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The Amazing Properties of Aerogel
RideMax writes "We all know NASA is using a substance called 'aerogel' in the Stardust spacecraft to catch pieces of the Wild-2 comet. The NYT is running an article about some other amazing aerogel properties. My favorite quote: 'It's the lowest density of any solid, and it has the highest thermoinsulation properties. Though it would be very expensive, you could take a two- or three-bedroom house, insulate it with aerogel, and you could heat the house with a candle. But eventually the house would become too hot.'" We've looked at Aerogel before.
But does it's insulation properties beat that of Trellium-D?
And why did you staple the trout to the RAM?
If you goddamn kids would close the goddamn door!
I have been pwned because my
I think Mr. Kelley has done a masterful job describing modern day industrial design in terms and examples we can all relate to. He makes it clear why innovation in our high tech world is as much art as science. And why his company delivers 'marketable products' for their clients and not 'products looking for a market'. I think there are lessons here for a wide spectrum of engineers, marketeers, and anybody responsible for a (successful!) product or service coming to market. The book is interesting and fun to read.
Though it would be very expensive, you could take a two- or three-bedroom house, insulate it with aerogel, and you could heat the house with a candle.
Seems to me that in this case, having a few lights left on or PC with a hot CPU left running would quickly make things uncomfortable
What if it was only used to certain walls where leakage was most common?
I'm just curious as to what the R-factor would be. The article does not specify this.
aka Vaporware... Made of 99.6 percent empty space, the little cube is indeed barely there, with a density one-hundredth that of the hand that holds it.
- It is 99.8% Air
- Provides 39 times more insulating than the best fiberglass insulation
- Is 1,000 times less dense than glass
- Was used on the Mars Pathfinder rover
And a cool picture of aerogel in somebody's hand.--
For news, status, updates, scientific info, images, video, and more, check out:
(AXCH) 2004 Mars Exploration Rovers - News, Status, Technical Info, History.
Seems like quite a few successes are discovered by mistake.. in this instance, finding a rejected material from nuclear testing.
It also has incredible compressive strength. "It can take 2,000 times its body weight without damage," Dr. Tsou said. NASA's Web site shows a 2-gram cube of aerogel (less than 0.1 ounce) supporting a 2.5-kilogram brick (about 5.5 pounds).
That particular example doesn't seem that impressive, I used to build balsa wood structures that would hold over 600 lbs(~270kg), with only 15 grams of balsa wood and glue, with strict rules on how it could be built. The world record is somewhere in the 1500 lb mark with a similar weight of wood.
There needs to be some air circulation, and that will lead to heat loss.
-Libertarian secular transhumanist
Very good Aerogel FAQ.
--
For news, status, updates, scientific info, images, video, and more, check out:
(AXCH) 2004 Mars Exploration Rovers - News, Status, Technical Info, History.
make the coffee in the morning, put it in your thermos, and it is still warm for the drive home.....
Try making Aerogel in Zero G under a 45 second time constraint. Now that takes talent.
IWARS.
People, in general, disappoint me. Politicians even more so.
Maybe I'll make clothing out of it for my friends in Alaska, the transparency issue is a plus!
1888 Franklin St.
Here is the link to all the cool pictures at NASA's website.
Cheers
Nobody cares about your Odyssey of the Mind days. That ratio is actually pretty impressive for a solid material...imagine what it could hold if it used physics such as trusses and lamination, like you did.
The grad student had a nervous breakdown because he was having a little trouble? Damn they should put him incharge of their army!
I heard of Aerogel long ago, but I assume the issue is the same as then - price. Is it getting better, or is it still for those really really extreme projects only? It's cool in the same way superconductors are, but you don't get to play around with them...
Kjella
Live today, because you never know what tomorrow brings
let me get this straight....virtually unbelieveable insulation at the coldest of temperatures...creating super greenhouses/habitats and so forth...
improves the desalination of seawater plants a thousand fold...
my god....all we have to do is find a cheap or easier way to produce (like we do with virtually everything in the world in the free enterprise system) and we can offer virtually energy free habitats (excess heat can be channelled into electronics and solar can pick up the rest) - as well as a cheap water supply for the world...
christ...someone get me some chemists and a few venture capitalists.....this is incredible... - and it's real and now...not like those carbon nanofibers people want to use to create space elevators...
pax
RB
----------
ah honey, we're all resplendent - Bill Mallonee
Buy some aerogels, made in Germany. We know that they have great insulating properties, but is it insulating per unit weight? If that is the case, it is probably because they weigh so little and therefore they don't allow any convective cooling. All the cooling has to be by temperature conduction, which is not efficient in air.
maybe you could change the thermostat or open a window. bet that would work.
You know what I'm talkin' about. *Wink*Wink* Nudge*Nudge* :P
Maybe this is nothing new, but did you just bypass nyt's registration?
The article doesn't touch on it, but the NASA FAQ mentions this unique property...
Q: What happens if I touch it?
A: Silica aerogel is semi-elastic because it returns to its original form if slightly deformed. If further deformed, a dimple will be created. However, if the elastic limit is exceeded, it will shatter catastrophically, like glass.
I wanna play with it so bad!!
Some cool shots.
or maybe that's because we need more scientists and product specialists to take an interest....
nt
Here's a nerdy factiod about aerogel that might help your processor speed.
There has been some close research into using substances like aerogel to improve processor speeds. Apparently the substances can be used as very efficient insulators between traces and components. This is because aerogel and substances like it are mostly made of air, which has a very high dielectric constant so aerogel itself is a very good insulator.
It's better described here
Anyone care to place a bet on how long it takes the US to figure out how to make aerogel an efficient means of killing a bunch of people?
This informative comment was lifted from a comment made the last time aerogels were discussed on slashdot (see the original comment here).
Is that Astrogel in your pocket, or are you just happy to see me?
*rimshot*
This space for rent.
PASADENA, Calif. -- On Jan. 2, NASA's Stardust spacecraft flew through a 14,000-mile-an-hour hail of debris from the Wild 2 comet. Under this withering barrage, the ship's objective was not only to survive, but to use a collector made of a bizarre substance to gather an unaltered sample of five-billion-year-old dust and gas ejected by the comet.
This seemingly impossible task has been the 20-year quest of Dr. Peter Tsou, the deputy principal investigator for the Stardust. On a quiet afternoon at the Jet Propulsion Laboratory, Dr. Tsou showed off a three-centimeter cube of silica aerogel, the substance that he used to catch the comet's tail.
At around 0.003 grams per cubic centimeter of material -- only about three times as dense as air -- aerogel is pure silicon dioxide. Not only is it the least dense solid in existence, it is also such a remarkable insulator that a layer of it surrounds the most vital electronics on the Mars rover Spirit. But the most striking feature, at least to the naked eye, is that up close, the cube looks like a blurry hologram.
"When you look at this," says Dr. Tsou, holding the aerogel up, "you don't know where to focus. That's why some people call it solid smoke."
Made of 99.6 percent empty space, the little cube is indeed barely there, with a density one-hundredth that of the hand that holds it.
To make this strange material, scientists start with a liquid alcohol like ethanol and mix it with silicon dioxide to form a gel. Then, through a process called supercritical drying, the alcohol is forced out of the gel, typically with high-pressure carbon dioxide. With this drying process, the gel does not collapse or lose its volume. It appears holographic because the silicon dioxide scatters shorter wavelengths of light much like air in the daytime sky.
In the mid-1980's, Dr. Tsou ventured to the Los Alamos National Laboratory in search of a material that would allow him to collect particles moving at three to six miles per second without destroying either the particles or their collector. "I approached many scientists," he said. "They said, `Come on, that's ridiculous.' At J.P.L., we have a tech guru. I paid him to do a report, and he said, `It's not possible.' "
Dr. Tsou had considered using many thin foil layers or a polymer foam to catch the particles, but in space, radiation and temperature extremes quickly degrade foams. Because foams and foils are opaque, finding the captured interstellar particles would have been a problem.
While at Los Alamos, he said, he noticed a cube of an odd material on a laboratory windowsill. It was a form of aerogel that Los Alamos had tested and rejected for its nuclear fusion experiments.
