Hydrogel Speakers Stretch Across Screens to Play Music

An invisible, music-playing and sound-canceling gel may soon coat your smartphone, laptop screen, television, and even your car windows.

This stretchy hydrogel speaker, a prototype invented by a team of Harvard University scientists, was created by combining saltwater and polymers that are then hooked up to electrodes. A thin rubber sheet is sandwiched between two layers of gel, and ions carry a current in the gel that vibrates the rubber to make sound waves. The process is not unlike the way the human body transmits electric signals that tell the heart to beat, which is where the Harvard team got its idea. Read more...