Silica gel was invented in 1919 by Walter A. Patrick, a professor of chemistry at Johns Hopkins University, and was used as an absorbent in gas masks during World War I. Silica gel can refer to the condensate of silica alone, or it can refer to organic and inorganic silica gel in general. We often hear a word called "silicone", and "silicone" is often referred to as silicone, but the fact...