The material was not new. In 1931, Steven S. Kistler was a pioneer in making the substance at the College of the Pacific in Stockton, Calif., now the University of the Pacific. But, Dr. Tsou said, the material was not used much, except in powdered form as a nontoxic anti-caking agent for food.
In the 1980's, Dr. Tsou and others began to work with the material. "It has 14 Guinness Book of World Records-type properties," Dr. Tsou said. "It's the lowest density of any solid, and it has the highest thermoinsulation properties. Though it would be very expensive, you could take a two- or three-bedroom house, insulate it with aerogel, and you could heat the house with a candle. But eventually the house would become too hot."
Additionally, aerogel slows soundwaves to about 10 percent of their speed in air, and because it has such a vast surface area for its volume, its use as a filtration agent could increase the capacity of desalination plants a thousandfold.
Because aerogel is transparent and releases light when struck by certain high-energy radiation, it provides an excellent means of counting atomic particles. It also has incredible compressive strength. "It can take 2,000 times its body weight without damage," Dr. Tsou said. NASA's Web site shows a 2-gram cube of aerogel (less than 0.1 ou
While I'm sure aerogel has many pracitcal uses (trying not to fall asleep here), the "cool" factor is also very high. I've seen some of her samples, and everything the article says is correct. It's so light it feels like the wind could take it; in fact, if you drop it in water, I think it dissolves. Since the material is so expensive, it's obviously something you don't want to do, since every last piece is precious.
As you might imagine, a material that's ultra-light and 'holographic' has artistic applications, too. The "brain" image made it onto the cover of Nature neuroscience, and wouldn't look out of place in a design magazine. When you see it up close, the image seems to be 'embedded' in the material, even though it's so light you could easily crush it with your hand. The airiness and delicacy of the material makes the image that much more striking.While we're all attuned to the utilitarian value of materials like this, it's always neat to see what people outside of engineering can do with them.
Though it would be very expensive, you could take a two- or three-bedroom house, insulate it with aerogel, and you could heat the house with a candle. But eventually the house would become too hot.'
if you have the smallest crack in your house, then air will be allowed to escape. this means that you do not have a closed system. assuming that air is an ideal (or even a van der Waals) gas, if it heats up, it expands. this means that air escapes and the temperature sinks. hence you would NOT heat up your house with a candle. just think of the equation pV = NRT, i.e. T ~ 1/N (temperature proportional to 1/number of particles).
as a matter of fact, when you heat up a house, the air is not what keeps it hot. it is the items, such as walls, and stuff, which irradiate the heat off and so warm the room. if you now make walls out of a completeley nonheatconducting stuff, would it still work? i am not sure...
Check it out - this auction on Ebay is selling a 4-6 Cubic inch chunk of Aerogel with a "Buy it Now" price of $160. Considering the auction says it costs about $200 per cubic inch to make, thats a deal. I'm guessing some /.'er with deep pockets will be buying this pretty soon!
Looking for hardware (Currently need: Large Etch-a-Sketch) Have one? See my journal!
you can buy this stuff from MarkeTech for the rock bottom price of $975 a 4x8x0.5" piece.
I'll let someone else figure out how expensive an entire house would be to insulate.
Note that this isn't even the really good stuff (the average density of the commercial stuff is only 99.9% air, while the hi-tech versions used by NASA can be as high as 99.99% air or more)
For those of you who like stupid science tricks/supercheap climate control, here's a trick for how to heat and cool a house without using any energy (outside of what's free from the Sun):
/ blackbody/bbody.html), which gives 300-500W/m^2 at typical Earth temperatures (over 400W/m^2 heat loss at typical room temperature).
First, some background on black body radiation. All matter radiates some light, based on its temperature. By basic thermodynamics, the amount of radiation that a color of matter absorbs in a given frequency range (as opposed to reflects) is directly proportional to how much it radiates (as compared to a perfect black body of the same temperature).
The sun only radiates on a fairly small set of frequencies, and that set is very different from the frequencies at which a black body at room temperature radiates. If you build a panel of a material that is perfectly absorbent in the frequencies on which the Sun radiates (perfect black body), but reflects in the remaining frequencies (perfectly white on the blackbody frequencies of room temperature), it will lose very little heat to radiation, but absorb a lot from the sun, and it'll get very hot. If you take a body that reflects radiation in the colors the sun emits (white), but absorbs/radiates elsewhere (black), it'll get very, very cool, even in bright sunlight. You can get pretty close to the full 1000W/m^2 of heating (level of Sun's radiation hitting the earth). In cooling, you get pretty close to the ideal from Stefan's Law (http://www.egglescliffe.org.uk/physics/astronomy
This means that you can theoretically heat or cool a house with just a painted square on the roof a few square meters in area, if you could just create a material of the right color.
Problem is the guy who came up with this (and showed it to me) was a physicist and not a chemist, and had no idea how one would go about creating a material whose color was that well controlled.
Still a nifty concept, eh? If you could make this, it would save a ton of energy, since you'd no longer need to burn gas to heat and use electricity to cool -- just flip a panel on your roof, and the temperature changes (although for heating, the house would need to be well enough insulated to last the night).
Ref: The Third Industrial Revolution by G. Harry Stine.
since occupants require at least some outside air for ventilation, and the heating of that air has nothing to do with the insulation of the structure.
How good is aerogel as a sound insulator?
See CDT Water for one practical, functional application of aerogel.
In short, they push contaminated water through aerogel and use electrodes to pull ionic molecules apart. The ions get caught in the aerogel mesh, and the purified water flows through. At least, that's my layman's understanding of it.
Cheers
-b
If I wanted a sig I would have filled in that stupid box.
I hope that NASA fills the voids in the space shuttle with this stuff now.
It was suggested for LMCO's Venture Star as far back as 2000.
I am the unwilling control for my Origin.
Maybe I'm missing something, but elsewhere they said "But, Dr. Tsou said, the material was not used much, except in powdered form as a nontoxic anti-caking agent for food."
If it's so expensive, what kind of food exactly were they using it on? Caviar?
This Space Intentionally Left Blank
It might not be flexible, but it's very light. If it can catch dust flying at 14,000mph, surely this would be the perfect material for a bulletproof vest.
I ran a benchmark on my quantum computer, now I can't find it anywhere!
Try these guys (no, I don't have anything to do with them).
/Styx
I think you've just pointed out the basis (and the base) for the new "levitating" G5 models.
Tweet, tweet.
From Aerogel section of Stardust Overview
If Aerogel is that good at insulation, screw the candel, i'll just rely on the body heat of myself and others :/
Giving IE users a taste of their own medicine since 2005 - http://pods.-is-a-geek.net/
Is it me, or is this the first NYT article that we have not had to register for?
Perhaps they realised that on certain days their database gets populated with about 50,000 Mr F*ck You's with an email address of abuse@nytimes.com.
It can be used as a dessert topping and floor polish.
I'm sure it'd be perfectly safe!
What I have not seen is the application in areas that weight would make a difference, cars, planes, and maybe even clothes.
In clothes, you can have the equivlent in a down jacket in the thinkness of a windbreaker. It would be light as a feature, and not be subject do damage by exteme normal wear.
Of course, everyone on
Fight Spammers!
until some corporation buys the patents or rights to commercially manufacture it, and charges 20 times what its really worth for it, and then this awesome technology will fade into obscurity because no-one can afford it
it has an aerogel core... with wings!
To keep this vaguely on topic, I'll bet FedEx would hate me if I tried to ship several cubic meters of this stuff, since they charge by weight.
Hear recorded Slashdot headlines on your phone! New service beta testing. Just call (248) 434-5508
A few years later, Kistler left the College of the Pacific and took a position with Monsanto Corp. Shortly thereafter, Monsanto began marketing a product known simply as "aerogel". Monsanto's Aerogel was a granular silica material. Little is known about the processing conditions used to make this material, but it is assumed that its production followed Kistler's procedures. Monsanto's Aerogel was used as an additive or a thixotropic agent in cosmetics and toothpastes. Very little new work on aerogels occurred throughout the next three decades. Eventually, in the 1960s, the development of inexpensive "fumed" silica undercut the market for aerogel, and Monsanto ceased production.
--- source
You could heat your whole house with a PC! If it got to hot you'd have a good excuse to liquid-cool it!
