# Why does the glass move?

I have observed at my home that when there is a small puddle of water on a glass table and an inverted steel glass is kept on that puddle of water, the glass starts moving on its own after some time.

I was wondering how that was happening . I think it is due to the fluidity of water due to which the water flows and the glass also moves along with that flowing water. But then I am confused, how can such a small amount of water get adequate amount of energy to move a glass?

Is my reasoning correct? Or there is some more physics behind it?

(PS : I do not know the real reason behind this , so please excuse me if the tags I have given are incorrect.)

Due to the slightly higher pressure $$p$$ inside the glass it's kept afloat while the inside pressure is maintained because of the seal. The slight over-pressure arises when the glass 'sinks' into the water layer and is caused by the weight of the glass, which slightly compresses the air 'trapped' between the glass and the seal. The over-pressure ensures the glass never really touches the table, making movement almost frictionless.