This is aerogel.
The world’s lightest, that is least dense, solid. This piece has a mass of just 1.22 grams. That is only a few times the mass of the same volume of air, which kind of makes sense because it is 99.8% air. In fact, some aerogels are so light that if you removed all the air from them, they would be less dense than air. I have long been fascinated by aerogel so I actually flew out to Aerogel Technologies in Boston to find out why was aerogel invented. How is it made? Why is it such a good thermal insulator and what is it used for? – Okay, we are going to try an experiment to demonstrate the insulating power of aerogel so over here we have two setups: one with a glass petri dish, and the other one with aerogel on top. – Both are made of silica, but with very different physical structures. We’re gonna see how long it takes to melt these chocolate bunnies with a Bunsen burner. – Now to have a look at this experiment, we have a FLIR T1020 which can see temperatures up to 2,000 degrees Celsius. – Looks like it’s getting pretty hot. – Yeah, you can see that the glass is getting really hot already. And after just a minute: – It’s starting to smoke.
– Okay. – It’s definitely melting and smoking. Oh, yeah, here we go. I would say that’s phase change. – We’ve got a liquid chocolate situation. We have some smoking bunny. Over here, the bunny is actually sort of melting over, and look, there, it’s sort of tilting to the side. – Alright, I think we’re going to call that a melt. – What is that?
– Oh! On cue, on cue. [Laughs.] – I would say that is material fail. – Not only did the bunny melt quickly, the petri dish cracked under the thermal expansion. – Wanna pop it in? – So now let’s try the aerogel. [Music]
– So how is aerogel invented back in? – Back in 1931, a guy named Professor Samuel Kistler had a bet with his colleague Charles Learned. – Now the bet revolved around jellies,
like peanut-butter-and-jelly jellies. Now the thing about jellies is they are actually a combination of liquids and solids. [Music] I mean, they’re mostly liquid,
but it’s embedded within this 3D solid structure. – So if you think of a gel, like jello, has a skeleton with nano-sized pores that gives it its rigidity, and then that’s about 1% of the gel. – So the bet was this: Could you remove the liquid from the jelly? Without affecting the solid structure?
I mean, if you just evaporate the liquid out, well, then the solid structure shrinks, because as you remove liquid molecules, they pull on each other, and they pull on the solid structure around them, basically crumpling it from the inside. Now Samuel Kistler solved this problem in two ways. First, he realized you could replace one liquid with another inside the jelly just by washing it thoroughly. So you could swap out, say, water, for alcohol. And then, if you take the jelly and put it in a high-pressure vessel called a autoclave, – By heating it to the high-temperature, high-pressure point called the critical point of the liquid, that liquid transformed into a semi-liquid, semi-gas called a supercritical fluid. – At this point, there is no longer a distinction between liquid and gas. Those molecules are no longer pulling on each other. – So once you’ve depressurized the vessel, that solid skeleton, that 1% of the mass of the gel, is left behind intact, except for where there was liquid in the pores before is now gas, and that solid skeleton, that nanoporous solid is what we call aerogel. – Kistler published his findings in Nature in 1931. It is getting pretty hot as you can see through the thermal camera. But coming up on three minutes, there’s still no sign of melted chocolate. So we’re gonna pull out a thermocouple and just check the temperature underneath the bunny. Like, underneath the aerogel, and see what, what the flame temperature is. You can kind of see that, that parts of the bunny are getting hot, but it’s not the bottom of the bunny, It’s all the, around the bunny. – Exactly. That convective heat is moving up and around the aerogel, – So you can see the thing is getting red hot.
– And by four minutes, the bunny is looking a little soft. – Still pretty good though, considering how easy it is to melt chocolate. – Can I put my finger here? – Be careful. It’s not that it’s hot, it’s that it’s brittle.
– Right. – But yeah, totally cool to touch, right?
– It is, it is just warm to the touch. – He made aerogels out of all sorts of things. He made them out of eggs.
He made them out of rubber, out of nitrocellulose. And, included in there was silica. Actually right here on the table, I have some examples of some silica gels. This is a, a wet silica gel It’s kind of rubbery so I can just,
you know, carve out a piece. It is 97% alcohol inside of its pores. And then the remaining 3% solid is amorphous silica. Just– – Can I touch it?
– Yeah, absolutely. It’s kind of rubbery. Not that strong. – So was I cracking it there or was it already kinda cracked? – Yeah, you just, no–
– Oh whoa, it’s very easy to break. Very crumbly. – The next step is to replace the alcohol in the gel with liquid carbon dioxide. – We’re about to see liquid CO₂. – Liquid CO₂ has the advantage of being non-flammable, plus it’s got a low critical temperature. – Open it up, and–
– Yeah, I see it flooding in there. – Yeah, it’s flooding in. There it goes.
Just another solvent. [Vibration.] – You can clearly see that it’s so much cooler on top. – What temperature is it on the bottom?
– We’re at 600 right now? – 600 degrees Celsius.