;)
Even better!! Instead of having your PC control the heater, it could be the heater!
Jaysyn
There is a war going on for your mind.
Is this substance edible, and if so can add artificial cherry flavoring without altering its' thermoinsulation properties? The Mac OS X spell checker does not recognize the word, "thermoinsulation", and yet NASA loves Macs. Go figure.
From article"and you could heat the house with a candle"
Does this mean you can now cool your house with an icecube?
"Though it would be very expensive, you could take a two- or three-bedroom house, insulate it with aerogel, and you could heat the house with a candle. But eventually the house would become too hot."
Great. I'll need to get an outdoor case mod for my dual Athlon.
"Derp de derp."
"You could take a two or three bedroom house, insulate it with aerogel, and you could heat the house with a candle."
Well, sure, anybody can point out the obvious "if you have a crack in your house" stuff, but the idea is still valid. So, don't go pulling out pivnert from 10th grade chemistry and using that as your basis for second-guessing an illustrative statement.
However, your house would STILL get too hot, even using PV = nRT. V here is constant. R, of course, is the Rieberg constant, the value of which I don't know off-hand. As long as no air leaks out, then as T goes up, P goes up accordingly. But T is on an absolute scale. Kelvins, here. 293.15 K is room temperature, 20 degrees C, and if you heat that up to 30 degrees C, 303.15 K is, in terms of proportionality, not too much of an increase, but hotter than is comfortable, i.e. too hot. Then particles, due to the pressure differential between outside and inside, want to leak out that crack. And what's happened? THE TEMPERATURE HASN'T DECREASED. n in PV = nRT has gone down in order to bring P down to atmospheric pressure outside. Oh, dear, T is higher, and nothing's leaking out! This, silly head, is why it's possible to heat a house in the first place. By your reasoning, a house could never be a different temperature than outside! Which, thank goodness, isn't the case.
And then, of course, "as a matter of fact," the air is exactly what keeps it hot, and any other thermally insulative materials, i.e. fiberglass or aerogel. When you heat up a house, you run air into a furnace, heat it up, and then pump it through the rest of the house. A candle would heat up the air immediately above it (rising products from chemical reaction) and that air diffuses throughout the house, heating it up. Just like your furnace. True, there's radiative heating from the candle as well, but compare the difference in heat when you stick your finger an inch above a candle vs. an inch to the side of it. Radiative heating is universally dispersive. Convective goes straight up. BIG difference between the two there. Oh, well, it looks like a candle COULD heat up the house insulated with aerogel.
Yes, I am a physicist.
Can't remember where I read about them, but Aspen Aerogels claims to have greatly reduced the price of making aerogels.
except for that shattering part.
I've already beaten anti-slash's trolls and flames like it was an off colored step child that stutters.
The amazing properties of KY aerogel
"Researchers at the University of New Mexico, lead by C. Jeff Brinker and Doug Smith, and at other institutions have become increasingly successful at eliminating the supercritical drying step used in aerogel production by chemically modifying the surface of the gel prior to drying. This work lead to the founding of Nanopore to commercialize lower-cost aerogels." ...
Though it would be very expensive, you could take a two- or three-bedroom house, insulate it with aerogel, and you could heat the house with a candle. But eventually the house would become too hot.'" We've looked at Aerogel before.
If the above is true, then, standing in a insulated house would ultimately heat it to 37oC which would be unbearabable as well.
Trolling using another account since 2005.
YOu wouldn't want to let a fart rip in that house either, it just would never dissipate.
public final transient String president = DUBYA;
I wonder how that compares to Aerogel as far as insulating, and other properties.
Any drywall installers on Slashdot using Aerogel?
This sounds almost like those beds that they try and hawk me at night made from "NASA material"...
Any Thoughts?
"Air molecules don't have room to vibrate"? In other words, their temperature magically drops to 0 Kelvin? What I think he is trying to say is they don't have room to convect. Molecules vibrate as a function of temperature. Even if the air molecule were chemically bonded to something, it would still vibrate as a function of temperature.
It's a doped Alumino-silicate. Very impressive making one wih such a vacancy in the structure, and very impressive that it doesn't require the solvent to be in place to maintain the structure.
But, it must be a very hard material to work with, as it is probably the most brittle material know.
Would it be possible to take a piece of aerogel, and remove some of its interior (i.e., make it vacuum), and obtain something solid, floating in air?
http://images.google.com/imgres?imgurl=www.anomali es-unlimited.com/Science/Images/Gel.jpg&imgrefurl= http://www.anomalies-unlimited.com/Science/Aerogel .html&h=247&w=391&start=2&prev=/images%3Fq%3Daerog el%2Bnasa%26svnum%3D10%26hl%3Den%26lr%3D%26ie%3DUT F-8%26oe%3DUTF-8
g ht now.com/news/n0205/08aerogel/aerogel.jpg&imgrefurl =http://spaceflightnow.com/news/n0205/08aerogel/&h =285&w=398&start=9&prev=/images%3Fq%3Daerogel%2Bna sa%26svnum%3D10%26hl%3Den%26lr%3D%26ie%3DUTF-8%26o e%3DUTF-8
t /c nn/2002/TECH/space/05/09/record.gel/story2.light.g el.jpg&imgrefurl=http://www.cnn.com/2002/TECH/spac e/05/09/record.gel/&h=168&w=220&start=19&prev=/ima ges%3Fq%3Daerogel%2Bnasa%26svnum%3D10%26hl%3Den%26 lr%3D%26ie%3DUTF-8%26oe%3DUTF-8
or
http://images.google.com/imgres?imgurl=spacefli
or
http://images.google.com/imgres?imgurl=i.cnn.ne
Air-o-gel sounds more appropriate. When they swap 99.8% Air with with a 99.9999% vaccum THEN I'll be impressed. Except they are doing that already, and I am indeed impressed with the results.
The extremely high R values being quoted are possibly the result of using evacuated Aerogel in panels or other sealed structures.
Forget thrust, drag, lift and weight. Airplanes fly because of money.
NASA's statement is a mere "catch phrase". They probably just studied the thermal conductivity of aerogels and figured out how much energy it conducts. Then they looked at how much energy a candle produces. Then they came up with a selling phrase...
I should have been more precise: when I wrote you cannot heat a house with a candle, I meant: once you turn the candle off, the room should be cold again (in analogy to the crappy heaters in the US). After all you do not have an equilibrium state and air flows out of the house. Radiation will not do much either, because the walls cannot store the heat as they are not conducting. While the canlde is on, the room would be "warm", just like a fire in the woods keeps yu warm.
Too bad you are a physicist. You make us look bad.
Pff thats nothing you novice. I could suspend many tonnes on top of a sheet of metal weighing a few grams. No glue or anything.
I once saw an aerogel which was made in a helium atmosphere. It flew just like a balloon, eventually the helium escaped though.
Government of the people, by corporate executives, for corporate profits.
Oooh ahhhh, I'm so leet. A friend at work had a few samples of the stuff a couple years ago. I recall that although it was extremely light, it fell quickly when I dropped it from hand to the other. These were small pieces, about an inch on a side, so they had little frontal area for their mass. I suspect that a typical birthday balloon weighs even less than the same volume of aerogel. Another thing was that they were quite fragile, and absolutely rigid. I did not break any, but it was obvious that I could crush it into dust if I squeezed just a little too hard. After handling it, I had some miniscule crunchy particles on my skin, and probably a lot more I couldn't see, and I got the sense that going without a respirator if you worked with the stuff would not be a good idea. If I'd had a blowtorch handy and a big enough chunk of aerogel, I'd have been unable to resist doing the blowtorch-against-the-hand trick.
I'll bet FedEx would hate me if I tried to ship several cubic meters of this stuff, since they charge by weight.
You haven't done much freight shipping, have you? You'll be billed out the ass for a little thing called "dimensional weight" - which in layman's terms means "ha ha, we charge you a fortune for trying to ship a massive empty balsa wood crate".
The way it works is, if something takes up too much space - you get charged for the space no matter how light the item you're shipping is. A 200LBS engine, for example, will cost MUCH less to ship than 200LBS of pre-inflated mega fun balls (so why are those things so cheap anyway?).
