Ok, I'll sit it out knowing the water will evaporate, and leave the colouring behind. I promise not to touch it
You introduced this disorder, not I, I just sat and fell asleep watching it.. remember your up against someone who will get to the truth of the matter, in that you chose water, knowing it would evaporate of it's own accord, I had no say in this scientific fact, I merely debunked the question, using nothing.
Edit: twas a good question, you had me thinking, but it is also an invalid question with regards to your point, due to the fact you forgot water is constantly changing.