Idea picked up at USST convention;
Kids wanting to learn about the earth's layers and how the fold mountains are made can make these and eat as a snack at the end (has a more lasting impact).
Each cooperative group of four children make a layered model of the earth with tortilla on bottom, refried beans spread across this, quacamole on top of that and shredded cheese on top of this. Heating not necessary. Top off with another tortilla and then on waxed paper or clean surface have one student push together both sides with his clean hands to demonstrate the way mountains are formed in layers. At the end cut in four or more pieces and eat it.