Considering the mass to density ratio of aerogel, if large chunks could be produced cheaply, it would still be the MOST EXPENSIVE STUFF TO SHIP on the planet. I doubt it's anything to worry about anyway... Doesn't look like this stuff is getting cheap anytime soon.
---
DRM is like antifreeze, to the MPAA/RIAA it's sweet, to the consumers it's poison.
Powder is cheap, but the bulk aerogel made from it is a little bit of a trick.
Iron is pretty cheap too, but a single perfect crystal of appreciable size starts to make Platinum look positively affordable. Or graphite to diamond.
It's not so much the atoms that make many things expensive so much as how they're put together.
C'mon, anyone can tell that the picture was faked in a studio, it's obvious from the shadows cast by the so-called "aerogel". Just one more NASA conspiracy to convince us that they spend our tax dollars on worth subjects. Hrghmh.
Ceci n'est pas une signature
You mean Fedex will *pay* me if my shipment
is lighter than air? Kewl!
You can see the NASA aerogel at the Deep Space Communication Complex at Tidbinbilla (http://tinyurl.com/36rh3).
I know it probably isn't that exciting, but the place is well worth a visit (and it is free!).
J
As far as I can remember from some popular science books if you look at angstrom scale or less you find out that what looks like solid is actually empty space filled with small widely spaced entities of very small and fuzzilly defined boundaries
I'd love to have a little cube of this on my desk. Anyone know where you might be able to buy some?
"Things are more moderner than before- bigger, and yet smaller- it's computers-- San Dimas High School football RULES!"
err...
R in this equation is the universal gas constant.
ie. 8.314 m^3.Pa/mol.K
Don't know what you mean by "Rieberg constant" but the Rydberg Constant is used in the Balmer formula for the spectral lines hydrogen.
Aerogel will die for your sins. It is the Fifth Element.
Some awesome pictures;
"The Flower"
"Six Aerogel Nanocomposites"
"Magnetic Aerogel"
"Photoluminescent Silicon on Silica"
"Carbon Nanostructure in Aerogel"
General Info / Main
I think we can keep recursing like this until someone returns 1
1 cm = 1/100 m
1 cm3 = (1/100)^3 m3 = 1/1,000,000 m3
1,513,333 cm3 = (1,513,333 / 1,000,000) m3 = 1,5 m3
Still too big to fit in anybody's ass (except the goatsie)
Combine aerogel with the various forms of graphite foam, and you can do "anything", all lightweight.
The solution is already well-known as well. You set up a condensor on your intake baffle and an evaporator on your exhaust baffle. Fresh air blowing into the house gets heat transferred to it and stale air getting blown out of the house transfers its heat. You use freon, of course, to transfer the heat from the exhaust baffle to the intake baffle.
Use some pretty high-powered fans, of course, because you want to make sure your air is flowing the right ways.
Not that this system would significantly affect your heating/cooling bill, since it's just another air conditioner to pay for.
Like what I said? You might like my music
The problem is that the aerogel LOOKs like it was created in photoshop or 3d studio. Soft, blurred edges, low contrast, strange colors, ect.
But it looks as strange in real life.
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
I recall that although it was extremely light, it fell quickly when I dropped it from hand to the other
Welcome to gravity, its pretty much the same for everybody on earth.
Special Relativity: The person in the other queue thinks yours is moving faster.
Wouldn't it be rather stale by then?
Of course it's also necessary to compare the total available heat energy in a candle (as in the maximum amount of heat energy it can create by burning), the total mass of air in the house, and the specific heat capacity of air at room temperature and standard pressure to see if it could release enough energy to heat the air by much. Who wants to do this calculation for me?
Why is anything anything?
Wich happends to be Avogadros number times the Boltzman constant (so it should be easy to remember off-hand...). Just FYI.
But it is difficult to remember all those old farts the constants are named after.
This is my sig, show me yours
Anyvbody with some industry knowledge care to comment on the chances of the prices coming down? This material sounds like it would be phenomonal to help with insulation in industrial and domestic applications, do a world of good to sort out global warming. The byline about a candle heating a house seems a bit of hyperbole but if it's even in the same ballpark as this then imagine the savings people would make on heating / air conditioning.
Realistically, is it likely to become affordable? like teflon went from space product to saucepans? or is it like space travel (by the 1970s we'll all be travelling to the moon on our holidays for no more than the price of a holiday in Florida...)?
I want a few sheets of this for my deer blind.
"Because of its ability to keep electronics on both the 1997 Mars Pathfinder and the current rover, Spirit, at room temperature in the face of minus-100-degree cold, aerogel will probably remain the insulator of choice on Mars missions for some time, Dr. Tsuyuki said."
Doesn't that mean aerogel could also insulate a Venus lander from the heat on its surface?
Sindri Traustason.
IR-invisibility cloak. Just wear it and be hidden from all IR eyes in the sky... neat.
I'd like to see a 15 gram balsa wood brick suspend that weight.
Rakshasa
In Europe a number of passively heated houses have been built during the last decade. In DK about 100 houses are to be built that will require the equivalent of about 625 KWh of electrical energy to heat them for a whole year. This is for a rather cold climate. Most of the heat is from the sun; ie, the sun shines on the house, warms it up (through window panes, etc)
These houses use about 300 mm of rock wool insulation (600 mm in the roof) and have heat exchanger systems that heat the water you bathe in from the heat in the house, etc.
I am currently building a totally normal house (with active heating) - it will require about 6-8 times as much energy in a year, but this is still a lot less than houses build 10-20 years ago. We pay a lot for energy over here - I guess that helps motivate saving it.
Mads Bondo Dydensborg
Too much math...losing interest...boring lecture...
;p
"Though it would be very expensive, you could take a two- or three-bedroom house, insulate it with aerogel, and you could heat the house with a candle. But eventually the house would become too hot.'" but it sure would make for a neat arctic government base.
Hrrm... I usually just sign my name.
Not as effective, but still uses aerogel
p ro ductID=115
http://www.burton.com/Burton/gear/products.asp?
"Aerogel": A Ridiculous Liberal Myth
It amazes me that so many allegedly "educated" people have fallen so quickly and so hard for a fraudulent fabrication of such laughable proportions. The very idea that a solid material happens to be so light, showing remarkable properties like near-perfect insulation, is ludicrous. Furthermore, it is an insult to common sense and a damnable affront to intellectual honesty and integrity. That people actually believe it is evidence that the liberals have wrested the last vestiges of control of our public school system from decent, God-fearing Americans.
I could care less, but not without a lobotomy
Could aerogel be formed with some other gas other than air, like pure hydrogen? Would it become lighter than air then and float around?
Just a thought, maybe some slashdotter knows, I've read the aerogel facts from the JPL page but it doesn't mention anything about this.
~~~Please pass the salt, I hate unsalted MD5s
I though slashdot was inane, but look at this
I've been wondering for a long time whether it would be feasible to create any kind of liquid that is lighter than a gas. Imagine a room where blobs of fluid are floating around (just like in zero-g), while all other physical properties are at their "normal" states.
This would also simplify cpu cooling a lot - just immerse your cpu in the liquid (it would have to be perfectly fine-tuned to be just heavier than air at room temperature) and a small fountain would appear over the hot areas below.
Certainly a stylish way to cool your cpu, but I suspect the laws of physics prevent such a substance.
Who knows what researchers come up with next.
"In this house we obey the laws of therodynamics!"
My Photography - http://ian-x.com
The Deathlings (comic) - http://thedeathlings.com
I've found a "Silica aerogel photo gallery"
http://eande.lbl.gov/ECS/aerogels/saphoto.htm
Some of the pics are really amazing. Cool stuff!!!
~~~Please pass the salt, I hate unsalted MD5s
I'd have been unable to resist doing the blowtorch-against-the-hand trick.
Funny, I thought the trick somehow involved Aerogel too.
Aerogel is also used within particle physics for telling different types of particles apart in Cherenkov detectors.
In any transparent material particles will emit light in a cone around their trajectory when they are travelling faster than the speed of light in that material (analogous to sonic boom produced by plane going faster than speed of sound). From measuring the angle the light is emitted at we can work out the velocity. The range of velocities we are sensitive to depends on the refractive index of the material which is where aerogel comes into the game. We have gasses with refractive indices very close to one (n = 1.0005 for CF4) or glass with large refractive index (n=1.47 for quartz) but no normal material in between. Aerogel with a refractive index around 1.03 gives us new possibilities.
