Mushroom Cloud

DESCRIPTION:
When dry ice is placed in warm water it sublimes very quickly forming a large amount of carbon dioxide gas. When a bubble is placed over this the bubble grows from the pressure.

TOPICS COVERED:
cryogenics
physical change
pressure
sublimation
surface tension

MATERIALS NEEDED:
– a beaker ~3/4 full of warm water
– a dry ice pellet and tongs
– strip of cheesecloth that has been soaked in soapy water (a Sparkleen solution used to clean in labs, or a bubble solution from another demo will work)

PROCEDURE:
1. Place the dry ice into the water
2. Drag the cheesecloth strip over the top of the beaker so it forms a film

ADDITIONAL COMMENTS:
Food coloring in the water makes it easier to see.

SAFETY:
Dry ice is a cryogenic hazard and should be handled carefully and goggles worn at all times.

REFERENCES:
“Awesome Dry Ice Experiments.” Steve Spangler Science. Accessed 15 Jul 2011.
http://www.stevespanglerscience.com/experiment/dry-ice-crystal-ball-bubble

Handout