Scientists create 'sound' invisibility cloak -

With work well under way to create a working invisibility cloaks in labs across the world, the good news for the less light-footed wannabe superheroes is that acoustic cloaking is in the pipeline too.

Current methods to make an object appear invisible to the naked eye work around a principle of guiding light waves around the object.

According to researchers at the Karlsruhe Institute of Technology, the same principle can also work with other waves such as sound waves.

They have now succeeded, they say, in developing an 'invisibility cloak' that can mask the sounds emanating from ‘elastic waves’, waves that occur in the strings of a guitar or a drum membrane.  We can only hope that the KIT researchers will be working closely with Justin Bieber’s production team in the near future.

The experiment involved using a microstuctured material consisting of two polymers to make a soft and a hard plastic in a thin plate. When vibrating, the sounds of the plate can be detected audibly from above.

The sounds waves are guided in a circular area around the thin plate, with the vibrations unable to leave the area.  Unlike other methds, though, the sounds are neither absorbed or reflected according to the researchers.  “It is as if nothing were there,” Professor Martin Wegener at KIT said, though he was a bit hard to hear.