Within a particle physics experiment we can use a magnetic field to determine the momentum of a particle from the curvature of its trajectory. If we put this together with the measurement of its velocity from the Cherenkov detector we can work out the mass. This allows us to distinguish pions and kaons in an experiment like LHCb which is currently under construction. Here CF4 (gas), C4F10 (heavier gas) and aerogel are used to give coverage of a wide velocity range.
Aspen Aerogels has some Aerogel products on the market today. I've seen the stuff in action (about 1/10 inch worth protecting someone's hand from an acetylene torch), and it's amazing stuff.
"""
When you heat up a house, you run air into a furnace, heat it up, and then pump it through the rest of the house.
"""
No I don't. I heat water, and pump that round the house.
Look up "radiator" in a dictionary some time.
YAW.
Your head of state is a corrupt weasel, I hope you're happy.
Great for hemorrhoids
The only problem with Areogel is that is really expensive.
.16 as good an insulator as Aerogel but it is basically free. I guess it's also edible. This might be a better option for insulating your house, although you might have to dope it with some preservatives.
One solution is Seagel or Safe Emulsion Agar-gel. You get old fashion agar (the stuff that flows off the teeth of the Aliens.) The resulting foam is about
Sounds totally worthless to me. This stuff will probably end up having no practical value anywhere. That being said, anybody know where I can buy a small block?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item =3654360332&category=416
I saw this stuff on The Next Step or Beyond 2000 years ago... I think they called it "Frozen Smoke" at the time... Amazing stuff... I think they said a piece the size of a sofa would weigh about as much as a loaf of bread... Cool to see it again with a real use... Did anyone else see it back then?
For several years at Disneyland, they've had a sample of it in FutureLand or TomorrowLand or whatever it's called. Sort of across the path from Star Tours, there is a whole exhibit about the US Space Program. Inside a glass case, they have a square of Aerogel held up. Unfortunately, they don't let you touch it or anything. But it is interesting to look at - it's hard to find the edges of the material, even when you are concentrating.
-If
Run a pencil-and-paper RPG campaign with your far-off friends: Gametable!
Ok, so if aerogel has the lowest density of any solid, what has the highest density?
Right now I'm thinking that it's either corporate America's CxO's, or perhaps whoever keeps watching all of these dumbass reality shows on tv.
You forgot to mention the reason for using Aerogels as Cherenkov detectors: they present very little mass, so low-mass particles will not interact and/or deposit much energy in them (e.g., for electrons the Aerogel will act only as a Cherenkov detector and not a calorimeter). The only other real alternative for getting indices of refraction barely over 1.0 is to use pressurized gases, which present a whole series of their own problems.
Welcome to gravity, its pretty much the same for everybody on earth.
The issue isn't gravity, but air resistance. A feather doesn't fall as fast as a bowling ball in air. Since this stuff is fairly light, one would expect air resistance to slow it considerably.
In Ukraine (Russian border area, at least) they put mayonaisse on pizza and look at you funny if you ask to have your pizza made without it. (Of course, you don't know to ask to have it left off unless you've been there before...)
Secession is the right of all sentient beings.
Diatomaceous earth is 100% natural microscopic glass shards. Being microscopic glass shards they are an excellent insecticide. The shards pierce the insect's shell and through capilarry action, they suck out all the internal fluids drying the bug to a corpse. However, the shards are so small that humans can ingest them without fear of harm.
So if you have a garden, or some veggies or other food you want to protect from insect pests without using a substance toxic to humans and pets, sprinkle on a little diatomaceous earth. Better yet mix up some garlic powder, water and diatomaceous earth in a bottle and spray it on. Garlic kills bugz too w/o being dangerous for ppl.
Eat at Joe's.
Most of the properties of aerogel can be found in other substances. Aerogel isn't special because any one of it's properties is unique, but because it has several useful properties in one substance/
This means that you can theoretically heat or cool a house with just a painted square on the roof a few square meters in area, if you could just create a material of the right color.
:-)
Ummmmm... I'm afraid that at least with respect to heating, it's been done: glass is transparent in visible light but opaque at room-temperature black body radiation frequencies, aka infrared. It's called the greenhouse effect, and it heats my wintergarden just fine.
Another great patent idea lost to public-domain prior art - doh!
- nic
Be faithful to your obsessions. Identify them and be faithful to them, let them guide you like a sleepwalker. JG Ballard
I have a question for the physicist. How much excess heat is generated in the average daily rountine of an American house person including all home applicances?
I don't think the candle would be required at all. Just put in a human or some thing is that is alive, or some applicances and that should be more than enough heat. I don't have any numbers to back that up. I just figure that if we can use clothes and quilts to stay warm. Then if our home had near perfect insulation, then all it would take would be me to heat it up. I agree that there would need to be some way to move excess heat out though. I know laying down on the couch covered in a quilt can get quite hot, and feels alot better when colder fresher room area is circulated under it.
so what exactly is a "cubic centimeter for one liter."
[Fuck Beta]
o0t!
Well see, with air between panes, theres convection, which reduces efficiency. A vacum eliminates convection, but allows energy to pass.
Aerogel would both stop convection and (much) energy transfer, but there's no way it'd be transparent enough for windows.
Campaign finance reform is national security.
Assuming you have the right autoclave. Go here for some recepies.
Drinking habits can be dangerous. You can choke on the cloth and the nuns will wonder where their clothes are.
This is what I wanted to know, thanks.
No doubt a respirator is advisable. There's a lung condition from exposure to concrete powder (silica), which is nearly as bad as asbestiosis.
Campaign finance reform is national security.
They once passed a chunk of aerogel around in one of my graduate physics classes. One of the interesting visual effects of the stuff is that, since it is mostly air, it has the same index of refraction as air and does not bend the light like a piece of glass or plastic or any other transparent solid object that you are familiar with. It is a ghostly object in your hand.
Religion is poison to rationality, and we lose sight of that at our own peril. -- Lurker2288
But that's precisely why home insulation, no matter how much you put in it, is essentially worthless.
Here's an article to shed some light on that.
To summarize, insulation can be completely defeated if the building isn't airtight.
.sigs are for post^Hers.
Flubber
Intelligence is like four wheel drive, having it just means you'll get stuck in more remote places.
You mean like one of these: http://www.smarthome.com/3033.html
... Browsing.
I need to make a cast for a transparent object, which will be two plates of glass, seperated by some kind of spacer. I thought maybe window screen spline would work, if I could find it in square cross-section or concave. So went to Lowes hardware and no, only round and ribbed in 20 flavors. Not good for a flat object's edge.
Wandered around the store for an hour or so, looking for anything that might work. Yeah, it took time, and I was impatient, but I've gotten some great ideas before this way. I came across string trimmer line which is actually square in cross-section, comes in various sizes, and has a polished finish! Perfect.
Tame your inner beast, and make discoveries.
Campaign finance reform is national security.
Take a look at the aerogel picture again:
here
What's up with that shit? Is it a man or a woman??? Long fingernails, but hairy like crazy!!!
Is there anywhere to actually buy this stuff without a multimillion dollar contract? I'd like to have even a couple dozen cm^3 of this stuff just 'cuz, but the only sites I can find talk about industrial uses, etc. What about the novelty market? Lots of people (me) spend money on crap just because it looks cool, and this is a great item for that market.
Basically, where can I order it in small quantities?
Here is a picture of wires in aerogels.
http://mrmac.mr.aps.anl.gov/~jterry/nano.html
I'm concerned about the assertion that the Sun radiates in a narrow band. It has a very broad band of emission.
If he's talking about just the infrared, maybe there is a narrow band that's most efficient for conversion, but the other freqs will prevent the cooling effect.
Some bona-fide original thinking though.
The best idea I've seen here is tubes under the house underground, to 'normalize' the outside air. Take advantage of the Earth's heat sink, AND have fresh air all the time. (unless you're in Houston) I guess they'd have to be buried 6' down, and be spread out over twice the area of the house footprint, ideally under the house to conserve its moderate temp.
