Aerogel is a material with the lowest density of any known solid. It is derived from a gel in which the liquid component of the material has been replaced with a gas. It has notable effectiveness as a thermal insulator. It is nicknamed ‘frozen smoke’ due to its translucent nature and the way light scatters in the material; however, it feels like expanded polystyrene (styrofoam) to the touch. Aerogel was invented by Samuel Stephens Kistler in 1931, as a result of a bet with Charles Learned over who could replace the liquid in ‘jellies’ with gas without causing shrinkage. Kistler’s first aerogels were produced from silica gels (his later work was based on alumina, chromia and tin oxide).
Despite their name, aerogels are rigid, dry materials and do not resemble a gel in their physical properties. Pressing softly on an aerogel typically does not leave a mark; pressing more firmly will leave a permanent depression; further pressure will cause it to shatter. Due to its hygroscopic nature, aerogel feels dry and acts as a strong desiccant. Persons handling aerogel for extended periods should wear gloves to prevent the appearance of dry brittle spots on their skin.
The Daily Omnivore 