Hit sudden turbulence over The Rockies once, just as the drinks had been served. Ahead of me a wine glass (fortunately plastic) described a parabola from a tray up towards the ceiling and back down again having travelled about 3 seats forward. The red wine contents, having a different specific gravity, described a different parabola, and steadily left the glass, attained a slightly higher altitude, and then came down in a single mass all across some poor guy about two seats further forward again. It was just like something you see in a Mickey Mouse cartoon.