MS-ESS2-3NGSS*ScienceEarth and Space ScienceGrades 6-8
MS-ESS2-3: Fossils, Rocks, Continents and Seafloor as Evidence of Plate Motion
In plain English: MS-ESS2-3 is the NGSS middle school performance expectation that asks students to analyze and interpret data on where fossils and rocks are found, the shapes of the continents and their continental shelves, and seafloor structures such as ridges, fracture zones and trenches, as evidence that Earth's plates have moved. It is usually taught in grade 6, 7 or 8 Earth science.
Analyze and interpret data on the distribution of fossils and rocks, continental shapes, and seafloor structures to provide evidence of the past plate motions.
Clarification Statement: Examples of data include similarities of rock and fossil types on different continents, the shapes of the continents (including continental shelves), and the locations of ocean structures (such as ridges, fracture zones, and trenches).
Assessment Boundary: Paleomagnetic anomalies in oceanic and continental crust are not assessed.
Next Generation Science Standards · Disciplinary Core Idea: Earth's Systems · Official standard
Students analyze four kinds of data that show Earth's surface is not fixed. Earth's rocky outer shell is broken into large pieces called plates, which carry the continents and the ocean floor and move a few centimeters each year. The evidence includes fossils (preserved remains or traces of living things) and rock types that match on continents now separated by oceans, the way the continents fit together like puzzle pieces along the edges of their continental shelves (the shallow, underwater edges of the continents), and structures on the seafloor: mid-ocean ridges (long underwater mountain ranges where plates move apart), fracture zones (long cracks that cross a ridge and offset it into pieces) and trenches (deep, narrow valleys where one plate sinks beneath another). About 200 million years ago, most land was joined in one supercontinent, which scientists call Pangaea, and it has since broken apart.
The NGSS Clarification Statement says: "Examples of data include similarities of rock and fossil types on different continents, the shapes of the continents (including continental shelves), and the locations of ocean structures (such as ridges, fracture zones, and trenches)." The Assessment Boundary says: "Paleomagnetic anomalies in oceanic and continental crust are not assessed." So this page uses fossils, rocks, continent shapes, seafloor depths and the locations of ridges, fracture zones and trenches, and it leaves out magnetic stripes on the seafloor. The fossil and rock facts are real and rounded; the measurements students analyze are invented for teaching and labeled as invented. Students do the practice of analyzing and interpreting data: they compute, graph, compare and write claims supported by the data.
Learning Objectives
By the end of this lesson, students will be able to:
Interpret the distribution of fossils and rock types across continents as evidence that the continents were once joined
Analyze the fit of continents along their coastlines and their continental shelf edges, and explain why the shelf fit is better evidence
Calculate seafloor depths from echo times and identify ridges, fracture zones and trenches as evidence of plates moving apart or together
Combine several lines of data into a claim, evidence and reasoning explanation of past plate motion
Prior Knowledge Required
Students should already be comfortable with:
Reading maps for patterns in Earth's features, such as mountain ranges and ocean floor 4-ESS2-2
What fossils tell us about organisms and environments of long ago 3-LS4-1
Finding a mean and converting centimeters, meters and kilometers
Show a world map and point to the east coast of South America and the west coast of Africa. Give students one minute to look before the question appears.
Warm-Up Prompt
"These two coastlines look like they could fit together. Is a matching shape enough evidence that the continents were once joined? What other evidence would you want to see before you believed it?"
List students' ideas on the board. Many say "the same animals" or "the same rocks." Tell them that today they will analyze those exact kinds of data, plus data from the ocean floor that no one could see until the 1900s.
Direct Instruction15-20 minutes
Four lines of evidence. Fossils and rocks: the same land organisms and the same rock layers appear on continents that are now thousands of kilometers apart (Diagram 1). Continent shapes: the continents fit best along the outer edge of their continental shelves, where the sea floor starts to drop steeply toward the deep ocean, because that edge, not today's coastline, is the real edge of the continent. Seafloor structures: a mid-ocean ridge runs down the middle of the Atlantic Ocean, matching the shape of the coasts on both sides. Fracture zones cross the ridge and run in the direction the plates moved apart; near the equator they line up with the bend in the coasts of Brazil and West Africa. Trenches lie along the edges of some oceans, next to lines of volcanoes. To measure the depth of the ocean floor, ships send a sound pulse down and time its echo: sound travels about 1,500 m/s in seawater, and the pulse goes down and back, so depth = 1,500 × echo time ÷ 2.
