Imagine a clear speaker, lining your windows, that can double to actively silence the outside world. That system is here right now. Sort of.

Scientists at Harvard University have developed a transparent speaker that can work across the entire range of human hearing. Check out the video to hear it in action.

So how has science made this seemingly fictitious technology possible? Simply speaking, two layers of saltwater gel are sandwiched around a rubber sheet which vibrates when voltage is passed through it. This means that not only is it transparent but it's also stretchable.

This bendable, transparent speaker could be a step in the direction of wearable tech that blends seamlessly with our bodies. But in a more future-gazing way, it could also blend into our bodies. These gels are ideal for implants in humanss, with suggestions that they could be used for artificial muscles.

Co-lead author Christoph Keplinger says: "We’re really approaching the type of soft machine that biology has to offer." Like a friendly, more huggable version of the Terminator 1000 then, we'd imagine.

But for now we'd be happy with a gel speaker stretched over our windows, hooked up to a mic recoding outside noise, and vibrating the opposite sound in – which is how active noise cancellation works. Now we just have to find some salt water gel and see-through rubber.