– 600 degrees Celsius, that’s 1250 Fahrenheit right now. – Notice where the bunny is melting. It’s melting right on that edge where the heat’s, like, the flame is kind of crawling up and over. – So, yeah, that’s – Oh! Bunny down! [Laughs.] – Well, not a bad result.
– Not a bad result at all. – I’m interested in in tasting some of this chocolate here. ( – Gross.) – Is it hot? – It’s warm.
– Warm. – And delicious.
– Like fondue. – Mm-hmm. That was great. Once the liquid CO₂ has filled all the pores of the gel, it’s time to take it supercritical. – It was, I would say, a kind of a spiritual experience the first time that I saw a supercritical fluid. – We’ll get to that here. – [Laughs.] I love how much you’re into these autoclaves.
– I love aerogels. To make a supercritical fluid, we can heat this with a hairdryer actually. [Hairdryer blows.] As we approach the critical point, the surface of the liquid becomes kind of blurry. – Weird, huh? – That is like weird waves in there, yeah. I’ll speed it up so you can watch the surface disappear altogether. You’re now looking at the supercritical fluid of CO₂. In this state, the CO₂ can be vented without affecting the solid structure, and what you’re left with is aerogel. ♫ – If you look at aerogel on a light background, it’s almost impossible to see,
because it is pretty transparent. But if you look at it on a darker background, then you can see that it has a slight bluish color. And, it’s bluish for the same reason that the sky is blue, because all those tiny little nanoscale structures, they scatter the light according to Rayleigh scattering. And, the intensity of light scattered is proportional to
1 over wavelength to the power of 4, which means it scatters shorter wavelengths, like blue, much more than it scatters yellow or red. And, for that reason, aerogel looks opaque in the ultraviolet and transparent in the infrared. – Now, what do you think this would look like
if I held it up to the blue sky? What do you think we would see?
Would it look ultra blue? No, it looks yellow. And that’s because the aerogel is actually scattering out that blue light, and so what passes through and makes it to our eyes is the longer wavelengths like the yellows and oranges. It’s basically the same effect as looking at a sunset When you see the yellows and oranges of a sunset, it’s because the blue light
has already been scattered out by the atmosphere the light had to pass through
before it reached your eyes. So effectively looking at aerogel against blue sky
is like looking at a portable sunset. The nanoscale pores of the aerogel are also what makes it such a good thermal insulator. ( – Three.) – That’s awesome. – Does that look hot?
– It’s definitely hot. – You might think that because aerogel is largely comprised of air, like 99% air, that it has the same thermal properties as air,
but that is not correct. It’s actually a better insulator than air is. – That’s because the width of the pores is smaller than the distance air molecules travel on average before colliding with something. Their so-called mean free path. Hence, it’s really difficult for the hot, fast-moving air molecules below the aerogel to diffuse through it and transfer heat to the top of the aerogel. This is called the Knudsen effect.
– It is so weird because you know, you don’t expect something that’s transparent to block the heat that well, but this really does. – And that’s why NASA used aerogel insulation on the Sojourner Rover, Spirit and Opportunity, the Curiosity Rover, and they plan to use it on future missions to Mars. – Why does it need insulation?
– The electronics, because they don’t want the electronics to get cold during the cold nights on Mars – NASA has also put aerogel to more exotic uses, notably to catch dust from a comet
as part of the Stardust mission. – So the particles were traveling about six kilometers per second relative to the aerogel So when they hit the aerogel, because the aerogel’s
a very low density material, very, very porous material, the particles actually enter the aerogel,
and as they travel through the aerogel, they basically break apart the network that makes up the aerogel and they lose energy in the process and eventually come to a stop. This is good for capturing particles, because if a particle like that were to hit a solid surface then it just stops, you know, immediately. – It just vaporizes.
– And vaporizes. – So should we expect to see aerogel in our everyday lives anytime soon? – One of my running jokes is when they build skyscrapers in Antarctica, they’ll use aerogel as thermal insulation. [Both laugh.] – Why do you say that? – Well, because then they’ll really care about how, just how thermal efficient it is
because it would be so cold there. – Right. – So instead of having, you know, ten feet of fiberglass insulation, you could have six inches or something of aerogel. – Scientists are currently working on reducing costs and increasing durability. – And that’s true. They do have some elasticity.
– Okay. – Yeah, so there we go. So it is not hard to break. – They’ve already made a lot of progress.
For example, original silica aerogel is hydrophilic. – There we go. Now this is a hydrophilic aerogel. – So once we’ve done this, is that piece of aerogel ruined now? – Pretty much. – But there are ways to make it waterproof. So if you want to see that and all the other next generation aerogels, then subscribe to the channel and this may be the start of an aerogel trilogy. ♫ [Subtitles credits: 雜碎 Chop Suey, ]
[Translation credits: ]

