Aerogel: The Strange Solid That's Mostly Air

Imagine a material that’s almost lighter than a feather – so light it’s 99.8% air – yet solid enough to support a brick. It looks like a piece of ghostly blue smoke, but you can hold it in your hand. This isn’t science fiction; it’s aerogel, the world’s lightest solid. Aerogel earned the nickname “frozen smoke” for its wispy appearance, and for a time it even held the Guinness World Record for lowest-density solid. Despite being mostly air, aerogel can be remarkably strong and an excellent insulator. In fact, it can protect a flower from the heat of a flame – a visual demo that has captivated many observers. What started as a laboratory curiosity is now a material with out-of-this-world applications (literally – NASA has used it in space), as well as down-to-earth uses here at home.

Photo “Aerogel!” by jon collier, CC BY-SA 2.0