Blue Smoke

Last summer my kids and I helped staff at Cub camp. I've been the camp director for both Catalina Council camps and Spanish Trails District camps, but this time I was just a staffer. It was out at the Pima Air and Space Museum.

After the day was over we got to go tour the facility. I've been there before, but not since they added things like my new favorite substance. My old favorite substance used to be Bucky Balls (It's still number two. I mean...those things are handy little critters).

But now they've got Blue Smoke, Frozen Smoke or Aerogel!

As I was looking at the displays, I noticed a chunk of what looked like cloud sitting there in a display case. At first I thought it was some kind of hologram. That was cool. But then I started reading about it, and BANG! New favorite.

Here's why:

By definition, an aerogel is a network of interconnected nanostructures which is at least 50% porous. It is an extremely low density solid matrix material (or foam) in which the liquid part of a gel (most often a silicone/oxygen gel) is replaced by a gas.

In other words, they dessicate the liquid out and fill the gel with air (thus the name aerogel). In fact, in a silicon-based aerogel, it's content is about 99.5% air and .5% silicon. This makes it look like a chunk of cloud Jell-o and feel like styrofoam. Its desiccating qualities can dry out the skin.

An aerogel can hold up to 2,000 to 4,000 times its weight if that weight is added carefully. Otherwise, it's extremely friable, meaning if you poke it too hard, or bend it, the gel (a misnomer as it's actually a solid) will shatter. It does, however, bounce!

They are extremely low in density--usually about 15 times heavier than air. In fact, all the lowest density substances man has yet produced have been aerogels. Some silicate aerogels, at 99.98% air, are only three times heavier than air and can even be lighter than air if the air is evacuated from the matrix.

If you stacked up 150 normal brick-sized bricks of aerogel, they would only weigh as much as a gallon of water. An aerogel statue of David would only weigh about four pounds.

Silicate aerogel is amazing stuff! It is the most commonly-manufactured of the aerogels so far. It's a fantastic thermal insulator (it can provide the same insulation value as fifteen panes of glass), absorbs infrared rays, but it can also allow light through, making it a great thing to use in windows. They used silicate aerogels in the Sojourner Mars rover in 1997 because of their insulation values.

NASA, in its Stardust Spacecraft mission (and others) used aerogels 'doped' with Gadolinium and Terbium to capture hypervelocity particles coming off of the Wild 2 comet. Particles shoot off of the comet at roughly six times the speed of a speeding bullet. As they hit the aerogel, the particles are slowed down and leave a florescent trail, making it easier to spot the tiny sand-sized particles.

Aerogels can be made out of other substances as well as silicon. Carbon aerogel makes a great supercapacitor and is now being used in solar collectors.

Alumina aerogels using aluminum oxide are being used in tandem with other metals as catalysts.

They're testing aerogels for use in insulating jackets and blankets, thermal diving suits, and as drug delivery systems. They're using it to absorb pollutants, and as flexible insulation in buildings--which won't age, mold, or mildew.

And, duh duh duh da...they've combined it with my second favorite substance (carbon nanotubes) to make carbon aerogels--a material so elastic that it might be used in chemical and pressure sensors. Carbon nanotubes can be grown in an aerogel, and they can also be used to strengthen the aerogel itself.

Samuel Stephens Kistler of the College of the Pacific in Stockton, California, created the first aerogel in 1931. He won a bet with his frhere.iend Charles Learned that he could replace the liquid in a gel with gas without making the gel shrink.

So sometime soon we'll be looking out of our aerogel-filled windows as we put on our aerogel-filled jackets. We'll walk out of our aerogel-insulated homes and then the possibilities will be wide open!

Sources:
http://www.Aerogel.org
http://en.wikipedia.org/wiki/Aerogel
http://www.aerogel.com/
http://www.youtube.com/watch?v=kHnen2nSmDY
http://stardust.jpl.nasa.gov/tech/aerogel.html
http://thermablok.com/
http://www.tonyboon.co.uk/aerogel/aerogel.htm