How do sensory deprivation chambers work? --- Charles, Mildmay, Canada
The basic idea behind a sensory deprivation chamber is to eliminate as much sensory information as possible. It is easy to eliminate visual information by creating complete darkness. From there everything else assumes the participant's cooperation. For example, with sufficient insulation and sound-proofing, it is possible to eliminate all outside sound. Music studios do this all the time. But the person inside the chamber can easily create sound with voice or movement. Smell and taste are similar.
Eliminating the sense of touch is nearly impossible, but is usually attempted by floating in near-body-heat water. The following video shows a typical flotation tank:
Closing the door of a chamber like this eliminates light and sound. This is about as close as a person can get to total sensory deprivation on Earth.
In the following video you can see why the salt is added to the water. It reduces the risk of drowning by making the water heavier and therefore causing the person to float higher:
As described in this video, most people have a problem with sensory deprivation (even at the level of just sight and sound) when the depreivation is not voluntary and when they are forced to endure it for extended periods of time.