Coupling virtual environments with different physical environments can simulate or create novel experiences and sensations. Here, one method is explored by combining a virtual environment inspired by outer space shown in a head-mounted 3D display while neutrally buoyant in a swimming pool.

Background

NASA's Neutral Buoyancy Laboratory
Sensory deprivation chambers
Vilayanur Subramanian Ramachandran
Henrik Ehrsson’s laboratory at the Karolinska Institute
Mobile computing
Disney Viewmaster

Implementation
The end product is a working waterproof heads-up display that can display a 3D virtual environment underwater and can respond to the wearer's physical actions. The quick method towards getting that done is to use an iPhone as it has the processing power, the display screen, and the sensors (gyroscope, specifically). This combined with a modified toy akin to the classic Disney Viewmasters for the iPhone screen allows for a quick, direct exploration of the idea. Scuba training in order to safe and properly achieve neutral buoyancy is also required. The virtual environments displayed underwater use Unity for the environment and Rhino for its modeling software. The actual waterproofing for everything involves a good lot of silicon glue, a classic oval diving mask, and rubber diving tubes.