What liquid should you use to wet a piece of cloth, so that weight of a wet cloth is less than weight of a dry cloth?
The only idea I have is that you should wet the cloth in sunflower oil and then immerse it into water. It won't sink, because the oil won't let the water to soak cloth, so the cloth will float. But it still has its weight (it' putting pressure on the water) and it weighs more because it has oil in it.
So I'm comletely stumped here.
I know, that this question was offered in the university course of molecular physics.