The world's lightest known solid – Aerogel

Ever wondered what would happen if you took glass and made it really really fluffy? No? Well I’m going to tell you anyway. Aerogel is the answer. It’s awesome – it holds 15 Guiness World Records, and is the lightest and lowest density substance known to man.

So what is it? Well, it’s 99.8% air for starters. The rest is silicon dioxide – glass. It only weighs 3 times as much as air occupying the same volume, and it’s a damn good insulator too. A one-inch thick slice of Aerogel has the same insulation value as 15 panes of glass with air in between. NASA use it to insulate their Mars rovers.

It also can support thousands of times its own weight. A block weighing 450g can support nearly a tonne. It will also shatter if you drop it, just like glass, and it’s a powerful dessicant – drying up an moisture on your skin quite uncomfortably if you touch it. If you drop it in water, it sounds like rice crispies, as the air gets forced out of the tiny compartments. It doesn’t burn. It doesn’t freeze (it’s solid already). Its melting point is 1,200°C. Microwaving it has no effect, becuase there’s no water in it.

A chap called Jason R Wells has put it through its paces properly, doing all kinds of home experiments to test different properties of Aerogel. He soaks it, roasts it, zaps it, wraps it around a hot dog, and so on. It’s a great read, and he goes into all kinds of crazy detail. Highly recommended!

You can buy Aerogel, or if you’ve got the science skills of a ten-year-old, you can even make your own.

Kitchen experiments with Aerogel (via CrunchGear)

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