Spent the afternoon with my kids conducting research into the various methods of making Sprite bubble. Mentos came out on top, testing better than Nerds, Skittles, Runts, Tootsie Roll, mints, Laffy Taffy, regular taffy, or Smarties. The biggest problem with making the Mentos soda fountain is the delivery--getting all the candy into the pop bottle before the erupting soda blocks the mouth of the bottle. Turns out somebody has actually invented a gadget for this very purpose, a Mentos loading tube, selling for $4.98 (http://www.stevespanglerscience.com/product/2072?gclid=CPjW34z4v5wCFQ6jagod23qhnA.)
I'll stick to paper funnels for now.