How wet is wet?

Dr. Witt defines water surface tension and shows examples of "wetted water." His daughter Marilyn performs an experiment floating a steel needle on water until an additional drop of water breaks the surface tension and sinks the needle. Dr. Witt demonstrates how the surface of a glass plate treated with a wetting agent stays clear and unfogged as the water spreads into a thin film, unlike the untreated surface, on which droplets formed spheres that cloud the glass. This technology is used on skin diving masks and windshields of airplanes and cars. Dr. Witt compares "wetted water" and regular water in laundry uses. Wetting agents also allow mixing of oil with water to make stable emulsions for such products as agricultural sprays, paints and dyes, cosmetics, and floor waxes. In addition to synthetic wetting agents, there are also natural ones such as egg yolks. Dr. Witt shows how a warm carbonated beverage, as an unburnable emulsion, can be used as a fire extinguisher to put out small fires.