To begin the lesson it is important to review the three types of rocks: metamorphic, igneous, and sedimentary. I makes sure that students can tell me about each type and I give them examples of the three types. For metamorphic we talk about how it is made from pressure and intense heat. An example of this would be marble. Next, I explain igneous is created when magma cools very quickly and almost forms a glass like appearance. The example I give is obsidian. Obsidian can be found around Flagstaff and students really like this one. The last one we discuss is sedimentary. We talk about it being a rock that is formed in combination with other particles like sand. The example I give is sandstone and limestone which are also common and are easy to point out where student might have seen this rock.
To understand the layers that are found in the canyon, I explain that we need to look at each layer individually. Each team or individual student will get a color of clay or play dough in order to create a specific layer of the canyon. Student will take their ball of clay and spread it out flat in order to give it a layer. Along with the each piece of clay, students are given an item that might have been found fossilized in that particular layer. This includes a card that explains the layer they are creating. Students are then given time to flatten their clay and add the imprints of their fossils into the layers.
Next, I call out the layers and the facts that are included on the cards in each kit. I ask this student to come to the front of the room to add their layer to our class model. Makes sure to start with the bottom layer and add each one on top of it. Student will come up and add layer on top of layer in order to build the Grand Canyon. At each one the students tell what can be found in their layer and add any facts. At this time, students can write the layers into their science journal and add notes too.
To help students remember how these layers were formed and ultimately created the Canyon, I teach students the mnemonic DUDE: Deposition, Uplifting, Downcutting, and Erosion. Deposition is the first D and explains how oceans a very long time ago deposited layers of rock, sand, and sediment to begin its formation. U is for uplifting. Uplifting refers to pushing up of the earth by the plates. The second D is for Downcutting. Downcutting is the Colorado River cutting through the rock. Finally the E is for erosion. Erosion is not just from the water, but also from the freezing and cracking that causes significant erosion changes.
I have students add the mnemonic to their science journal to help them remember how the Grand Canyon was formed and the significance of its layers.