Mountain Of Water

Fill a dry glass just full with tap water, without any overflowing. Slide coins carefully into the glass, one after the other, and notice how the water curves above the glass.

It is surprising how many coins you can put in without the water spilling over. The water mountain is supported by surface tension, as though it is covered by a fine skin. Finally, you can even shake the contents of a salt cellar slowly into the glass. The salt dissolves without the water pouring out.