Grade Setting Theme/Bottom Line Description BIAS Time Recommended group size FOSS kit: Landforms State Standards: Earth Systems Science 3.

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Tyrone Woods
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1 HUMAN HOGBACKS the EPIC* 2012 Grade: 5th Setting: Prairie, classroom or field Theme/Bottom Line: What Colorado looks like today is not what it has always looked like. Description: Students participate in a demonstration of layering and uplift to show how the local landscape was formed, eroded and formed again BIAS: Stewardship Time: minutes Recommended group size- about 20 students FOSS kit: Landforms State Standards: Earth Systems Science 3.2 Evaluate evidence that Earth s geosphere, atmosphere, hydrosphere, and biosphere interact as a complex system. Earth s surface changes constantly through a variety of processes and forces. Materials: Colorado Landforms Rock Journals, clipboards, pencils (one per student) handed out at beginning of the day Human hogbacks kit (includes 6 towels ( red, sand colored, tropical, blue), objects to scatter (sand, fish, plastic pine trees, dragonflies, dinosaurs, water, shells). Each bag has an inventory tag on the bag detailing the contents. Sand and gravel, a clear container to show layering (optional) Copy of Ancient Denvers for the Historian Time line for the Timekeeper A rock and flat piece of rock. Procedure: 1. Introduce yourself and welcome students. Ask the students if any of them have a BFF best friend forever? Explain that you are thinking about having a BFF also but you are confused by what the word forever means. Let them give their explanations of the term and question what they say. i.e. is forever after you are gone? Does it include before you were born? What about if one of the friends moves away? The purpose of this is not to arrive at any one correct answer but to challenge them to think about time past, present and future. Nat Note: Time and chronology are concepts that are just forming for year olds. The BFF discussion will help to get them thinking about expanded time frames before you begin your activity. Eons are pretty hard to grasp. 2. Now switch to the geology theme by explaining that time past, present and future are what you will be talking about today. Somewhat like forever. Many people love living in Fort Collins because of the beauty of the plains and mountains. But what we see today in time present is not what it always looked like in time past. Today you are going to ask them to help you tell the story of

2 Body: Colorado in time past. What happened in these long, long periods of time (eons) past helps us understand why we see what we do in time present. But we also need to know that it will change again in time future. And all this happens VERY slowly! 3. Take out the rock you brought and the slab of rock. Use the rock to draw a mark on the slab. Ask if any of them have ever written on a sidewalk with a rock. Ask what makes the mark? Explain that the rubbing of the rock against the slab is wearing away a tiny, tiny bit of the rock. This is eroding the rock. Ask them how long they think it would take to wear away the whole rock. Compare this to the wearing away of the mountains. Ask them to remember this term erosion and the understanding of how slowly this happens as you retell the story of Colorado. 1. The landforms we see around us and what we think of as Colorado in time present is made up of layers. Ask the students to define layer. You can remind them of a layer cake or the layers in lasagna. Point out that usually we think of layers as horizontal, but sometimes layers get pushed up. That will happen in our story today. Explain that in geology the youngest layers are on top and the oldest layers are on the bottom. (Optional demonstration if the students seem to need it.) Pour sand and gravel in layers in a clear container to show that the one you poured in first is at the bottom. It is important to remember this when the layers start moving. 2. Next, have students look at their fingers when their hands are horizontal, thumbs on top, pinkies at the bottom. Ask which layer would be oldest if this were geology (pinkies). Have students bring their other hand up and match up index finger to index finger etc. Then show uplift by having students make their hands into a v shape. This is a very simple explanation of what happened to create our landscape- there were flat layers that got uplifted/ pushed up. It s okay if students don t completely understand at this point. 3. Now it is time to reenact the story of Colorado. Ask for some players to help you with this epic. Colorado: 1 player to lie down and be the Colorado. The Layers of Time Past: 6 individuals or pairs of partners to be the geological layers. (Bags 1-6) Timekeeper: 1 player to operate the time line and keep everyone in the correct geologic era. Historian: 1 player to show the book pictures that correctly depict the geologic eras. MN narrates story and shows the sample worksheet as you go. Or teacher could be the sample worksheet keeper instead, but not a student. 4. Do a brief review of the terms layer and uplift by asking the students to show with their hands layers and uplift. Review the concept of the oldest layers being on the bottom. 5. Show the sample worksheet and give directions for filling in each layer as the epic unfolds. Students may use either words or pictures to represent what Colorado looked like in each geologic time. 6. The Epic of Colorado:

3 (Bag #1)Begin the demonstration by having Colorado lie down on the floor/ground/picnic table on their back face up. Orient the student E to W, with head to the West. Explain that this person represents Colorado. We are beginning our story 300 million years ago. Lively streams flowed down from the mountains called the Ancestral Rockies. Ask Colorado to raise their knees. Point out box 1. Now cover Colorado with the red towel, laying it across the student s knees with the length of the towel running the same direction as the student s body. This layer is the Fountain Formation and it is made up mostly of small gravel and some bigger, harder pieces of rock. The Timekeeper adjusts and shows the timeline (300mya), and the Historian shows Ancient Denvers (pages 5/6). Ask Colorado to slowly lower their knees as Bag 1 players scatter gravel and pebbles on the towel on either side of the knees. Explain the ancestral mountains are eroding slowly and the gravel and small rocks are depositing next to the mountains. In other words the mountains are getting shorter and the land next to them is rising. Students fill in 300 million yrs ago section of the worksheet. Point out the ancient trees and the cockroaches, millipedes, dragonflies, amphibians and fish pictured in AD to help the students fill in their worksheets. (Bag #2) The next layer is the Lyons Formation. Cover Colorado with the tan towel and explain that on top of the Fountain Formation lies the Lyons Sandstone. Now Colorado is very dry. The winds pick up the dry sand from the eroding mountains and deposit it on top of the Fountain Formation. Bag 2 players scatter sand on the towel next to Colorado s knees. Have the Timekeeper adjust and show (280 mya) and the Historian show AD (p.7/8). Check to make sure everyone is in the correct layer on their worksheet. Students fill in Lyons, 280 mya section of worksheet. As they work you add Colorado is high and dry, with enormous sand dunes, like the present Sahara desert. The dunes are starting to bury the Ancestral Rockies. Over a long time the sands became very hard rock. The flagstone we use for our gardens and patios often comes from this layer. (Bag #3) Now it s finally the time of the dinosaurs! The Morrison Formation is the next layer. It is famous for its dinosaur fossils. Lay down the green towel and Bag 3 players scatter dinosaurs. Again ask the Timekeeper (150 mya) and the Historian (p.11) to circulate and show. Students fill in worksheet. As they work you add Colorado was hot, wet and green like a tropical forest tangled with huge ferns and plants. (Bag #4) The next layer is called the Dakota group. Lay down the orange towel. The Dakota is a formation deposited along the shore of a shallow sea that is growing larger and larger. It is made up mostly of mud and sand glued tightly together. That makes it very hard so that it stands out as a ridge in fact the one we see right here in Ft Collins. (Point to the ridge of foothills to the west.) Ask the Timekeeper (100 mya) and Historian (p. 13/14) to circulate and show. Bag 4 players scatter more sand and some plant leaves. Students fill in the worksheet. As they work add, in this formation you can see ripple marks from the waves of the sea and footprints of the dinosaurs where they walked along the shore.

4 (Bag # 5) Now we come to the Pierre Shale layer. Cover Colorado with the blue towel (This towel is cut in half. Overlap the cut slightly.) Bag 5 players scatter water, and shells. The sea that was growing when the Dakota formation was laid down is now 600 feet deep - and covers Colorado. The Timekeeper (70 mya) and Historian (p.15/16) make their rounds. Students fill in worksheet. As they work you explain that this layer is as very thick. It was made from the mud at the bottom of the big ocean that covered all of Colorado and Kansas. It is a perfect place to find fossils and bones buried. The city of Ft Collins sits on this layer. If you have ever walked in deep mud that sticks to your shoes and weighs a ton, you have walked on what was the bottom of this ancient ocean. Time past is getting closer to time present! (Bag #6) At last the Rocky Mountains we can see in time present appear! About 66 Million years ago the Rocky Mountains were uplifted and formed. Bag 6 players remove the foam model and as one gently pushes it from each end the other makes a fist and raises it up under the foam to demonstrate the uplift. The Timekeeper (66 mya) and the Historian (p. 17/18) circulate. Students use their hand to trace the uplifted layers on their worksheet. They move their fingers from right to left toward the mountains showing that each layer is now tipped up. This is a repeat of the original demonstration of uplift done with their hands. As they do this you remind them that this is second time the mountains have uplifted. The first mountains/ancestral Rockies eroded away and now they are rising again. These Rockies are the big mountains we see in Estes Park or Rocky Mountain Nat Park. Point out boxes 1-4 on the work pages to show the process. Reinforce how slowly this happens. Colorado is warm and rainy with lots of plant life. But as we get closer to time present, the temperatures drop and Colorado becomes much colder. Glaciers form in the tallest mountains. The big mammals such as Woolly Mammoth, Mastadons and huge Buffalo roam Colorado. Finally we have arrived at time present! The Timekeeper (today) and Historian (p. 31) circulate. This is the Colorado we see today in time present, but we now know that it is not what Colorado has always looked like in time past. And we now know that the glaciers, rivers, and winds are still at work eroding the mountains we see. Point out box 5 and the top edge of the layers they have been filling in on the work page. Students can trace the rough edge with their finger or pencil. As they do explain that nature has been at work here eroding away the softer rocks and layers. Gently pull the cut blue towel down from their knees towards Colorado s feet. (AT PINERIDGE) This is why as we stand here looking up at the mountain ridge we are looking at the Dakota layer and the Pierre Shale layer is behind and under the city of Ft Collins. Point out the little stick figure facing the mountains on the worksheet. You can also point out the cut in the hogback ridge that exposes the layers and is clearly visible from the parking lot. Conclusion: 1. What will Colorado look like in time future? Allow for a few speculations. Be sure to ask, Do you think these mountains will be here forever? Why?

5 2. The way Colorado looks today is not how it has always looked. Today we learned that what we see in time present is the work of time past and the beginning of time future. So Colorado is your true BFF! Let s take care of all Colorado s layers! *This lesson was written by Zoe Whyman, Sue Kenney, Susan Schafer and Dolores Daniels of the City of Fort Collins Natural Areas Department, and with the guidance of Dr. Lynn Rubright, adapted from the Denver Museum of Nature and Science s Ancient Denver s project. We extend our sincere thanks to all for their support.

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