World’s Lightest Solid!
Tagged on:                                                                             

100 thoughts on “World’s Lightest Solid!

  • September 24, 2019 at 2:33 am
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    Drops it *

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  • September 24, 2019 at 2:53 am
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    This is so cool
    I want to t o u c h it so b a d

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  • September 24, 2019 at 3:35 am
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    Theo's chocolate bunnies being wasted they'd be better off in my stomach lol

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  • September 24, 2019 at 3:46 am
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    Damn, chicken little was right

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  • September 24, 2019 at 3:52 am
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    So, chicken little WAS right… the sky did fall.

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  • September 24, 2019 at 3:53 am
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    Does anyone else just wanna see him try to crush it??

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  • September 24, 2019 at 4:32 am
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    I want shoes made of this

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  • September 24, 2019 at 4:35 am
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    I was thinking about Assassins Creed when I saw this

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  • September 24, 2019 at 5:03 am
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    Aerogel: iam 99.8% air

    Lays: oh! so ur approaching me?

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  • September 24, 2019 at 5:32 am
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    Imagine sleeping on this 😌

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  • September 24, 2019 at 5:58 am
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    Who else thought of biting that and seeing if it was chewy

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  • September 24, 2019 at 8:06 am
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    Now we know what the pieces of sky in Chicken Little were actually made of

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  • September 24, 2019 at 9:01 am
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    No chocolate was harmed in the making of this video

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  • September 24, 2019 at 9:55 am
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    Can u eat it

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  • September 24, 2019 at 10:14 am
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    Lays : our bags are 80% air!
    Aerogel : Are you kidding me?! Those are rookie numbers!

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  • September 24, 2019 at 10:28 am
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    Material : aerogel
    Armor : low
    Elemental resistance : very high

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  • September 24, 2019 at 10:51 am
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    한국인 ??

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  • September 24, 2019 at 12:42 pm
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    My brain: Eat that thing

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  • September 24, 2019 at 12:58 pm
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    1, TUTU

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  • September 24, 2019 at 1:26 pm
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    만져보고싶당

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  • September 24, 2019 at 2:46 pm
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    What about a single piece of hair

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  • September 24, 2019 at 3:06 pm
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    For some reason I misread “lightest” as “largest”

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  • September 24, 2019 at 3:22 pm
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    한국 자막 고마워요!

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  • September 24, 2019 at 3:41 pm
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    it looks like a jello

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  • September 24, 2019 at 4:36 pm
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    Are you somehow related to Elon Musk? why do you look like him sometimes?!

    Reply
  • September 24, 2019 at 5:45 pm
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    우연히 추천영상에있길래 눌렀더니 에어로졸.. 서브나우티카에서 자주 봤던거라 왠지 반가움ㅋㅋㅋㅋㅋㅋㅋㅋ 게임에선 젤주머니랑 루비?였나? 그렇게 만들면됐는데 현실에선 역시 복잡하군요 신기방기..!

