Wine and water exchange places physics experiment

Cover up a glass of water with a thin pasteboard, turn it over and put it on the glass of red wine. Brims of both glasses have to be completely covered. Pull out the carton to make a tiny gap between the glasses. Vine which is less dense than water immediately starts to lift up to the upper glass, while water slips to the lower glass. In a while the liquids will change sites, all wine will be in the upper glass and water in the lower glass. The narrow gap doesn t allow fluid mixing.