What causes Earth's surface to change?

This unit builds towards the following NGSS Performance Expectations (PEs): 

• MS-ESS1-4: Construct a scientific explanation based on evidence from rock strata for how the geologic time scale is used to organize Earth’s 4.6-billion-year-old history. 

• MS-ESS2-1: Develop a model to describe the cycling of Earth’s materials and the flow of energy that drives this process.

• MS-ESS2-2: Construct an explanation based on evidence for how geoscience processes have changed Earth’s surface at varying time and spatial scales.
• MS-ESS2-3: Analyze and interpret data on the distribution of fossils and rocks, continental shapes, and seafloor structures to provide evidence of the past plate motions.

ESS1.C: The History of Planet Earth

• The geologic time scale interpreted from rock strata provides a way to organize Earth’s history. Analyses of rock strata and the fossil record provide only relative dates, not an absolute scale. (MS‑ESS1‑4)
• Tectonic processes continually generate new ocean seafloor at ridges and destroy old seafloor at trenches. (HS.ESS1.C GBE) (secondary to MS‑ESS2‑3)

ESS2.A: Earth’s Materials and Systems

• All Earth processes are the result of energy flowing and matter cycling within and among the planet’s systems. This energy is derived from the sun and Earth’s hot interior. The energy that flows and the matter that cycles produce chemical and physical changes in Earth’s materials and living organisms. (MS‑ESS2‑1)
• The planet’s systems interact over scales that range from microscopic to global in size, and they operate over fractions of a second to billions of years. These interactions have shaped Earth’s history and will determine its future. (MS‑ESS2‑2)

ESS2.B: Plate Tectonics and Large-Scale System Interactions

• Maps of ancient land and water patterns, based on investigations of rocks and fossils, make clear how Earth’s plates have moved great distances, collided, and spread apart. (MS‑ESS2‑3)

ESS2.C: The Roles of Water in Earth’s Surface Processes

• Water’s movements—both on land and underground—cause weathering and erosion, which change the land’s surface features and create underground formations. (MS‑ESS2‑2)

While this unit engages students in multiple SEPs across the lesson level performance expectations for all the lessons in the unit, there are four focal practices that this unit targets to support students’ development:

• Developing & Using Models
• Using Mathematics & Computational Thinking
• Constructing Explanations and Designing Solutions
• Engaging in Argument from Evidence

• Cause and Effect
• Scale, Proportion, and Quantity
• Stability and Change

The unit is organized into two main lesson sets, each of which help make progress on a sub-question related to the driving question for the entire unit. Lessons 1-9 focus on developing science ideas behind what causes a mountain to grow and/or move. Lessons 10-13 transition to focusing on what can cause other mountains to change elevation and location. In Lesson 14, students apply what they have figured out about how Earth’s surface changes to explain how a fossil can be found on a mountain top.

This unit exposes students to movement data using different measurements and time scales, and, importantly, the movement of two objects in relationship to one another. Students wrestle with GPS movement data in different directions and also visualizing the depth and breadth of earthquake patterns using a visualization tool. Prerequisite math concepts that may be helpful include:

• CCSS.Math.Content.4.MD.A.1 Know relative sizes of measurement units within one system of units including km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec. Within a single system of measurement, express measurements in a larger unit in terms of a smaller unit. Record measurement equivalents in a two-column table. 
• CCSS.MATH.CONTENT.5.MD.A.1 Convert among different-sized standard measurement units within a given measurement system (e.g., convert 5 cm to 0.05 m), and use these conversions in solving multi-step, real world problems.
• CCSS.Math.Content.5.NBT.A.3 Read, write, and compare decimals to thousandths.
• CCSS.Math.Content.5.NBT.A.4 Use place value understanding to round decimals to any place.
• CCSS.Math.Content.6.RP.A.2 Understand the concept of a unit rate a/b associated with a ratio a:b with b ≠ 0, and use rate language in the context of a ratio relationship. 

It is important to note that this unit is reinforcing some elementary mathematics standards in a new context and using scales at which students may have not considered before; thus, we anticipate that while some of the mathematics in this unit is aligned to upper elementary math development, it may be a new challenging context for students to apply the mathematics ideas.

This is the fourth unit in 6th grade in the OpenSciEd Scope and Sequence. Given this placement, several modifications would need to be made if teaching this unit earlier or later in the middle school curriculum. These include:

• If taught before Unit 6.2 Thermal Energy, students will not have developed ideas about thermal energy being transferred between particles and that particles of a material at a higher temperature transfer energy faster than particles of a material at a lower temperature. This idea is built on in the next unit, Unit 6.3 Weather, Climate & Water Cycling. Prior to lesson 8, students will need support in visualizing what is occurring to particles as temperature changes so they can figure out what happens to solid rock that gets heated to very high temperatures under the surface of Earth. 
• If taught before Unit 6.3 Weather, Climate & Water Cycling, students will not have developed ideas about density in relation to energy being absorbed by particles and then being transferred between particles. Again prior to lesson 8, students will need some experience with what it means at a particle level when one section of material is denser or less dense than another section of material. 