Fossils on two continents
Mesosaurus was a small reptile, about 1 m long, that lived in lakes and shallow, slightly salty water about 280 million years ago. Its fossils are found only in southern Africa and eastern South America, which are now separated by the South Atlantic Ocean.
Result: An animal this small could not swim across an ocean thousands of kilometers wide, so the two regions were once joined. If the South Atlantic opened about 130 million years ago at about 4 cm per year: 4 × 130,000,000 = 520,000,000 cm = 5,200 km.
Matching rocks and old glaciers
Folded rocks of the same type and age form the northern Appalachian Mountains in North America and mountains in Scotland and Norway. Separately, glacial deposits (mixed boulders and scratched rock left by ice) about 300 million years old are found in South America, Africa, India, Antarctica and Australia.
Result: Pushed back together, the mountains form one continuous belt. The glacial deposits now sit in places as warm as India, where no ice sheet could form at sea level today; fitted together, the five landmasses form one ice-covered region near the South Pole. Both point to past plate motion.
Continent shapes: coastline or shelf edge?
Invented data: on a classroom map, students fit South America against Africa and measure the gaps at six points. Along the coastlines the gaps are 240, 120, 300, 90, 210 and 120 km. Along the shelf edges they are 40, 20, 60, 30, 50 and 40 km.
Result: Mean coastline gap = 1,080 ÷ 6 = 180 km. Mean shelf-edge gap = 240 ÷ 6 = 40 km. The shelf-edge fit is 4.5 times closer, so the shelf edges, the true edges of the continents, are the better evidence.
Seafloor structure: a mid-ocean ridge
Invented data: a ship crossing the Atlantic records an echo time of 7.4 s over the deep ocean floor and 3.4 s over the ridge in the middle of the ocean.
Result: Deep floor: 1,500 × 7.4 ÷ 2 = 5,550 m. Ridge: 1,500 × 3.4 ÷ 2 = 2,550 m. The ridge rises 3,000 m above the deep floor. A ridge down the middle of an ocean, parallel to both coasts, is where plates move apart and new ocean floor forms.
Seafloor structure: a trench
Invented data, close to the real Mariana Trench in the western Pacific: a ship records an echo time of 14.4 s.
Result: Depth = 1,500 × 14.4 ÷ 2 = 10,800 m, deeper than Mount Everest (about 8,850 m) is tall. Trenches form where two plates move toward each other and one sinks beneath the other.
After each example, ask: "What does this data show by itself? What would we need to see in another kind of data to make the claim stronger?" Stress that no single line of evidence proves plate motion; the case is strong because fossils, rocks, shapes and seafloor all point the same way.
Guided Practice10-15 minutes
Pairs analyze Diagram 1, which shows where three fossils and the 300-million-year-old glacial deposits are found on five landmasses. They use it to test a fit of the southern continents.
For each row of Diagram 1, list the landmasses where the fossil or rock is found.
On scrap paper, sketch the five landmasses pushed together so that each fossil is found in one connected region, not scattered patches.
Glossopteris had seeds too large to be carried across an ocean by wind. Explain why its pattern is strong evidence that the landmasses were joined.
Lystrosaurus fossils have not been confirmed in South America or Australia. Does that disprove the fit? Write one sentence explaining why missing fossils are weaker evidence than found ones.
Independent Practice10-15 minutes
Each student analyzes the invented data below from drill cores east of a mid-ocean ridge. Sediment (mud and the shells of tiny sea organisms) slowly settles on the ocean floor everywhere, at about the same rate.
Independent practice: invented sediment thickness on the ocean floor east of a ridge
Distance from the ridge (km)
0
200
400
600
800
1,000
Sediment thickness (m)
0
30
70
100
135
170
Students graph the data, describe the pattern (the sediment gets thicker, about 17 m for each 100 km) and write a claim, evidence and reasoning statement: the ocean floor far from the ridge has been collecting sediment longer, so it formed at the ridge and has moved away from it. Ask what they would predict for the ocean floor west of the ridge.
Closure5 minutes
Exit ticket: "Name the four kinds of evidence from today. Choose the one you find most convincing and explain why in two sentences." Return to the warm-up list and check which of the students' ideas the data supported.
Differentiation Strategies
For Struggling Students
Give a table to fill in for the four kinds of evidence with columns for "What the data show" and "What it suggests about the plates"
Provide the echo formula on a card and do the first depth together, step by step: multiply by 1,500, then divide by 2
Use pre-cut continent outlines so students can focus on measuring the gaps
For Advanced Students
Ask students to find another pair of continents with matching fossils or rocks and present the data
Have students use the independent practice data to estimate how fast sediment builds up if the floor moves away from the ridge at 2 cm per year
Ask students to research what scientists said against continental drift in the 1920s and which seafloor data later changed their minds
Assessment Guidance
What to Look For
Check that students tie each claim to specific data (a fossil location, a measured gap, a depth) rather than to the puzzle-like look of the map alone. Look for correct echo calculations that divide by 2, and for students who treat ridges and trenches as the same kind of feature. Listen for the idea that several independent kinds of evidence together make the case strong.
