The Little Passports Utah State Journal has a neat experiment to learn about how sedimentary rocks are formed.
Materials: 3 slices of different breads, paper towel, 4+ gummy dinosaurs, ruler, straw, heavy books
Remove the crusts from the three different breads. We used wheat, white and sourdough. Place one piece of bread on a paper towel, then put two gummy dinosaurs on top. We didn't have gummy dinosaurs, but we did have vanilla tootsie rolls leftover from the Edible Geology experiment. I cut one into pieces that we shaped into dinosaurs. Put a second piece of bread on top, then add more dinosaurs on top. The last piece of bread goes on top of that.
Measure the height of the stack.
Put a paper towel on top and then cover the stack with a heavy book overnight. It'll be much thinner in the morning!
Pressure caused the layers to compress, trapping the dinosaurs inside. Use the straw to push straight down into the 'sedimentary rock' to collect a core sample. You'll be able to see the distinct layers, and you might unearth a dinosaur fossil.