Students will be challenged in this unit to think about processes that occur on very long time scales and also at very large spatial scales. This will likely be the first time they have thought about Earth system processes happening on scales this large–so large they are really hard to even imagine. Students will likely bring with them some knowledge of different geological time periods (e.g., Triassic and Jurassic time = time of the dinosaurs), but it is really not important for them to know the different names and time periods on a geological time scale. This unit challenges students to think conceptually about how long these processes take to occur, but they will not be asked to identify or name time periods. 

To represent these spatial scale ideas students will transition between top-down perspectives and cross-section perspectives to represent movement of the mantle and the plates of Earth’s crust. Some students may readily come to class with a cross-section perspective, but likely many students will need guidance on drawing cross-sections, at least initially. 

Many students may come to the unit with some ideas about “plates” and “plate tectonics.” It is common for students to think that the continents are the plates and they “float” around slowly in the ocean. This unit purposely uses a map with ocean floor topography (called bathymetry) to help students visualize that the bottom of the ocean is part of Earth’s crust too, as the ocean has “plates” that move as well, and many plates include parts of continents and parts of ocean floors.  

Finally, many students may come to the unit thinking the inside of the Earth is liquid lava. This is because all the images they see of hot stuff coming out of the Earth is liquified rock, in the form of lava. In actuality,  the mantle is made of molten rock that is more solid than liquid, but it behaves as a very thick semi-solid, similar to putty. This unit uses fluids to demonstrate convection, but it is important to emphasize to students that the inside of the Earth is not fluid lava. Because  we cannot replicate the movement of solids at really, really high temperatures, we utilize fluids like water and oil, because they show convection at lower temperatures. 

OpenSciEd units are designed to promote equitable access to high-quality science learning experiences for all students. Each unit includes strategies which are integrated throughout the OpenSciEd routines and are intended to increase relevance and provide access to science learning for all students. OpenSciEd units support these equity goals through several specific strategies such as: 1) integrating Universal Design for Learning (UDL) Principles during the unit design process to reduce potential barriers and provide more accessible ways in which students can engage in learning experiences; 2) developing and supporting classroom norms that provide a safe learning culture, 3) supporting classroom discourse to promote students in developing, sharing, and revising their ideas, and 4) specific strategies to supporting emerging multilingual students in science classrooms. 

Many of these strategies are discussed in the teacher guides in sidebar callout boxes titled “Attending to Equity” and subheadings such as “Supporting Emerging Multilingual Learners” or “Supporting Universal Design for Learning.” Other callout boxes with strategies are found as “Additional Guidance,” “Alternate Activity,” and “Key Ideas” and various discussion callouts. Finally, each unit includes the development of a Word Wall as part of students’ routines to “earning” or “encountering” scientific language. 

For more information about each of these different strategies with example artifacts, please see the OpenSciEd Teacher Handbook.

• Dawn Novak, Unit Lead, BSCS Science Learning
• Whitney Smith, Unit Lead, BSCS Science Learning
• Audrey Mohan, Field Test Unit Lead, BSCS Science Learning
• Lindsey Mohan, Writer, BSCS Science Learning
• Ari Jamshidi, Writer, Berkeley
• Karin Klein, Writer, Independent Contractor, BSCS Science Learning
• Tracey Ramirez, Writer, The Charles A. Dana Center, The University of Texas at Austin
• Kirsten Smith, Writer and Pilot Teacher, Pound Middle School, NE
• Abe Lo, Reviewer & PD design, BSCS Science Learning
• Michael Novak, Writer, Reviewer, & Conceptual design, Northwestern University
• Gretchen Brinza, Pilot Teacher, Boulder Valley School District, CO
• Katie Van Horne, Assessment Specialist, Concolor Research
• Matthew Rossi, Unit Advisory Chair, University of Colorado-Boulder
• Paige Kelpine, Advisory Team & Pilot Teacher
• Rachel Poland, Advisory Team, Innovation Middle School, CA

BSCS Science Learning

• Maria Gonzales, Copyeditor, Independent Contractor
• Renee DeVaul, Project Coordinator 
• Valerie Maltese, Marketing Specialist & Project Coordinator
• Chris Moraine, Multimedia Graphic Designer
• Kate Chambers, Multimedia Graphic Designer

An integral component of OpenSciEd’s development process is external validation of alignment to the Next Generation Science Standards by NextGenScience’s Science Peer Review Panel using the EQuIP Rubric for Science. We are proud that this unit has earned the highest score available and has been awarded the NGSS Design Badge. Read the review for this and all of our other units at nextgenscience.org.