Campaign finance reform is national security.
They make several claims for the density of aerogel. One is 3 times the density of air, which would be 3 to 4 mg/cc. Another is 1/100th the density of a hand, which would be 10 mg/cc. Granted that it can be made in various densities, but come on guys, be consistent!
Contribute to civilization: ari.aynrand.org/donate
can take 3 times it's weight, but not without a hiss...
NEOCA - Custom LED Flashlights
Even tho I have no need for the stuff, I recently bought a piece just because I thought it was cool.
p li ers.html
I got a ~2 in3 piece for $100. I got it from the Star Gazer's Gift Shop, but the following link has a couple of sources...
http://p25ext.lanl.gov/~hubert/aerogel/agel_sup
Don't even need special clothing to hide from satellite. Aerogel Sombrero!
Campaign finance reform is national security.
See subject.
You get sun for a smaller part of the day, but at very close to the same intensity.
However, you can do the math -- small changes in incident sunlight would make fairly big changes in temperature.
That would be VISIBLE light. The Sun emits a lot of visible light. If I'm not mistaken, that is the part of the spectrum where the Sun radiates a lot. Go down to IR. Now go a bit deeper, into deep IR. There, you're starting to get black body radiation from Earth, and not as much from the Sun. Hot things go up in frequency (compare a blue torch to a yellow torch flame).
I've read so many articles, and even recipes on how to make aerogels, but have yet to hold, touch, or even see one. Is there any museum (brooklyn science, liberty science, etc.) that would have a sample, or any body know of any other ideas?
-Christopher Wu
http://www.christopherwu.net/
Aerogel is cool stuff. I've recently been experimenting with aerogel capacitors. These suckers can hold a huge amount of energy. Right in front of me I have two 2.5V 50-farad (yes farads, not microfarads) capacitors.
Fun for robotic projects and such. Many common devices are using super-capacitors like these. Those tiny remote control cars and those battery-free flashlights are a couple examples.
The ratio of people to cake is too big
I used to build balsa wood structures that would hold over 600 lbs(~270kg), with only 15 grams of balsa wood and glue, with strict rules on how it could be built.
Olympics/Odyssey of the Mind? You GEEK! Neener, neener! (Oops, know I have to explain how I know about it...)
Downmodding is the refuge of the weak. Don't downmod, make a better argument!
Maybe that's the other AeroGel.
One bad monkey spoils the whole barrel.
Has anyone thought about how damn long it would take, with all the furniture, appliances, cabinets, water, etc... that sunk heat? Maybe this candle we're talking about doesn't run out of wick during the time it would take to heat up the house. ;-)
Don't mind me, it was -25C the other week. If only the house was insulated year-round with areogel, my body heat would be enough to keep it warm.
You can already get windows (and transparent walls) from Kalwall that provide up to R-20 insulation. They use a form of aerogel called Nanogel , which is manufactured in Germany by Cabot (not like the cheese). The granular aerogel is packed between two translucent panes to form a structural panel.
The newsletter I work for wrote an article about it a couple of years ago. The article explains the insulation properties this way:
Some other fun facts:If you follow the link in the post, you will see actual black body radiation frequency curves for several frequencies, from which you can extrapolate that what I say is true. Alternatively, they give a formula for Planck's Law, with which you can plot the curves (apt-get install octave), and confirm this. If the Sun were a black body (which it's not, but that actually works to our advantage here), at 5000K (the surface is actually a bit hotter; I'm using very conservative numbers to prove this point), its radiation would peak at about 0.58 microns wavelength (yellow). At 300K (a warm day), the black body radiation of Earth peaks at 9.7 microns. By the time you hit 9.7 microns, the Sun still radiates, but it is at 1/3173, or less than 0.03% of what it radiates at the peak. This is pretty negligable. In reverse, the Earth radiates over 27 orders of manitude less at yellow than it does in deep IR where its radiation curve peaks.
This lets you play the game with heating/cooling described. You're taking advantage that you have two curves, one of incident light, one of radiated, of roughly equal intensity (the Sun shines for a little less than half the day, which is why the 300-500W radiated figure is just under half of the 1000W incident figure), but of very different distributions. The Sun has a much hotter distribution, but is reduced by the distance to the Earth.
The Sun does radiate SOMETHING at every frequency. It's just that it doesn't radiate very much beyond its peak.
Neutrinos are particles, not light. The Sun radiates just about everything, if you wanna measure little enough of it. It peaks at yellow, though, and doesn't give off a heck of a lot beyond that.
yeah! what he said! put that in your pipe and smoke it!
If you have a useful point, make it, rather than insulting the qualifications of someone whose qualifications you do not know.
The person who showed this to me was well aware of the subtleties. He did work out the math for this, taking into account the radiation curves of the actual sky (air, occasional clouds, etc) -- it worked just fine -- I just have neither the space to post it on Slashdot, nor the time to work it out again.
If you're concerned about other heat transfer modes, we do have the material science to insulate from those very easily, without losing the properites of this one.
If you have anything clueful to say, please do so. Otherwise, quit trolling with the insults.
Fucking clueless, yet sarcastically superior, morons.
Aerogel coffee mug.
"I'm just here to regulate funkiness."
Just curious, what is the difference between your idea and an existing heat exchanger? They work in a similar fashion.
Make the aerogel with hydrogen or helium instead of air, then build a city on it. Might as well use hydrogen, because if an airplane runs into your solid cloud, fire hazard is the least of your worries. There is probably a way to separate aerogel regions so that an accident that shatters or burns one region doesn't spread to other regions.
From the article
Not only does the paste stop heat from getting through, it cools to the touch within 20 seconds of the fire source being removed.
When dry, the paste is non-toxic four times lighter than aluminum, more heat resistant than titanium, and costs only pennies to make
OK, so how exactly did this get modded to "-1 Informative"? This deserves a +5. So what if it was from an old discussion. It's interesting, informative, and includes a link to the source material. Keep your ego out of moderation. It's not a fucking karma contest. The poster made a good post, so don't mod it down. Fucking idiots.
So...
I'm a bit confused as to what they are measuring, when they say it is the least dense: is it the total volume of the cube divided by the mass, or merely the volume of the gel matrix within the cube?
If it is the former, it would seem to be easy to make a less dense solid: make a big cube of aluminium foil. Since the volume rises as the cube of the side length, but the surface area, and hence mass, rises as the square, you can give it an arbitrarily low density.
Except that diatoms are awfully bad for your lungs. Handling diatomaceous earth directly can dislodge thousands of little diatom skeletons into the air, which you then inhale. The effect on your lungs is not unlike that of asbestos.
Reference: I used to work in a lab that analyzed air and soil samples for asbestos, and one of the main things we also checked for were diatoms. (on the advice of the resident pulmonary toxicologist)
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In the 70s Dr. Harold Orr, Division Of building Research of the National Research Council of Saskatoon, designed a "zero" energy house for the climate of Saskatchewan.
A family of 4 would, just by living (cooking etc) heat the house. I do not believe that the enegy for heating the bath water was included
The specific heat of air is rather high. It'll store the air for a while, there, high speed. Go back to thermodynamics and try again. It'll stay warm. That's what insulation does.
The specific heat of air is rather high. It'll store the /heat/ (heh, my bad) for a while, there, high speed. Go back to thermodynamics and try again. It'll stay warm. That's what insulation does.
And, umm, yes, I already pointed out that the cracks allow for an equilibrium state with regards to pressure. Hot particles escape through the crack, but there are still hot particles left in the house, and we now have a pressure equilibrium between outside and inside, while the temperature remains high. There is no net gas flow, at this point of temperature inequlibrium, as the pressure's are the same. Over time, diffusion back and forth through the crack will even out the temperature, and interaction at that boundary will cause conductive transfer. But the fact that the air in the house is holding the heat is a very important point that you're seeming to miss.
Tm
Support TBI Research: http://www.raisinhope.org
One of my classmates in high school science research class worked on a project with aerogel. The stuff has been around for over a decade.
