18.104.22.168 Tectonic Plates
Recognize that the Earth is composed of layers, and describe the properties of the layers, including the lithosphere, mantle and core.
Correlate the distribution of ocean trenches, mid-ocean ridges and mountain ranges to volcanic and seismic activity.
Recognize that major geological events, such as earthquakes, volcanic eruptions and mountain building, result from the slow movement of tectonic plates.
MN Standard in Lay Terms
The surface of the earth is broken up into pieces called plates. When these plates move together, apart, or alongside each other, the result is many of the landforms we see at the surface and many of the geologic events we experience. Geologic events such as earthquakes have helped scientists learn about the layers of the earth.
To fully reach this standard, it is essential that students understand the connections between the benchmarks. The properties of the different layers of the earth cause plate movement at the surface. This movement results in geologic events and the creation of landforms at the plate boundaries.
MN Standard Benchmarks
22.214.171.124.1 Recognize that the earth is composed of layers, and describe the properties of the layers, including the lithosphere, mantle and core.
126.96.36.199.2 Correlate the distribution of ocean trenches, mid-ocean ridges and mountain ranges to volcanic and seismic activity.
188.8.131.52.3 Recognize that major geological events, such as earthquakes, volcanic eruptions and mountain building, result from the slow movement of tectonic plates.
"With such wisdom has nature ordered things in the economy of this world, that the destruction of one continent is not brought about without the renovation of the earth in the production of another." - James Hutton
- NSES Standards:
The solid earth is layered with a lithosphere; hot, convecting mantle; and dense, metallic core.
Lithospheric plates on the scales of continents and oceans constantly move at rates of centimeters per year in response to movements in the mantle. Major geological events, such as earthquakes, volcanic eruptions, and mountain building, result from these plate motions.
Some changes in the solid earth can be described as the "rock cycle." Old rocks at the earth's surface weather, forming sediments that are buried, then compacted, heated, and often recrystallized into new rock. Eventually, those new rocks may be brought to the surface by the forces that drive plate motions, and the rock cycle continues.
The earth processes we see today, including erosion, movement of lithospheric plates, and changes in atmospheric composition, are similar to those that occurred in the past. earth history is also influenced by occasional catastrophes, such as the impact of an asteroid or comet.
- AAAS Atlas:
The Physical Setting: Changes in the Earth's Surface
Chapter 4B: By the end of the 8th grade, students should know that
The earth is mostly rock. Three-fourths of the earth's surface is covered by a relatively thin layer of water (some of it frozen), and the entire planet is surrounded by a relatively thin layer of air. 4B/M2ab*
Everything on or anywhere near the earth is pulled toward the earth's center by gravitational force. 4B/M3
Chapter 4C: By the end of the 8th grade, students should know that
The interior of the earth is hot. Heat flow and movement of material within the earth cause earthquakes and volcanic eruptions and create mountains and ocean basins. Gas and dust from large volcanoes can change the atmosphere. 4C/M1
Some changes in the earth's surface are abrupt (such as earthquakes and volcanic eruptions) while other changes happen very slowly (such as uplift and wearing down of mountains). 4C/M2a
Sedimentary rock buried deep enough may be re-formed by pressure and heat, perhaps melting and recrystallizing into different kinds of rock. These re-formed rock layers may be forced up again to become land surface and even mountains. Subsequently, this new rock too will erode. Rock bears evidence of the minerals, temperatures, and forces that created it. 4C/M4
Matching coastlines and similarities in rock types and life forms suggest that today's continents are separated parts of what was long ago a single continent. 4C/M9** (SFAA)
The outer layer of the earth-including both the continents and the ocean basins-consists of separate plates. 4C/M11** (BSL)
The earth's plates sit on a dense, hot, somewhat melted layer of the earth. The plates move very slowly, pressing against one another in some places and pulling apart in other places, sometimes scraping alongside each other as they do. Mountains form as two continental plates, or an ocean plate and a continental plate, press together. 4C/M12** (BSL)
There are worldwide patterns to major geological events (such as earthquakes, volcanic eruptions, and mountain building) that coincide with plate boundaries. 4C/M13** (BSL)
- Tectonic plates stack like dinner plates in a kitchen cabinet.
- A continent is a plate; plates are the same shape as the continents.
- The plates are somehow "down there"-not really related to Earth's surface.
- The plates are under the oceans, but do not include the continents.
- Continents move by somehow floating across oceans.
- The continents float around on something-molten rock or water-like very large ships.
- Since the super-continent Pangaea split up ~200 million years ago, the continents have remained in essentially the same positions.
- Earthquakes caused Pangaea to break apart.
- Continents (and plates) can never join together or split and become smaller.
