Comet-Making  Ingredients and Equipment

Dry Ice: about 1 lb  Can be obtained cheaply from party suppliers and in smaller quantities from ice cream stores. Wrap in newspaper and store in an ice chest. Don't handle it without protective gloves, as it can damage the skin.
Ammonia: Dash -2 Tbsp.  An organic substance, and cheap at hardware/grocery stores.
Dash of Corn Syrup:  Dark is better, as the color reveals the presence of carbon.
Water: 2 cups +extra A good item to pre-measure into cups.  Have some extra on hand for adjusting the mixture.
Dirt/Sand: 2-4 Tbsp.  You can use sandy backyard soil (as long as it doesn't have obvious life forms), or sand from a construction site or  a garden/ building supplier.  A mixture of carbon granules and vermiculite also has the two necessary components, carbon and silica.
Mixing Bowl: 4 qt. or larger It's better to have a plastic or wood bowl, because metal will get very cold. Tupperware, plastic plant pots, and even ice buckets can all work.
Mixing Spoon: Again, wood or plastic is best, and it should be pretty strong. A metal spoon will get very cold; you may have to wear gloves to stir, but it will work.
Trash Bags: 2-3 lrg. waste basket- sized Heavy weight wastebasket or garbage can liners. These are used both to line the mixing bowl and to hold dry ice during crushing.
Hammer or Mallet, Chisel: For crushing the dry ice. A construction hammer or wooden mallet is ideal, as you want something fairly large with a broad striking surface.
Work Gloves and Goggles: Teams should have safety equipment for the person handling the dry ice and doing the stirring.
Paper Towels: For cleaning up spills.
Ice Chest:

For storing dry ice.  You can use a cheap Styrofoam model if you don't need to store the dry ice for long.