Indices of Refraction: glass in glycerin and phantom crystals.

Optical Illusion: Matching indices of refraction. In setup #1, the 'Phantom Crystals' (a highly hydrophilic carbon-based polymer) have been soaked in water until they've absorbed up to 300x their mass. Although they are clearly visible in air, when they are dropped into the beaker of water, they seemingly disappear. In setup #2, a pyrex rod is placed into a beaker of glycerin. Due to their relatively similar indices of refraction (1.473 and 1.474, respectively), only a very faint outline of the rod is visible.