Transparent gel speaker plays music through the magic of ionic conduction (video)

It may be hard to believe, but that transparent disk in the photo above is actually a fully functioning speaker. A team of researchers at Harvard's School of Engineering and Applied Sciences have pioneered a never before seen application of ionic conductivity by creating a see-through artificial muscle that can produce sounds spanning the entire audible spectrum. While ionic conduction isn't a novel idea, it's been considered impractical due to the fact that ionic materials react poorly to high ...