Aerogel

Aerogel is a highly insulating material composed mainly of air, made by removing liquid from a gel and replacing it with gas. It appears as a lightweight, translucent solid, often called "solid smoke." Despite its fragile and delicate appearance, it has remarkable insulating properties because its porous structure traps air, which reduces heat transfer. Aerogels are used in various applications, including insulating spacesuits, windows, and buildings, due to their ability to prevent heat flow effectively while being extremely light and thin.