02
Classroom Activities
3 Activities
1
Continent Puzzle: Coastline or Shelf Edge?
20 minPairs
Pairs test which outline of a continent gives the better fit. They cut out South America and Africa along the coastline, fit them and measure the gaps, and then repeat with outlines cut along the continental shelf edge. They also mark the fossil and rock data from Diagram 1 to see whether the patterns line up across the fit.
Procedure
Cut out one copy of each continent along the coastline. Fit them together as closely as you can without overlapping and tape them down.
Choose six points along the join, measure each gap with a ruler and convert to kilometers using the map scale.
Cut a second copy of each continent along the shelf edge (the dashed line), fit them and measure the gaps at the same six places.
Shade where Mesosaurus and Glossopteris are found on both fitted pairs. Pass scissors handle first.
Sample Data (invented)
Coastline gaps: 210, 160, 290, 130, 230 and 180 km (mean 200 km). Shelf-edge gaps: 50, 30, 70, 40, 60 and 50 km (mean 50 km).
Discussion Questions
How many times larger is the mean coastline gap than the mean shelf-edge gap in the sample data?
Why might today's coastlines be a poorer guide to the shape of a continent than the shelf edge? Think about sea level and waves.
Did the Mesosaurus regions on the two continents meet when you fitted them? What does that add to the shape evidence?
Modification for Distance Learning
Students trace the outlines on paper at home or drag them on a shared slide, and post a photo of their best fit with their gap measurements.
2
Mapping the Seafloor from Echo Times
25 minPairs
Pairs play the part of a research ship crossing an invented ocean. They convert 12 echo times into depths, plot the depth profile and identify the structures they find, then compare their graph with Diagram 2.
Sample Data (invented)
Station
Distance from west coast (km)
Echo time (s)
1
0
0.2
2
200
0.4
3
400
5.2
4
800
7.0
5
1,200
6.6
6
1,600
5.0
7
1,900
3.2
8
2,200
4.8
9
2,600
6.4
10
3,000
7.2
11
3,300
10.8
12
3,400
2.0
Procedure
Find the depth at each station with depth = 1,500 × echo time ÷ 2.
Plot depth (downward) against distance and connect the points.
Label the continental shelf, the deep ocean floor, the ridge and the trench.
Discussion Questions
At which station is the ocean shallowest away from the coasts, and what structure is there?
Going away from the ridge in both directions, does the ocean floor get shallower or deeper? What could that pattern suggest about how the ocean floor moves?
Station 11 is the deepest point and Station 12 is only 100 km away. What kind of structure is this, and are the plates there moving apart or together?
Challenge Variation
A ship's echo takes 8.0 s, but the ship's computer uses 1,450 m/s instead of 1,500 m/s for the speed of sound. Find both depths and explain how large the error is.
3
Evidence Stations: Building the Case for Moving Plates
20 minGroups of 3-4
Four stations each hold one line of evidence. At each station, groups write what the data show, rate how strongly it supports past plate motion (weak, medium or strong) and give one reason. At the end, each group writes one claim that uses all four stations.
Station Cards
Station 1, fossils: Diagram 1, plus a card saying that Glossopteris seeds were too large to blow across an ocean and that Lystrosaurus lived on land.
Station 2, rocks: a map of the northern Appalachian Mountains and the mountains of Scotland and Norway with matching rock ages, and a map of 300-million-year-old glacial deposits.
Station 3, shapes: the fitted continent outlines from Activity 1.
Station 4, seafloor: a map of the Atlantic Ocean floor showing the ridge in the middle, fracture zones crossing it, and a map of the Pacific showing trenches next to lines of volcanoes.
Discussion Questions
Some scientists once explained matching fossils with "land bridges" that later sank. Which station gives evidence that a land bridge cannot explain?
Which station gives evidence about the direction the plates moved, and how?
Which line of evidence would have been impossible to collect before ships could measure the deep ocean floor?
Modification for Distance Learning
Post each station as a slide. Groups work in breakout rooms and fill in a shared table with their ratings and reasons.
