Halloween and Dry Ice

My kids' Montessori class held their annual Halloween luncheon today.  On the menu:

• cheese sandwiches cut into ghost and jack-o-lantern shapes with red pepper pieces for accents
• frozen banana "ghost" pops
• carrot "fingers" using ranch dressing to attach pepper "nails"
• cupcakes with skeletons on the top (the skull made out of marshmallows)
• cupcakes with candy corn decorations
• apples made into creatures using olives for eyes, strawberry slices for mouths (attached with toothpicks) and pretzels for arms
• apple slices made into the shape of mouths
• little pizzas made to look like mummies

and...

• a witch's cauldron of fruit punch (ginger ale, cranberry juice, orange juice and lime sherbet - a recipe from my childhood) with gummy eyeballs floating in it, sitting atop a block of dry ice to get that "spooky" effect.

All of them were fantastic and the kids loved them!

The last one (the cauldron) was my assignment.  I had never worked with dry ice before.  My first encounter with it included a superficial burn on my fingertips as I tried to haul it from the freezer case at the grocery store several days ago.  Good grief, that was painful!  I had totally overlooked the sign on the top of the freezer case: Do not directly touch!

So I got it home and popped it safely into my deep freezer.  "All set," or so I thought.  This morning, as I packed up my supplies for the party, I pulled the bag of dry ice from the freezer.  Empty!  It was totally empty!  $15.60 worth of dry ice totally evaporated in my deep freezer!  Turns out, at temperatures above −69.5 °F (which I'm pretty sure is beyond my deep freezer's capability), CO₂ changes from a solid to a gas with no intervening liquid form, through a process called sublimation.  Just as regular ice evaporates in heat, dry ice disappears when exposed to air, even in a very cold environment.  Excellent.

So, already late to school, I paraded into the grocery store with my two kids, dressed as a bumble bee no less, to get more dry ice at 8:30am this morning.  But the result?  Spectacular.  The kids loved it!

Please note: if you're planning on doing a similar project, do not forget that the dry ice does NOT go into the drink.  Place it in a tub with some hot water to get the "smoke" going, then place a separate tub of punch on top of the dry ice.  Keep adding hot water to the outer tub to keep the smokey effect going.

Happy Halloween!