Place some dry ice on the bottom of an empty aquarium tank. Let it si
t for a while, so that a layer of carbon dioxide forms at the bottom of the tank. Then gently blow soap bubbles over the tank. The bubbles will sink into the tank and then stop, floating in mid- air. (The air in the bubbles is less dense than the purer CO2 at the bottom.) Very cool.
You can see a more complete description at
http:// www.exploratorium.edu/snacks/ . Scroll down until you see "Bubble Suspension".
http://www.exploratorium.edu/xref/exhibits/bubble_suspension.html
BTW, many of these Exploratorium Science Snacks make very good Science Fair projects for 9-12 yr olds. "Eddy Currents" is also a favorite with my students. It completely mystifies most adults!
Thank you John!!!!!
