Number 92 (Story #4), August 19, 1992 by Phillip F. Schewe and Ben Stein "SEAGEL" IS THE LIGHTEST SOLID . Produced by Robert Morrison at Lawrence Livermore National Lab, Seagel is made of agar from kelp, and contains only 40 to 50 mg of material per cubic centimeter of solid. (New Scientist, 15 August 1992.)