Liquid Nitrogen Soap Suds Explosion

I saw this demonstration on the "David Letterman Show" and just had to try it. It simply involves quickly pouring liquid nitrogen (WARNING: Extremely COLD!) into hot water (WARNING: HOT!) containing dishsoap. The liquid nitrogen flashes to nitrogen gas, causing a large explosion of rather cool soap suds. This demonstration is best done outside since so many suds are produced. An awesome demonstration of phase changes!

BELOW LEFT: The soap suds explosion.

BELOW RIGHT: Aftermath of the soap suds exposion. I got suds all over me from this one (note the suds on the step rails and on the ground).

Kylee Korte, Phuong Nguyen, and Joel Kouakou assisted in preparing this description.

CAUTION: Liquid nitrogen is very cold and presents a serious frostbite hazard, especially if it gets trapped against your skin (e.g.in your clothing). Additionally, gaseous nitrogen occupies more volume than the same quantity of liquid nitrogen. Gaseous nitrogen produced quickly enough in sufficient quantities can displace oxygen from the air. Containers filled with liquid nitrogen could fail without warning due to thermal shock or gas pressure. Protect yourself accordingly.   For a scary story about liquid nitrogen hazards, see: http://www.wpi.edu/news/19989/nitro.html.