White actually works much better than foil -- white reflects more light, even if it scatters it. Foil (and mirrors) reflect it in a straight line, so you see a reflection, but they reflect less of it. The other (rather critical) thing is finding something that reflects deep IR, rather than visible light. You can't see that with your eye. You also don't want a tube -- a tube has a large are covered with foil, and a small area exposed to the sky. If the foil is at all imperfect, that will multiply it quite a bit. You also need the thermometer to be well insulated from anything other than radiation -- if you just stick it in a top, airflow will cool it quite a bit. Ideally, you'd use a series of transparent boxes to shield it from other methods of gaining/losing heat. The problem with doing this experiment is it needs to be very carefully set up -- it's not an easy problem.
I once tried to make a homemade electrolytic capacitor out of aluminum foil and vinigar when I was in high school. The acid in the vinigar ought to form a layer of oxide on the foil. Both vinigar and aluminum conduct. The basic idea is fine -- you've got electrolytic capacitors all over the place. The only problem was with my implementation -- the oxide presumably had holes in it do to impurities, so the vinigar and aluminum shorted, and I got a nice conductor instead. But the fact that a half-assed experiment doesn't work does not imply that the basic idea is flawed if it were to be properly engineered.
The sky is mostly transparent, until you get into the very high frequencies (gamma rays, etc.), and it doesn't actually radiate or absorb a heck of a lot. According to one web site, the atmosphere absorbs 17% of incoming radiation (including clouds), and reflects 31% (7% clouds, 24% scattering). Reflection doesn't change the calculation (if I'm not mistaken, the kilowatt figure given in the original post was at the Earth's surface, not in the atmosphere). 17% absorbtion/black body radiation will make a difference, but only a 17% difference. The original idea still works.
Ummmm... something is wrong here. if n changes, then something is leaking out.
some definitions...
P V =n Ru T is commonly called the "State Equation"
P is pressure,
V is volume
n is the number of moles of gas in the volume
Ru is the universal gas constant
T is temperature
In this example, the volume is constant. also the number of moles is constant (if nothing is leaking out, then the number of moles is constant). then any increase in T results in a corresponding increase in P. If T increases and P doesn't, then either V or n isn't constant.
an alternate form of this equation is
P =_rho_ R T
where _rho_ is the density and R =Ru/Molecular weight of the gas. If the house is air-tight, density is by definition constant. then T and P vary directly. If T and P do not change at the same rate, then the density MUST be changing.
I don't follow the logic behind why this has anything to do with heating the house? If the house is airtight, when T goes up then P goes up. If the walls are of sufficient strenght to support the pressure differential, then there's not a problem.
If the house isn't airtight, then let's assume P is constant, if the temperature increases, the density must decrease accordingly (that is, air will leave the house). When the temperature falls (due to poor insulation), then the density must rise and air from outside will be sucked in.
And yes, i am a thermodynamicist...
They also have several samples on display in the Tech Museum in San Jose, CA. Also under glass, but you can get very close to it and see how different it looks as you move around and view it from different angles.
"Those who have never entered upon scientific pursuits know not a tithe of the poetry by which they are surrounded."
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> Though it would be very expensive, you could
> take a two- or three-bedroom house, insulate it
> with aerogel, and you could heat the house with
> a candle. But eventually the house would become
> too hot.'"
I hope Aerogel is not as dangerous as UFFI !
They're completely unscientific.
Of course I oppose aerogel too, but only because I know that NASA is part of the military industrial complex.
Plus, they say it's "inorganic", and we all know that if it's not Organic, it's Bad. If conservatives weren't such religious fanatics and read a few scientific studies, like they have in Mother Jones, they'd see that.
[sigh...] Oh, well. Now where are my crystals. Gotta get rid of this negative energy so when I'm running the School Board meeting tonight all those neanderthal conservatives who often show up won't uncenter my chi....
"Those who have never entered upon scientific pursuits know not a tithe of the poetry by which they are surrounded."
on this note - whenever my brother and I would open the front door when the air conditioning was on in the summer, my Dad would immediately start counting (loudly) the money we were wasting while standing there talking to our friend who had stopped by... "One dollar! Two dollars! Three..."
Intelligent Design: because MATH is HARD.
Actually it's not a good illustrative statement, it's pretty crappy.
1. The candle would be entirely unnecessary: body heat would do just fine.
2. In some "physicsland" example where people don't need to breathe and completely restricting airflow in and out of the house is okay, the aerojel is pretty serious overkill. More conventional stuff would do just fine.
So how is the statement illustrative in a useful way?
Now before I get modded down, I be to remind whoever might read this that what I am saying is FACT. - bogaboga
In the article on lbl.gov about "How Do You Work With Silica Aerogel Without Breaking It?" they state Nevertheless, it is a good precaution to work in a fume hood ...
Wouldn't aerogel be sucked up by the hood if it is nearly as light as air ?
I have a buddy that is looking into aerogel as a Hydrogen storage medium for fuel cells.
In reality the aerogel described is only one of many possibilities. This one is silica. You could form aerogels out of many different material or with different "contaminates" that could give it a variety of different physical and/or chemical properties. It's very cool stuff.
And on the density angle, who is the dumbass talking about the aluminum cube? A solid is a continuous phase of one material. An empty cube of aluminum foil isn't a solid, it's an cube full of air. Besides, you could stand on the one, or use it as a material. Build a cube out of aerogel slabs, that will be even less mass than your magic aluminum box....
near frictionless and super-insulated. of course, a certain amount of friction is desirous, but that would build up heat, it wouldn't dissipate, ouch.
Why isn't this being used for the space shuttle instead of the foam? Is the foam better or am I missing something?
As forkboy said, diatomaceous earth is horrible for your lungs. It's used in some commercial pool filters, since it filters out all sorts of yucky stuff you wouldn't want in your pool.
The only thing is you need to replace the DE every so often (at least 4-6 days at the pools where I worked), otherwise it would filter too well and not allow water through. Replacing it involved pouring 20-lb bags of DE over the filters. Particulate mask most definitely required.
Also, I knew some old-school employees of the pools who got 'white lung,' similar to coal miners getting black lung, from breathing in DE. Back then they didn't know it was so harmful.
What to do in the summer? That's the crux of the whole idea. This is heating AND cooling. In the summer, you cover the roof with something that reflects visible, but is a black body to deep IR. It picks up very little heat from the Sun, but radiates a lot of heat out into space. The roof cools the house. I have no idea where to find such a material, but if found, the house would cool itself every bit as efficently as a greenhouse warms itself in the winter.
The only obnoxious thing is swapping/rotating panels between winter and summer.
The favorite of cheapass architects everywhere who can't stand to stop and sharpen their leads once in a while. Leavs a crisp line, but it's so faint that it's damn near impossible to run a diazo print off it.
My other car is a 1984 Nark Avenger.
Garlic is useful in another, simpler (and tastier) way. Just plant one clove of garlic every few feet of garden, and most insects will avoid your garden. They're not the most aesthetically pleasing plants (they look like any other bulb plant minus the pretty flowers) but they aren't offensive either. This requires no special maintenance beyond what you'd be putting into the garden anyhow, and as a nice side benefit you will find an entire bulb of garlic underground come harvest time.
Also falling into the non-hazardous pest control category would be cola bottles with something still at the bottom (insects drop in to eat, can't fly back out), and leaving shallow containers filled with beer around for slugs and snails to climb into. Then they get drunk and drown.
I believe it is diatomaceous earth that is at the hear of the "ant chalk" you can buy at the local 99 cent store. If not, it's probably borax, which as far as I know operates by the same means.
Mal-2
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
Does any one now what that chalk is? I'm not able to read the box, as I don't speak Chinese, so I've just called it "Chinese Death Chalk". It really kills the hell out of the ants, and they don't cross the chalk line for a few months. Really, it's the best thing I've found for controlling ants.
I heard the gov't busts vendors every once in a while for selling it. I've just wondered what's it made of and if there are any long term consequences from using it. Does any one know?
"Eye halve a spelling chequer, It came with my pea sea, It plainly marques four my revue, Miss steaks eye kin knot sea"
ant chalk or "Chinese Chalk" is a nasty incesticide that is illegal in the US. May include deltamethrin (neurotoxic in mammals -death by seizures) but no one is really sure. Definately not diatomaceous earth, borax, or aerogel. Don't use it, especially if you have kids or pets.
