I think everyone should have seen a bowl of hot water moving by itself on a flat surface such as glass(seems like it is moving by itself but maybe there are some external force applied to it when it moves). What is the explanation of this phenomenon?
Since the bowl is heavy, for it to move the friction between the bowl and the surface must be very very low. I have heard that water may form a thin layer between the bowl and the surface, but l'm not sure whether it is the case or not.
I think the bowl can move by itself because heat makes the air below the bowl expand.
Edit : I will re-experiment those again and update the question in few days. Maybe I will take a video clip too. and I am not talking about a magic trick whatsoever.