Which chemicals can produce a color change from clear to opaque and back again in water?
I am a professional Magician designing a new stage illusion, and I have specific requirements on a particular step of this illusion. This will require that I can take what appears to be normal water, and change the color of it so that what is submerged in the water cannot be easily seen through a clear container. Later I need to be able to reverse this color change so that the "water" appears to be transparent again.
Specifically, in my research done on my own I have come across a method in which potassium Iodide is created through a clock reaction. My concern here is whether or not the Iodide will stain as this effect requires that I submerge my hands in the water/solution.
Next involves Phenolphthalein and Sodium Hrdroxide but I have several concerns with this method in that the deep red color achieved at Ph 10 may not be opaque (hard to tell from pictures) enough for my needs, and whether or not the ph 10 solution would be caustic enough to cause chemical burns.
If there are any other chemical methods that can be used that fit the bill of being reversable, safe for skin contact, and non staining I would greatly appreciate any information you have.