6 A. html
http://www.pestlaw.com/x/press/2003/NYS-2003121
We do have such a black body -- space. That's the entire point.
The Sun is a black body at about 5600K (give or take a few hundred). However, the Earth is very far from the Sun and it makes up only a small part of the day sky (about half a degree). The rest of space is a black body at about 2.7K. The overall sky, as viewed from Earth, would have the radiation intensity of, very crudely, on the order of a black body at 600K during the day and 3K during the night, and 300K integrated over the course of 24 hours (ballpark figure -- the 600K may be off by a hundred one way or the other).
But while the intensity is that, the frequency distribution of that incident radiation is not that of a 600k black body during the day. It's the sum of the frequency distribution of the Sun (a 5600K black body), at greatly reduced magnitude, and of space (almost entirely dominated by the former). This is what lets us play the tricks. The radiation intensity of the sky, with or without the Sun, in deep IR, is very, very low. A 5600K black body radiates mostly in the visible light range, centered around yellow. The radiation level at deep IR is fairly small. Although it's obviously higher than for a 300K black body at the surface of the Sun, by the time you scale it down for only occupying 30 arcseconds of the sky, it becomes pretty negligable.
We don't violate thermodynamics. We're not warming the Sun -- we're reflecting it, and so ignoring it. We don't warm it, it doesn't warm us, and we're a white body. We are, however, warming the rest of space. It's at 2.7K, so we gladly take on its radiation, and radiate to it in turn.
We also don't have the T^4 problem, since while the surface of the Sun is at 5,600K, it's a small part of the sky, and we're only seeing about 600K worth of radiation from that when we look at the entire sky. Either way, it's a delta T of 300K.
One other thing. Read the post "Not True, Very Narrow Frequency", and possibly the link on black body radiation in the original post. Those will explain/give math behind why the filtering actually works.
How about AeroGel as a component of gas masks?
Found a useful looking list at Aerogel Suppliers. Nothing in Canada listed, unfortunately...
The main site though, Hubert's aerogel page, seems to have an interesting collection of links on Aerogels.
Another NASA invention that wasn't invented by NASA. After all is said and done, it's just Tang
-------- -------- Support Wesley Clark for president!!!
And on the density angle, who is the dumbass talking about the aluminum cube? A solid is a continuous phase of one material.
Well depending on the resolution you want, that's at best a short hand approximation, at worst patently ridiculous.
Most aluminum solids I'm aware of tend to the polycrystaline side of things. But I'll just throw out ice cubes, and steel anyway.
or the other part of that is it converts some forms of radiation in to light, does that mean if you made a big Sphere of the stuff it would be well lit and warm on the inside.
Prolly not. Since aerogel is so low density, only a tiny fraction of the particles passing through create light. To get enough light to usefully illuminate the region underneath you'ld most likely need a layer of aerogel hundreds of meters thick.
But in that case, since it is not one hundred percent transparent (if it were, it would be invisible), you'ld lose more light from transmission loss then you'ld gain from all that volume.
Feel free to do the math, but I wouldn't keep my hopes up.
Rustin
Data is the lever, rigor the fulcrum, brains the force that drives it all.
That's no brick! That's a red monolith!
Hmm... I like it. Maybe you should enter my competition. Or at least do a more detailed JE on it.
Rustin
Data is the lever, rigor the fulcrum, brains the force that drives it all.
It's used in residential pool filters too. Our pool has a screen filter which won't do anything without it. Has to be flushed and replenished every few months.
Nothing to see here; Move along.
Run-around heat exchangers are nothing new, and energy recovery ventilators have been around a while, too. My point is, there's still no way a house with adequate ventilation for human occupancy, even just one person, could be heated with a single candle.
Um, did you miss the part about how new air is being blown into the house and stale air being blown out? I didn't specify sizes, so it is safe to assume that the ventilation system would be sized properly. A baffle system allows you to turn off the fans when the air is fresh enough. Presumably, the baffles would be coated with aerogel for insulation as well. It's a solution to your problem.
And you're right, basic refrigeration has been around for awhile. :) Your point is that a habitable house with adequate ventilation can't be heated with a single candle, and I offered a solution. Whether my solution is new or decades old is irrelevant, because it's a solution.
Here's the problem in a little more detail:
To provide adequate ventilation, you have to pump out old air and pump in new air. Well, it doesn't have to be pumped at all, but that's not the point. The point is you have to have old air removed and new air added. When you do this, presumably you would bring in cold air, since you wouldn't be heating the house if the outside air wasn't cold. And you'd have to vent hot air. So, the solution is to remove the heat from outgoing air and insert it into incoming air, keeping the heat within the house and never letting any of it spill out.
This is a problem solved by basic refrigeration. In your refrigerator, your air conditioner, and a number of other gadgets, you put the heat inside the house into the freon, pump it outside, and dump it. In the case of your refrigerator, you're just dumping the heat into the kitchen and removing it from inside the box. I described a system that uses those same basic components to keep heat inside a box rather than remove it, that's all.
Like what I said? You might like my music
See replies to the other posts for exact numbers, and the math behind them.
To summarize the effects of the sky: The atmosphere absorbs 17% of radiation passing through it (this is taking into account clouds), and the amount it radiates is proportional to that. This is a noticable, but not deadly, hit to efficiency. It scatters considerably more (around 24%, which is why the sky looks blue -- the Sun's light beying scattered -- the atmosphere generates very little radiation, and it's all in the deep IR -- if the sky was radiating blue, you would see it at night as well), although the way scattering works out, it doesn't effect the efficiency very much at all (and the numbers I gave for incident radiation from the Sun were taking this into account).
In terms of Sun's IR swamping anything, this is definitely not true. The Sun's black body radiation peaks at 0.58 microns (yellow); the Earth's, at 9.7. By Planck's Law, by the time the Sun gets down up to 9.7 microns, it's down to under 0.03% of the radiation it radiates at yellow -- this is a negligable amount by the time you hit Earth (the sky only occupies only a tiny fraction of the day sky -- IIRC, it's about half a degree. Since this is from a 2d plane, it's a very, very small amount). The numbers in reverse are even more extreme -- the Earth's black-body radiation is down 27 orders of magnitude (!!!) by the time you hit yellow.
If I'm not mistaken, you can actually prove that the amount of greenhouse heating you can achieve is equal to the amount reverse-greenhouse cooling you can achieve, given that the Earth is in thermal equilibrium, and assuming that the Earth absorbs roughly equally across the frequency range. I do not know how correct the second assumption is, but if you work through the math, it is easy to show that the cooling is significant. In an ideal world, you could cool a house with just a few square meters on the roof. In the real world, you might need more, but the entire roof ought to be much more than adequate.
In terms hot asphalt and so on, this is a detriment to any method of air conditioning -- not just this one. The cooling element is positioned on the roof, which only sees the sky (except for scattering). It's just, as with normal AC, a matter of how well you insulate the walls. What matters is how many watts of heat you're losing. Here, it's about 500W/square meter ideal, and maybe half, worst-case-scenerio, a quarter of that real. My window AC unit burns about a kilowatt, but by the Carnot cycle, can't be too efficent, and in practice, is very inefficient. It also only needs about 50% duty cycle. If the entire roof over my ceiling was covered with this stuff, it'd be sucking a lot more heat than that, and my room would be very, very cold.
Also a disclaimer. I'm not claiming this is economically viable. Deep IR filters exist, but cost an arm and a leg, and aren't designed to hold up under years of weather. I also don't know how good they are -- you'd need a pretty good filter for this to work (comparable to what glass does, but in reverse). I also didn't invent this -- it was shown to me by a rather clever professor. I just think it's a neat hack.
Just as irrigation is the lifeblood of the Southwest, lifeblood is the soup of cannibals. -- Jack Handy
There is nothing fantastic about the "faster than speed of light here". The speed of light is lower than in vacuum in all materials. As an example in quartz the speed of light is around 200000 km/s compared to the speed of light in vacuum which is 300000 km/s. So a particle travelling at 290000 km/s travels faster than the speed of light in quartz (and thus emits cherenkov radiation) but slower than the speed of light in vacuum.
Einsteins theory of special relativity says that particles cannot travel faster than the speed of light in vacuum so no "warp" factors are required here.