- Plates are the same size and shape now as they've always been.
- After Pangaea broke apart, the continents moved around to the other side of Earth and will bump back into one another. (This bumping will lead to earthquakes.)
- When two plates come together, non-volcanic mountains always form.
Ford, B. and Taylor, M. (2006). Investigating Students' Ideas about Plate Tectonics. Science Scope. Vol 30(1). pp 38-41. (note: NSTA members can access this article on line through the NSTA Journal Archives at nsta.org)
Students in Mr. G's classroom have been learning about plate tectonics. They have learned how Wegner put together his ideas and the evidence on the seafloor that was found much later. The students have watched many animations of plate boundaries, have drawn their own examples in their notebooks, and have worked with physical models. All of the students can model the movements of plates moving toward each other, away from each other, and alongside each other and use the proper terms to describe these boundaries. The teacher draws the students' attention to the projection of the earth on the screen. Google Earth is on display, and he sets the earth spinning. He also points out the raised relief map on the wall. He challenges students to work together looking at these resources to identify several examples of each type of boundary and to record the evidence that they see on the map to share. The students quickly get into groups around the map and the projected image. Students start pointing to locations on the map and words like "volcanic mountain chain" and "subduction zone" can be heard. Soon the students have their notebooks out recording their information. Mr. G circulates, correcting misinformation that he hears by asking questions of the groups. He ensures that the students are on the right track and that they are looking for examples of each type. The students are excited that the information they have been learning has helped them to identify these features on the earth's surface. When they have completed their task, they return to their seats eager to share their findings and explanations. (Hoffmann, 2011)
Suggested Labs and Activities
This companion site to the PBS series "Savage Earth" is an amazing resource for animations, additional information, that would be excellent supplements to classroom instruction. (184.108.40.206.1. 220.127.116.11.2. 18.104.22.168.3.)
This very scripted lesson plan from NASA focuses on the link between locations of volcanism and plate boundaries. This is a common connection, but the resource has great focus questions, highlights the big ideas, and includes specific student misconceptions. It is 5th in a series of lessons. (22.214.171.124.3)
From the Incorporated Research Institutions for Seismology, this website has background information, animations, and lesson ideas. Some of the vocabulary used may be a little advanced for 8th grade, but could be easily adapted. (126.96.36.199.1. 188.8.131.52.2. 184.108.40.206.3.)
This University of Michigan site has very good explanations for teacher background knowledge but may be difficult for students to understand on their own. However, the many different types of maps, video, and images would be very useful supplements to classroom instruction. (220.127.116.11.1. 18.104.22.168.2. 22.214.171.124.3.)
Drawing representations of the earth's interior, the plate boundaries and the associated landforms that are created helps students to process and retain what they have learned. This is not a fully formed lesson plan, but a good reminder and starting point. (126.96.36.199.1. 188.8.131.52.2. 184.108.40.206.3.)
Developing Student Understanding (From NESE)
A major goal of science in the middle grades is for students to develop an understanding of earth and the solar system as a set of closely coupled systems. The idea of systems provides a framework in which students can investigate the four major interacting components of the earth system-geosphere (crust, mantle, and core), hydrosphere (water), atmosphere (air), and the biosphere (the realm of all living things). In this holistic approach to studying the planet, physical, chemical, and biological processes act within and among the four components on a wide range of time scales to change continuously earth's crust, oceans, atmosphere, and living organisms. Students can investigate the water and rock cycles as introductory examples of geophysical and geochemical cycles. Their study of earth's history provides some evidence about co-evolution of the planet's main features-the distribution of land and sea, features of the crust, the composition of the atmosphere, global climate, and populations of living organisms in the biosphere.
By plotting the locations of volcanoes and earthquakes, students can see a pattern of geological activity. Earth has an outermost rigid shell called the lithosphere. It is made up of the crust and part of the upper mantle. It is broken into about a dozen rigid plates that move without deforming, except at boundaries where they collide. Those plates range in thickness from a few to more than 100 kilometers. Ocean floors are the tops of thin oceanic plates that spread outward from midocean rift zones; land surfaces are the tops of thicker, less-dense continental plates.
Because students do not have direct contact with most of these phenomena and the long-term nature of the processes, some explanations of moving plates and the evolution of life must be reserved for late in grades 5-8. As students mature, the concept of evaporation can be reasonably well understood as the conservation of matter combined with a primitive idea of particles and the idea that air is real. Condensation is less well understood and requires extensive observation and instruction to complete an understanding of the water cycle
Free NSTA online interactive modules to increase teacher background knowledge and understanding of plate tectonics, beginning with the structure of the Earth and progressing through the results of plate interactions.