    Reply
  • September 24, 2019 at 6:20 pm
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    Aerogel:iam the lightest thing ever created
    OUYA:hold my warranty cards

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  • September 24, 2019 at 7:40 pm
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    CaN i EaT It

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  • September 24, 2019 at 7:57 pm
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    Air is a good insulator, vacuum is a good insulator.

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  • September 24, 2019 at 9:12 pm
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    World lightest solid is my di-
    Wait let's not go that far

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  • September 24, 2019 at 9:30 pm
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    Hi

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  • September 24, 2019 at 10:27 pm
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    Amazing! You just earned a new youtube fan right here!

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  • September 24, 2019 at 11:12 pm
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    So its just clear jello

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  • September 24, 2019 at 11:12 pm
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    Glue sticks

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  • September 24, 2019 at 11:34 pm
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    The lightest solid are Victoria secret models

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  • September 24, 2019 at 11:45 pm
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    Think of the light weight thermo clothing ….

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  • September 25, 2019 at 1:08 am
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    I want to eat some

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  • September 25, 2019 at 1:39 am
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    next; Aerogel Dildos… it's just like you husband… because you can barely tell it's in there.

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  • September 25, 2019 at 1:42 am
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    3:41 – Ladies and Gentleman… the all screen… iPhone 16 prototype 1A…

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  • September 25, 2019 at 1:53 am
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    I bet this'll be at least somewhat useful when a climate crisis happens involving heat. B-)

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  • September 25, 2019 at 1:54 am
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    This is also known as the reality stone

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  • September 25, 2019 at 2:17 am
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    The bunny died at exactly six minutes. Coincidence? I THINK N O T !

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  • September 25, 2019 at 2:23 am
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    Wow this is better than electricity 🙂

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  • September 25, 2019 at 2:28 am
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    10:40
    My brain : "Hold Up"

    (Fallout jokes)

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  • September 25, 2019 at 3:50 am
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    Why do I keep watching this

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  • September 25, 2019 at 3:58 am
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    i feel smart now

    Reply
  • September 25, 2019 at 4:00 am
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    Aerogel: 1.22 grams

    Feather: 0.0082 grams

    Feather: am a I joke to you

    Reply
  • September 25, 2019 at 4:20 am
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    MAKING FLYING CAR WITH THIS MATERIAL GONNA BE EASY OR NOT?

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  • September 25, 2019 at 6:31 am
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    神奇

    Reply
  • September 25, 2019 at 6:39 am
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    Idk why But I wanna eat it

    Reply
  • September 25, 2019 at 7:33 am
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    Yo I think he's chocking John Cena at 8:33 (pause)

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  • September 25, 2019 at 8:12 am
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    “Basically crushing it from the inside”
    That’s my heart 💔

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  • September 25, 2019 at 8:23 am
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    So in future Aerogel will be our glass?

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  • September 25, 2019 at 9:37 am
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    저거 이해되는사람 있냐;;

    Reply
  • September 25, 2019 at 9:59 am
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    I wanna eat it

    Reply
  • September 25, 2019 at 10:59 am
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    I thought it was nata de coco at first

    Reply
  • September 25, 2019 at 11:11 am
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    Can be obtained from Area 51 raid

    Reply
  • September 25, 2019 at 12:03 pm
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    Aerogel or a random Lays bag, who has more air…

    Me: i see this the same

    Reply
  • September 25, 2019 at 12:10 pm
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    코코팜 알갱이가 존나커지면 저런느낌일까

    Reply
  • September 25, 2019 at 1:53 pm
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    한국어 자막 감사합니다! 😊 에어로졸에대해 알게되었고 에어로졸에대해 더 알고싶게하는 영상이네요 구독했어요!

    Reply
  • September 25, 2019 at 1:59 pm
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    Fake! That solid is a paid actor!

    Reply
  • September 25, 2019 at 3:22 pm
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    我唯一在這打中文的人嗎?

    Reply
  • September 25, 2019 at 3:40 pm
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    Aerogel is sooo cool

    Reply
  • September 25, 2019 at 3:51 pm
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    I bet this is what's going to be used to make super light pc mice some day

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  • September 25, 2019 at 6:09 pm
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    so if you put hileom insted of air in there it will be even more lightere ?

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  • September 25, 2019 at 7:10 pm
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    we have a liquid chocolate situation , a melting bunny!

    moments later : bunny down!

