Sometimes food makes the best object lessons, and this classic layered cookie bar was a yummy way to illustrate the rock cycle.
We started with “igneous rock” graham crackers. (Pretty sure I said something like “poop” so they’d smile for the camera. Oh, the drama of having a mom who wants to take photos of everything!)
The crackers went into the food processor, we turned on the “weathering and erosion” and ended up with lots of “sediment” (graham cracker crumbs).
(In hindsight, putting the crackers in a Ziploc and letting them “weather and erode” with a rolling pin might have been more fun, but I wasn’t in the mood to clean up the mess.)
Then we placed the cracker crumb “sediment” into a baking dish, added melted butter, and “compressed and compacted” the “sediment” to form the first layer in our “sedimentary rock.”
We added more sediment layers of gooey sweetened condensed milk “mud;” coconut flake “shells, plants, and debris;” and chocolate chip “rocks.”
Then we applied pressure (gently press) and heat (350F oven) to change our sedimentary layers into delicious metamorphic rocks.
Rock Cycle Cookie Bars
- 2 packages graham crackers (about 16 crackers)
- 1/2 cup melted butter
- 1 can sweetened condensed milk
- 1.5 cups shredded coconut
- 1 cup chocolate chips
- 1 cup chopped nuts (optional)
Crush graham crackers to crumbs. Mix butter with crumbs and press in the bottom of a 9×13 baking dish. Pour sweetened condensed milk evenly over crust. Top with remaining ingredients and press down. Bake at 350F for 25-30 minutes. Cool completely before cutting.