- core - the innermost layer of the earth composed mostly of iron and nickel; consists of a liquid outer core surrounding a solid inner core
- earthquake - a sudden release of energy in the earth's lithosphere that creates seismic waves
- fault - a break in the earth's lithosphere along which there is movement
- lithosphere - the rigid, rocky outer layer of the Earth
- mantle - the plastic layer of the Earth below the lithosphere; pressure and temperature increase with depth
- mid-ocean ridges - long areas of uplift that form in the oceans where two plates are moving apart
- mountain ranges - chains of mountains often formed by plates moving toward each other
- ocean trenches - deep trenches in the oceans the form along subduction zones
- plate boundary - where plates meet and interact creating a variety of landforms and causing geologic events
- subduction - where one plate moves below another plate; often results in the formation of a trench
- tectonic plates - rigid sections of the Earth's lithosphere that slowly move on the Earth's plastic mantle
- Volcanic Eruptions - lava and volcanic ash moving onto the earth's surface, resulting in the formation of new igneous rock
A PBS site which includes information about how scientists developed the Theory of Plate Tectonics. Also includes interactive plate boundary tools and explanations of what happens at each type of boundary. (220.127.116.11.1. 18.104.22.168.2. 22.214.171.124.3.)
This interactive Annenberg Foundation site starts with the layers of the Earth, includes a brief overview of Wegener's contributions in introducing plate tectonics and then addresses plate boundaries. Could be used by students independently or as a supplement to classroom instruction. (126.96.36.199.1. 188.8.131.52.2. 184.108.40.206.3.)
This website from the Scripps Institution of Oceanography goes through the basic ideas of plate tectonics and the landforms associated with plate boundaries. This website could be easily used independently by students to research or reinforce concepts. (220.127.116.11.1. 18.104.22.168.2. 22.214.171.124.3.)
The National Earth Science Teachers Association site Windows to the Universe is packed with information, animations, links and other resources covering these and many other topics. A very indepth and resource with information written in a way that easy to understand at both a teacher and student level.
Maps are used extensively in the study of plate tectonics
Tectonic events affect all aspects of geography
Assessment of Students
What landforms would you expect to see at each of the different plate boundary types?
Looking at USGS data, what do you notice about the distribution of volcanoes and earthquakes on the earth?
Explain how volcanoes, earthquakes, and plate boundaries are related.
Looking at a raised relief map, identify mid-ocean ridges, trenches, volcanic mountain ranges, volcanic island arcs, and mountain ranges formed by plate interactions.
Assessment of Teachers
Do I know how to use Google Earth teach this standard effectivley?
What news events can add insight & "real-life" examples of plate tectonics? How could I use these events to improve student understanding?
What is the evidence for the theory of plate tectonics?
How does the interaction of the layers of the earth result in the plate movement we experience at the surface? What are some ways to model these interactions?
What are some good examples on earth of each of the different landforms that results from tectonic activity?
According to Lee & Buxton (2010), a couple of approaches are useful for assisting English Language Learners (ELLs): teach content while fostering language development and draw on the so-called "funds of knowledge", which are students' personal experiences from home or community. For additional details on this see the original NSTA News posting and the official NSTA position statement.
Lee, O., & Buxton, C.A. (2010, April). NSTA Report: Teaching science to English language learners.
English Language Learners. Official NSTA Position Statement.
Students who have mastered the concepts may be challenged to investigate tectonic plate activity in Minnesota's past. There are many sources of information about Minnesota's geologic past and most of it is written for a higher level than 8th grade, so students may need some assistance in understanding some of the ideas to piece together the pre-glacial story of Minnesota.
There is a lot of vocabulary that is necessary for understanding this standard. Many of the terms can be represented in picture form as well, which helps all students to learn and make connections between what they know and new vocabulary.
Students should be encouraged to show their understanding in different ways. Using hands to demonstrate the movement of the different boundary types, explaining the concepts to others verbally, showing understanding through drawings or models are all possibilities with this standard.
The websites presented here are at different levels of complexity. Unfortunately plate tectonics is not addressed in many books written at lower reading levels, but the earth's structure and the geologic events are. A librarian could be helpful in locating these resources. The link between these resources and the plate tectonics concepts would need to be made in other ways by the classroom teacher.
Plate tectonics and the structure of the earth are very visual topics. During a unit covering these topics, there should be a variety of representations of plate boundaries, physical models, raised relief maps, satellite images, etc. It is likely that there will be projections of animations regularly as these concepts involve steady slow movement and may be difficult for students to understand through static images and descriptions alone. Additionally, students may be engaged in drawing their own representations and constructing models.
For many parents, plate tectonics may not be something that they learned about in school. Ask that students teach their parents about this theory.