Aerogel World's Lightest Solid

Aerogel is basically a synthetic porous ultralight material made from a gel, in which the liquid component has been replaced with a gas. Despite its name, aerogels are solid, rigid, and dry materials that do not resemble a gel in their physical properties. The material is 98.2% air, thanks to the lack of solid material, allowing it to be almost weightless. Continue reading for a video demonstrating what it sounds like when dropped.

Pressing extremely firmly will cause a catastrophic breakdown in the sparse structure, causing it to shatter like glass – a property known as friability; although more modern variations do not suffer from this. Despite the fact that it is prone to shattering, it is very strong structurally. Its impressive load bearing abilities are due to the dendritic microstructure, in which spherical particles of average size (2-5 nm) are fused together into clusters.