are interested in. I am calling them on saying something that is not accurate. They said the graphene aerogel is LIGHTER than hydrogen. Lighter is a comparison of weight. W = mg where m is mass and g is gravitational acceleration.
If we check wikipedia we find the following about gravitational acceleration, "Neglecting friction such as air resistance, all small bodies accelerate in a gravitational field at the same rate relative to the center of mass.[1] This equality is true regardless of the masses or compositions of the bodies." Since they didn't give any qualifiers we must assume that both materials are being compared under an equal gravitational field. We also find that we must compare them irrespective of air resistance and composition of bodies.
So we can consider g to be 1 which leaves us W = m1, or W = m. Once again, Wikipedia tells us that mass is the quantity of matter in an object.
Thus when you say something is "lighter" than the atom hydrogen you are saying that an equal quantity of matter units has less mass. Graphene is a molecule while hydrogen is an atom. So the comparison is one that only considers atomic mass. Osmium may be more dense than lead but lead is heavier than Osmium.
Now, if that isn't a useful or sensible comparison you shouldn't complain to me, you should complain to the ones who both made the comparison and gave the incorrect conclusion.
Hey dumb ass, X0563511 has it right: the period goes inside the quotes when it's the end of the sentence. Back to summer school for you.
The convention in the United States for decades has been to places periods inside the quotation marks. All others are based on the actual quote. The Chicago Manual of Style, as one of many, recommends this, but most guides point out that the British style placing anything not part of the quote outside of the quotation marks is acceptable but may be seen as unusual to American readers--of all ages.
You can never go home again... but I guess you can shop there.
You are correct that I am a product of 1990's (and 2000's) US public schooling. Not everyone is born into wealth and able to be privately educated.
Despite your implication that my education was inferior, I am able to join a discussion and offer my opinion without attacking participants for little to no reason. I invite you to reflect on what that means in the context of your own education...
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
Ridiculous.
Nobody said anything about graphene molecules having less mass than hydrogen atoms (except you).
What was said (in TFA) was that the graphene aerogel is lighter than helium, which has the plain meaning that a given volume of the aerogel has less mass than the same volume of hydrogen.
(BTW, hydrogen around the earth usually comes in the form of H2 molecules, not single atoms.)
I believe dumb-ass has a hyphen.
The convention in the United States for decades has been to places periods inside the quotation marks. All others are based on the actual quote. The Chicago Manual of Style, as one of many, recommends this, but most guides point out that the British style placing anything not part of the quote outside of the quotation marks is acceptable but may be seen as unusual to American readers--of all ages.
Although putting periods inside quotation marks is recommended by various manuals of style and others recommend putting them outside, I believe that both approaches are misguided
Clarity should be the primary concern in language. Quotation marks are used to indicate that the current passage is repeating something verbatim from another source. It is most accurate to include punctuation inside quotation marks if that punctuation is repeated verbatim. In that case, they are punctuating the original. If they are not from the original source, they should be used outside.
http://yetanotherpoliticalrant.blogspot.com
The second problem is actually the main problem, IMHO. It is not like this kind of lifting agent is going to leak out if the hull is damaged by bad weather, or expand uncontrollably if ship ascends too abruptly.
The hull is damaged, air might leak in and make the structure heavier. The is short of design makes airship rather similar to ships and submarines that move through water. In the event of damage the worry isn't that the contained material (air in the case of ships and submarines) will leak out. The problems is that the outside material (water in the case of ships/submarines, air in the case of a aerogel filled airships) will leak in.
You are also assuming that the outside air pressure wouldn't crush it down to a density that would make it sink.
I would be really surprised if you could just evacuate the stuff and make it float. Some day we'll use evacuated carbon nanostructures for lighter than air, but I don't think we're there yet.
Actually it's funnier than that. It looks like a spam bot that uses the most popular words in forums to spam ads, this case it is "Mycleanyouknowwhat". Let's call it the Vitriol Spam Bot 1.0!
"If Natalie Portman is not measurable, hot grits are Fictitious." - My new signature !
OK, what I think I know is 1) atmospheric hydrogen is H2, so molecular mass is about 2; 2) atmospheric helium is monatomic, so molecular mass is about 4 (not much of the single-neutron stuff on Earth); 3) a given volume of graphene aerogel in the atmosphere contains a lot of air, which is obviously heavier than He; 4) a given volume of graphene aerogel in a vacuum has lower density than He gas at... what pressure? This comparison is pointless. Any gas in a nearly-perfect vacuum is infinitesimally low. Now, if a volume of aerogel in a vacuum is sealed on the surface and after any compression from being surrounded by a fluid at, say, 15psi it still has low density, it might be reasonable to compare it to a gas at 15psi. But saying it's twice as dense as H2 and less dense than He is putting it in a very narrow range.
"Dumb": adjective. "Ass": noun. Usage: correct without punctuation. "That ass is dumb. It is a dumb ass."
By the taping of my glasses, something geeky this way passes
X0563511, did you know that hydrogen is made up of matter, and is thus a material?
On the other side, spelling doesn't matter nowadays, thus your post is immaterial for the context of /.
Questions raise, answers kill. Raise questions to stay alive.
How is it made?
Freeze-casting: take the material, form a gel with a solvent that has a triple point, freeze the gel, sublimate the solvent.
Graphene oxide is hydrophilic, one may try it at home using water. Use a jewelry ultrasonic cleaner to form the gel and your freezer for freeze-drying the gel. As it may take a while to have all the water sublimating, perhaps trying to freeze-cast it as band rather than a bulky form may help. Note: I didn't try it myself (yet)
Questions raise, answers kill. Raise questions to stay alive.
And helium. And a lot of other gasses. The aerogel only stays puffed up because it's got air in it. If you're going to be fair you have to count that as part of the density.
FTFS: "the ultra-light aerogel has a density of just 0.16 mg/cm3, which is lower than that of helium and just twice that of hydrogen."
The Tao of math: The numbers you can count are not the real numbers.
This is why they say someone who eats a healthy diet "eats healthy" instead of "eats healthily".
"I like to eat Italian." => "I like to eat Italian food."
"I like to eat healthy." => "I like to eat healthy food."
So could you please clarify your claim that "to eat healthy" is not valid English?
Peasant.
Myself, I am an evangelical agnostic.
I don't know, and you don't either.
-- Alastair
As an atheist, I don't care that you believe in God or the Tooth Fairy, I just object when your beliefs impact on me.
To have a right to do a thing is not at all the same as to be right in doing it
This is why I love Slashdot. somewhat intelligent arguements about how to properly call someone a Dumbass. Dumb Ass.
Free Pie! The Pie is Also Evil!
You can't rush these things! That has to evolve in the discussion naturally. Wait for someone to call the other a grammer nazi or something.....
Free Pie! The Pie is Also Evil!
If you like "static", keep your old TV. It is not available on new, all-digital TVs.
nice to see my mod stalker got some more points to abuse.
The guy who said the election was rigged won the presidency with the second-most votes.
You are correct, this is, was and has been the academic style for at least the 40 years I have been teaching. Obviously our friend above is misinformed and has probably spread that misinformation around a bit. The fun part of language, however, is that they could end up becoming a new standard if they convince enough people that they are correct. This is the fun that makes me happy that we don't have a controlling body for the English language. (Like the French Academie or the Spanish one whose name slips my feeble mind at the moment)
Subversion of spatial scale luxury decoration ideas.