The Arizona STEM Acceleration Project
The Law of Superposition
The Law of Superposition
An 8th grade STEM lesson
Jacqueline Kimzey
6/23
Notes for teachers
Notes
This lesson uses the phenomena as an introduction to the formation of earth’s layers in landmarks familiar to students.
List of Materials
Standards
Science:
8.E1U1.6
Analyze and interpret data about the Earth’s geological column to communicate relative ages of rock layers and fossils.
8.E1U3.7
Obtain, evaluate, and communicate information about data and historical patterns to predict natural hazards and other geological events.
Standards
Math:
8.F.B
Use functions to model relationships between quantities.
F.B. 5 Describe qualitatively the functional relationship between two quantities by analyzing a graph (e.g., where the function is increasing or decreasing, linear or nonlinear)
Objective(s):
Day 1: Draw the layers of Red Mountain in color.
Day 2: Students will illustrate how the law of superposition of rock layers explains the relative age of fossils.
Day 3: Students will analyze a graph showing the effect of ocean temperature changes on a marine invertebrate over a period of time.
Agenda (lesson time)
3 Days
Day 1 Explore Earth’s Layers
Students will be sketching the layers of Red Mountain. Provide students with color pencils and a cutout of the mountain to glue in notebook.
Students will investigate the formation of layers and how they determine the age of fossils
Day 2 The Law of Superposition
Provide students with cut outs of fossils and rock strata diagram
Students will determine the position of the earth layer based on their investigation of the fossil record.
Day 3 Graph Analysis
Students will see the functional relationship between time and the percent survivability of a specie population affected by climate change
How do rock layers help us determine the relative age of rocks?
GEOLOGY PHENOMENA
Hands-on Activity Instructions
All the activities should be done in no more than groups of 3
Day 1: Students will go outside with their notebooks and draw the layers of Red Mountain and finish writing I See and Wonder for about 10 min. Once inside they group share what they saw and what they wonder about. Each group writes one See and one Wonder in a post it and place it on the whiteboard for discussion.
Guiding Questions should lead to a discussion on the geologic changes that carved the topography of the area as in: why are there different colors of the earth? what would we find in the darker layers compared to the lighter layers? Could there have been any geologic processes that caused the different colors as in volcanic eruptions? or earthquakes that might have removed some of the dirt or caused some of the earth to move up?What do you think the layers may tell us about the age of the earth?
Red Mountain is a sacred site for the Native population in the valley and a Native guide is required to hike it. This is an important point to discuss since further exploration of this unit involves the Grand Canyon which also includes some sacred sections to the Hopi tribe.
I provided the cutout of the mountain to make it easier for students to only concentrate on the layers. I had my example up on the screen to help those that couldn’t understand what to do. The notebook page was divided as shown.
Draw the lines on the mountain to separate the rock layers
Hands-on Activity Instructions
Day 2
Students will be given tiles (SET A)representing rock layers with fossils to study. They will be told to stack one on top of the other from oldest to youngest. Some videos and reading material will be available to help them draw conclusions of ages. The corrected layering (SET B) will be given after group discussions.
An introduction of index fossils should be given to guide students in their analysis. Set A will begin with the tile with an M at the bottom of the stack since it is the oldest. https://slideplayer.com/slide/4314881/
As students organize their tiles, guiding questions should prompt them to find the index fossil in each layer and why that fossil is important in dating earth layers. Once they have finished stacking set A, set B will be handed out and placed right next to the stack so that they can see the earth layers with the fossils
Video questions:
1. What does the Law of Superposition state?
2. What are fossils? What do fossils show?
3. Why is the fossil record not complete?
4. How do we know that organisms have gone extinct?
5. What does the fossil record provide for us?
Hands-on Activity Instructions
This activity should be done in pairs, maybe 3 at the most.
Day 3
Events as in tectonic activity and climate changes have impacted how the life formed in the earth’s layers. As the earth cooled and heated, it affected the oceans. The AZ topography was shaped by rising and receding oceans.
AZ was once covered by a shallow ocean including the Grand Canyon. On the bottom layers that were formed by sediment deposits are remains of trilobites, brachiopods, and many other marine life that were numerous at that time.
Students will be given a graph showing two lines that represent two varieties of the same specie. Students will be prompted to investigate the lines and place markers with specific information about the environmental conditions. Students will read the information and work together to label the markers on the graph. The 3 questions will guide the students to formulate a picture of how climate change has affected the formation of the stratigraphy of AZ.
Assessment
This is an introductory lesson which should lay a foundation for more complex understanding of how earth forces have impacted the AZ landmarks locally and as famous as the Grand Canyon and the Painted Desert. Students will identify their knowledge of index fossils and the Law of Superposition in these two formatives. https://depedtambayan.net/wp-content/uploads/2021/11/earthscienceforstem_q2_mod12_indexfossils_v2.pdf
#1
#2
Differentiation
Only provide #2 of the two assessments since it requires only identifying and no writing.
Give students additional opportunities to analyse several outcroppings.
Remediation
Extension/Enrichment
Have students read and analyze the stratigraphy of Red Mountain and connect their findings with the fossil stack they developed.