In microgravity…you don’t need a container. In Day’s initial experiments, the melt–a molten droplet about 1/4 inch in diameter–was held in place inside a hot furnace simply by the pressure of sound waves emitted by an acoustic levitator. With that acoustic levitator, explains Day, ‘we could melt and cool and melt and cool a molten droplet without letting it touch anything.’ As Day had hoped, containerless processing produced a better glass. To his surprise, though, the glass was of even higher quality than theory had predicted. [via] Link.
Making glass in Space