This erupting volcano project rolls a cooking class and a science experiment into one. The volcano, which is completely edible, is made of cake, frosting and other sweets. The foaming lava, made of Jello and baking soda, does nothing to detract from the treat's appeal. This is a great project to do for a science fair or with an entire class of children.
Place a cookie sheet on a flat surface. Invert the quarter-sheet cake on top of the cookie sheet. Center the Bundt or tube cake on top of the quarter-sheet cake. If the top of the Bundt or tube cake is too wide, stack a couple layers of small sandwich cookies on top to give it some height.
Divide the cake icing into two batches and mix in the food coloring. Half of the icing should be brown (for the volcano) and the other half should be green (for the island beneath it). Ice the cakes, making the Bundt or tube cake brown and the quarter-sheet cake green; the two colors will meet around the base of the volcano.
Decorate the cake further, if desired. Paint the area around the volcano opening with drizzles of red gel icing to simulate lava. Crush graham crackers to dust and sprinkle it around the edges of the island for sand. Fill the empty areas of the cookie sheet with blue candies, such as M&Ms or Skittles, for water.
Make the Jello according to the instructions on the packet and allow it to cool for about 15 minutes. Using a funnel, fill the small juice glass about halfway with the warm liquid Jello. Fill the glass almost to the top with lemon juice.
Slide the juice glass into the hole in the top cake. Make sure the glass fits snugly into the hole and that the top rim of the cup sits flush with the top of the volcano. Set the glass on top of some sandwich cookies to raise it up, if needed.
Put 1 tablespoon of bicarbonate of soda into the juice glass and stir. The Jello mixture should foam up over the edge of the volcano. This is why the fit is so important; if the glass sits loosely in the hole, the lava will get stuck in the hole. If it isn't high enough, the lava won't foam out over the top.