- dry ice
- bubble solution
- water (or tonic water and a black light, if you want glowing liquid)
- glass or dish
Make a Dry Ice Bubble
- Pour some water or tonic water into the container.
- Add a piece of dry ice. The dry ice will make bubbles in the liquid.
- Spread a film of bubble solution around the lip of the container.
- Use your hand or a piece of paper towel that has been wetted with bubble solution to smear bubble solution across the top of the container. I made a video of the project so you can see what to expect.
How It WorksDry ice sublimates in air, meaning the solid carbon dioxide makes the transition to carbon dioxide gas. This process occurs much more quickly in water than in air. As the dry ice sublimates, the carbon dioxide vapor is caught inside the bubble solution. The bubble expands, but the cooled bubble solution does not evaporate quickly so the bubble lasts for a relatively long time.
Sometimes conditions are right for the bubble to stabilize at a given size. This happens because carbon dioxide is able to diffuse across the bubble surface. Sublimating carbon dioxide expands the bubble, but when the bubble expands its walls become thinner and leak more. Since more carbon dioxide can escape, the pressure is reduced and the bubble has a tendency to shrink back again. As long as the solution doesn't evaporate too quickly, the bubble may remain relatively stable until the dry ice is nearly gone. At that point the bubble will become smaller.