    Reply
  • September 25, 2019 at 7:19 pm
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    RIP Oppy

    Reply
  • September 25, 2019 at 7:24 pm
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    0:38 wait thats illegal

    Reply
  • September 25, 2019 at 7:51 pm
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    lays wants to know your location

    air increased by 100%

    asthma decreased to 0%

    restoration 100

    Reply
  • September 25, 2019 at 10:38 pm
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    Shout out Boston 617

    Reply
  • September 25, 2019 at 10:59 pm
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    I want to bite it

    let me bite it

    Reply
  • September 25, 2019 at 11:20 pm
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    Gentleman, I want to learn more about Aerogel. Can you help me plz!

    Reply
  • September 25, 2019 at 11:26 pm
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    Love this but where can I buy one of those aerogel cubes? My kid looooves your channel (He's 7 and science mad!) And I thought this would be a great thing to get him 🙂

    Reply
  • September 26, 2019 at 12:05 am
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    So this is what’s in a bag of lays chips

    Reply
  • September 26, 2019 at 12:31 am
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    Marshmallow is also veeeeeeeeeery light..!

    Reply
  • September 26, 2019 at 1:54 am
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    I wanna squish aerogel!

    Reply
  • September 26, 2019 at 2:53 am
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    I wanna eat that wtf

    Reply
  • September 26, 2019 at 3:38 am
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    The dish cracked because of the burning sugar

    Reply
  • September 26, 2019 at 4:47 am
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    who else wants to touch it..

    Reply
  • September 26, 2019 at 5:14 am
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    here am i at 3 am when i should sleep :v

    Reply
  • September 26, 2019 at 7:16 am
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    I cut the smallest piece of a paper and it didn’t even weigh so is it the lightest thing on the planet.

    Reply
  • September 26, 2019 at 8:12 am
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    It's looks like cloud

    Reply
  • September 26, 2019 at 8:32 am
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    2 choco bunnies were harmed in the making of this video… what's the number for SPCA hotline again?

    Reply
  • September 26, 2019 at 8:40 am
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    아 순간 사나고인줄알았네

    Reply
  • September 26, 2019 at 10:34 am
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    R.I.P chocolate bunny

    Reply
  • September 26, 2019 at 10:47 am
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    How abo—

    Ants : 𝕪𝕠𝕦 𝕜𝕚𝕕𝕕𝕚𝕟𝕘 𝕞𝕖𝕙?

    Reply
  • September 26, 2019 at 11:41 am
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    This is so high brow and intelligent. I always quickly revert to this video when I hear the wife approaching.

    Reply
  • September 26, 2019 at 2:15 pm
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    Aerogel: World's lightest solid

    Paper: am I a joke to you?

    Reply
  • September 26, 2019 at 2:26 pm
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    Petri dish = my heart when I realized my chocolate bunny was hollow.

    Reply
  • September 26, 2019 at 3:16 pm
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    Put in on future's gaming phone 👀👀

    Reply
  • September 26, 2019 at 3:49 pm
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    ah yes,

    Enslaved air

    Reply
  • September 26, 2019 at 3:50 pm
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    Pictures would take the cake invisible this work you can know all about it and have the name in the archives but you need to know how echno through many places at ones time yes time here but then you could say in a hour I'm running even now every bit time depends on ones discretions i like to think out side the dimensions

    Reply
  • September 26, 2019 at 5:14 pm
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    겁나 사기 같네

    Reply
  • September 26, 2019 at 8:26 pm
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    "If you removed all the air from it, it would be less dense than air." This would imply that the non-air component would be less dense than air, which would mean it would already be less dense than air before you removed the air from it.

    Reply
  • September 26, 2019 at 11:48 pm
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    6:18 It's hard to remember that you've gotta tell some people to NOT eat the science experiment.

    Reply
  • September 27, 2019 at 12:31 am
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    알수없는 유튜브가 날 여기로 불렀다

    Reply
  • September 27, 2019 at 1:44 am
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    no oppy was harmed in the making of this video

    Reply
  • September 27, 2019 at 1:45 am
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    I
    Wanna
    Touch
    It
    Please

    Reply
  • September 27, 2019 at 4:05 am
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    ナタデココ?

    Reply
  • September 27, 2019 at 4:14 am
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    Soooo you are basically holding a cloud then…..

    Reply

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