Can we construct a solid material that will float in air?

[plutocrass]

Hi to all:<br /><br />I read this page at livermore laboratories,<br /><font color="yellow"><br />Livermore is internationally recognized for synthesizing extremely low-density materials with specialized composition. In the past year, we produced a solid-phase sample of silica with the lowest density (1 mg/cm3) ever made for a solid (Figure 2). The production of this sample required the use of newly developed, rapid supercritical extraction processes. The ability to synthesize such materials assists Laboratory programs in materials performance, warm-dense matter, and high-energy-density physics. Recent examples of applications are an iodine-doped polystyrene material to be used as a heat pre-shield in laser-driven experiments on the Omega and NIF lasers and novel metal-doped nanocellular materials for NIF targets.<br /><br />We have continued to explore the production of aerogel materials for new elements in the periodic table. Production of aerogels of urania (UO3) and thoria (ThO2) provide materials of importance to Livermore programs and also provide unique insights into the potential and limits of synthetic chemistry at extreme low densities. As an example, the urania aerogels have densities in the range of 0.1 to 0.2 g/cm3 and physical features in the size range from 5 to 20 nanometers.<br /></font><br />Ultra-Low-Density Aerogels <br /><br />

 

[newtonian]

josh1943 - Thank you for the relative weight per volume of typical aerogel and air and CO2. <br /><br />I agree it seems that lighter gasses (helium, hydrogen) could be used - helium is, of course, inert. <br /><br />However, as silica (SiO2) is also fairly inactive (almost inert) and is the main ingredient in aerogel (and also glass, incl. glass foams, etc.) - I would think the highly reactive hydrogen could be contained within a silical base with no problem.<br /><br />The preheating manufacture could be a problem though!

 

[newtonian]

plutocrass - Thank you.<br /><br />However, we need the comparison with air!<br /><br />The lowest density silica (aerogel?) is 1 mg/cm3.<br /><br />The density of air is _______ mg/cm3.<br /><br />Is there an easy way to look up the density of air in this unit?

 

[fingle]

the density of air at sea level and at 20 °C dry air has a density of approximately 1.2 kg/m3.<br /><br /><br />I'm not sure what you mean by "The density of air is _______ mg/cm3. " <br /><br />when you say cm3 do you mean centimeters cubed ? which is usally expressed as cc. <br /><br />if so that would make it 1200000 mg/ 1000000 ml.<br /><br /><br />or i totally misunderstand what is going on.<br />not unusual.<br /><br /><img src="/images/icons/smile.gif" /><br /> <br /><br />edited to say: that just doesn't look right to me aaaarrgh!<br /><img src="/images/icons/frown.gif" /> <div class="Discussion_UserSignature"> </div>

 

[newtonian]

fingle - Hi!<br /><br />Thank you. <br /><br />OK, 1.2 kg per m3, i.e. 1.2 kilograms per cubic meter.<br /><br />mg/cm3 is, I think, milligrams per cubic centimeter - I need to convert this mathmatically. <br /><br />Now 1,200,000 mg/1,000,000 ml is, if I do not misunderstand, is per milliliter - that confuses the units further by using liters instead of cubic meters or cubic centimeters.<br /><br />My problem is that I do not remember all the conversion factors and would appreciate either a link or post showing how the varying units compare mathematically.<br /><br />For example, how many cubic centimeters in a milliliter?<br /><br />A tangent: obviously adding a light gas enclosed in a structure could make the structure lighter than air.<br /><br />Today on the Science channel there was an interesting program on Holland's technological efforts to adapt to rising sea levels, falling ground levels and below sea level land - and one adaptation is floating homes and floating cities. One model involved polystyrene (or a similar light material) enclosed in a basement plus being anchored to pilings with the ability to rise and fall with the change in water level.<br /><br />Obviously, the same principle would allow for homes and cities floating in air provided the enclosed gas or solid is lighter than air.<br /><br />Short of this, structures only slightly heavier than air could have multiple levels much greater than today's skyscrapers without the need to have fantasticly strong load bearing walls. The same need for anchoring (wind instead of water flow) would, of course, exist.<br /><br />Interestingly, lightweight materials are often good thermal insulators - see my surviving red giant phase thread.<br /><br />BTW - I do have a good imagination!

 

[fingle]

Hello Newtonian,<br /><br />I got the density of air numbers from wikipedia, and the conversion stuff from a site like this one, Online Conversion Volume conversion. and I don't know how I missed it before that cubic centimeters can be shown either as cc or cm3 like you had it. I knew I would get confused, sorry about that chief. <img src="/images/icons/frown.gif" /><br /><br />according to the conversion calculator 1 cm3 = 1 ml. <br /><br />As to airborne cities I recall some old discussions about geodesic domes, where the claim was made that a dome large enough to cover an area like new york city, would get some of it's support from the hot air captured inside. The dome would not actually be lighter than air but there would be less weight for the foundations to have to bear. that is after the dome was complete and the hot air was sufficiently trapped. Maybe replace the hot air with helium ?<br /><br /><img src="/images/icons/smile.gif" /> <br /><br />later than i thought.<br /> <div class="Discussion_UserSignature"> </div>

 

[ldyaidan]

Any info on how Aerogel is at blocking radiation? I'm just thinking that if it was able to do that, it would be a huge boon in spacecraft and habitats on the moon and Mars. Most of what I've seen calls for a lot of water to be used to help block radiation. If aerogel could do the job, as well as act as an insulator to keep the heat in, it would be a lot lighter, and possible require a much thinner layer than the several meters of water that would be required.<br /><br />Rae

 

[newtonian]

fingle - Thank you.<br /><br />Super busy, will respond later.

 

[spunisphun]

would anyone want a very very tiny sample of aerogel, i obtained a about 10x10x2 inch block about 6 years ago, and it has been crushed, pulverised, but there are still some chunks, and alot of powder. just private message me and maybe we can workout a deal, like for the shipping or somthing kuz im not in the mood to pay for somthing that im giving away, that i could easily sell on ebay.

 

[newtonian]

fingle - Yes, helium would certainly be better than air. And more stable too, I think - what with being inert!<br /><br />Have they tried a Helium infused aerogel?