The first exposure most of us have to dry ice is a punch bowl at a Halloween party. Dropped into the punch, a block of dry ice bubbles and churns while releasing a thick fog of carbon dioxide gas which adds to the spooky atmosphere of the party.

Many years ago my friend Andrew Tepper turned me on to the recreational use of dry ice. He filled an old fashioned corrugated washbasin with hot soapy water and then dropped in a block of dry ice, creating a substance he called blob foam. As you know, dry ice does not melt at atmospheric pressure. It sublimates, going directly from the solid to the gaseous state.

WARNING: Improper handling of dry ice is dangerous.

Any responsible adult who actually tries this must accept liability for any deaths, injuries, and/or property damage it causes. If you are not a responsible adult (in the legal sense), don't even think about it. Bare skin exposed to dry ice can instantly develop frostbite or 'freezer burn'. A small quantity of dry ice stored in a sealed container can cause a large explosion. Breathing the concentrated CO2 fumes from dry ice can cause asphyxiation, unconciousness, and death. This article is presented merely for entertainment.

My friend Andrew Mill and I were playing with dry ice at a barbeque. We had to stop blowing up soda bottles because we were antagonizing the neighbors, so we had to find a use for our remaining dry ice

Remembering Andrew Tepper's blob foam, we decided that tossing dry ice onto the hot grill would generate an impressive plume of carbon dioxide. We donned our safety gloves, grabbed a handful of dry ice pellets, and tossed them onto the hot grill expecting a nice cloud to form.

Nothing happened.
We followed the instincts wired into our hominid brains (we poked it with a stick).
	Still nothing.

It turns out that placing dry ice in contact with the hot coals released enough carbon dioxide to starve the coals for oxygen. It also caused a fuzzy snow-like coating to form on the dry ice pellets. We're not sure if the snow was water or carbon dioxide, but it probably acted as an insulator and slowed down the sublimation rate.

When we removed the dry ice the coals started burning again. Our next experiment will be to upset the equilibrium by using a forced air burner of some kind.