Editing Liquid Nitrogen Show (section)

===Exploding Soap Bubbles===

Preparation: move the presentation thermos either into a large bin to catch overflow, or place on a tablecloth on the ground. If outdoors, place one the ground, making sure that students give it at least 10 ft of clearance. Make sure the presentation thermos is less than half filled.
# Show the container with the soap and water solution to the audience. Explain the expansion rate of Nitrogen, from liquid to gas.
# Have the students give you a countdown, and at the end of it dump about two cups of the solution into the liquid Nitrogen. There will be a dramatic explosion of bubbles!
# After a couple of seconds, take the ladle and carefully scoop some of the bubbles that are still within the thermos out. They will be frozen!