Kids, you can use sublimating dry ice to produce carbon dioxide gas to fill bubbles. Here we will give you three variations for this experience, beginning from simple and gradually getting a little more complex.
Please note: All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.
Small Bubbles. A small piece of dry ice can be used to produce cloudy bubbles that will last for a long time. Pour a little bubble solution into a bowl. If you don't have bubble solution, swish a small amount of liquid dishwashing detergent into water. Ask an adult partner to use tongs or gloves to pick up a piece of dry ice and add it to the bubble solution. That's it!
Giant Bubble. All you need to make a giant bubble is dry ice, bubble solution, a paper towel or cloth rag, and a little water. The dry ice sublimates to form carbon dioxide gas, which expands the bubble. Pour some water into a bowl. Have an adult partner add a piece of dry ice. The dry ice will make bubbles in the liquid. Use a piece of paper towel or a rag that has been wetted with bubble solution to smear bubble solution across the whole top surface of the container. What happens?
Glowing Bubbles. You can make the bubbles glow by adding a little highlighter ink to the bubble solution. For the giant bubble version, you can try tonic water instead of tap water, and use a black light.
How It Works
Dry ice sublimes in air, meaning the solid carbon dioxide changes into carbon dioxide gas. This process occurs much more quickly in a bubble solution than in air. As the dry ice sublimes, 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.
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By Kathleen Carrado Gregar, PhD, Argonne National Labs
[email protected]
February 2014
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References:
Anne Marie Helmenstine in About.com Chemistry:
http://chemistry.about.com/od/dryiceprojects/a/dryicebubbles.htm
http://chemistry.about.com/od/dryiceprojects/a/dryicebubble.htm
