Dry Ice

We got some ice cream today, and they packed it in with dry ice.
Obviously, when I got home, this meant time for fun. I first dropped
some in a cup of water and got that to bubble and fog. But then an
idea hit me: I put some in a used spring water sport bottle, and let
the pressure build up until the valve on top popped. Hmm... releasing
gases... That's when I put the drip of dish detergent into the cup.
Sure enough, a column of foggy bubbles began spilling over the edge
in what one might call a stable foam. I then put a drop or two in the
sport bottle, as you see there above. Quite fun!