World’s Lightest Solid Substance

Are jellies solid or liquid? Well, they’re both, kind of. Gelatinous substances like Jell-O are mostly liquid, but are held together by a fine solid mesh that helps the liquid keep its form. In 1931, American chemist Samuel Kistler had an idea to replace all of that liquid with gas. The resulting material, aerogel , is a solid chunk of transparent material that is the most lightweight solid in the world, and which is an excellent heat insulator that has many applications in science and industry.

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