I want to hunt down some of those dialectric mirrors. Their non-isotropic reflective materials sound pretty cool.
I am amazed that there is no metal in the material. It's just made of transparent polymer layers in alternating materials with different indices of refraction.
Has anybody out there actually been to the Exploratorium out in San Francisco? I assume it's a great science museum, but I've never actually been to San Francisco.
The video above shows an experiment comparing the index of refraction of pyrex (borosilicate glass - the rods that disappear) to that of, I assume, soda lime glass (the rod that stays visible). Pyrex has a nearly identical index of refraction as does corn or vegetable oil (and mineral oil, too). Because of that, Pyrex 'disappears' when soaked in corn oil.
For a slightly more theatrical presentation, check out Steve Spangler's take on the same experiment.
The demo also works with ghost crystals...
I've also heard that it works with colorless gelatin, but I haven't found a video of that, and I haven't tried it at home...yet...
The mineral oil or vegetable oil that the presenter mentions here are a little less messy to use in the demonstration, but the index of refraction with those isn't quite as perfect a match as glycerine (or glycerol) is to the borosilicate glass.
In the summer camps we demonstrate this with three types of glass - fused silica, borosilicate, and soda-lime glass. It's only the borosilicate that disappears, so the type of glass you use certainly does matter.