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: Where Three Fossils and Old Glacial Deposits Are Found
Real fossil and rock data, simplified from the classic maps used to support continental drift. Each filled circle means the fossil or deposit is found on that landmass. Lystrosaurus has also been found in parts of Asia outside India. The patterns form connected regions only if the five landmasses are fitted together, as they were in Pangaea.
Diagram 2: Ocean Floor Depths from Echo Times (Invented Data)
The 12 invented echo stations from Activity 2, converted with depth = 1,500 × echo time ÷ 2 and drawn to scale. The depth scale is stretched about 170 times compared with the distance scale, so slopes look much steeper than they are. The ocean floor is shallowest at the ridge and deepens away from it on both sides; the trench lies next to the continent on the east side.
04
Homework Assignment
~30 min
MS-ESS2-3 Homework: Analyzing the Evidence for Plate Motion
Directions: The fossil and rock facts are real and rounded; all measurements are invented for practice. Use depth = 1,500 × echo time ÷ 2 for echo data. Show each calculation with units and end each problem with a claim supported by the data.
Part 1: Fossils and Rocks (Problems 1-2)
Two invented continents, P and Q, are now 3,600 km apart. Fossils of the same land plant, with seeds too heavy to float or blow far, are found in 260-million-year-old rock on both. A belt of 1-billion-year-old rock ends at the coast of P and continues on the facing coast of Q. (a) Write a claim about P and Q. (b) Give two pieces of evidence. (c) If the ocean between them widened at 3 cm per year, how long did it take to reach 3,600 km?
Glacial deposits about 300 million years old are found in India and southern Africa, which are warm today. Coal, which forms from plants that grow in warm, wet swamps, is found in Antarctica. (a) Explain why each fact is hard to explain if the continents never moved. (b) Explain how both facts fit the idea that the continents were once joined and have since moved.
Part 2: Continent Shapes (Problems 3-4)
A student fits two continents on a map. The gaps along the coastlines are 160, 220, 90, 260 and 140 km. The gaps along the shelf edges are 30, 50, 20, 70 and 30 km. (a) Find each mean gap. (b) By what percent does using the shelf edge reduce the mean gap? (c) Explain why the shelf edge is the better outline to use.
The central North Atlantic Ocean is about 5,000 km wide between two matching coasts, and it began to open about 200 million years ago. (a) Find the average rate of opening in centimeters per year. (b) Fingernails grow about 3-4 cm per year. Compare the two rates in one sentence.
Part 3: Seafloor Structures (Problems 5-6)
A ship records these invented echo times at stations 0, 300, 600, 900 and 1,200 km from a coast: 6.8, 4.4, 3.0, 4.6 and 12.0 s. (a) Find the depth at each station. (b) Where is the ridge and where is the trench? (c) At which of these two structures are plates moving apart, and at which are they moving together?
A map of an invented ocean shows a ridge broken into five pieces by fracture zones that all run east-west. A trench and a line of volcanoes lie along the ocean's eastern edge. (a) In which direction did the plates on either side of the ridge move apart? Use the fracture zones as evidence. (b) Explain what is happening at the eastern edge. (c) Which of these features would you look for to test whether an ocean is still widening?
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
Calculations
Means, percents, rates and depths correct with units, including the divide-by-2 step for echoes
Correct method with one calculation or unit error
Interpreting Data
Identifies the pattern in each data set and the feature or event it points to
Describes the data but does not connect it to a feature or event
Claim and Evidence
Claim about past plate motion supported by at least two specific pieces of data
Claim supported by one piece of data or by general statements
Reasoning
Explains why the evidence is hard to explain without moving plates
Reasoning is missing or repeats the evidence
05
Quiz: 20 Questions
Interactive, with answers
Instructions
The fossil and rock facts are real; the measurements are invented for practice. Use depth = 1,500 × echo time ÷ 2 for echo data. Your score updates as you answer, and Reset quiz clears everything so you or your students can try again.
Multiple choice: pick an option to check it. Short answer: write your answer, then reveal the model answer.
0 of 20 answered · 0 correct
Question 1 of 20 · Multiple Choice
Why do scientists fit continents along the edges of their continental shelves instead of along their coastlines?
Answer: B
The continental shelf is part of the continent covered by shallow sea, so its outer edge is where the continent really ends; coastlines move as sea level rises and falls and as waves wear the land. Choice C reverses this: the shelf is continental rock. Choice A is a reason to use coastlines, not a reason to prefer shelves.
Question 2 of 20 · Multiple Choice
Invented data: fossils of the same small freshwater fish are found in 250-million-year-old lake rocks on two continents now 3,000 km apart. Which conclusion do the data best support?
Answer: D
A freshwater fish cannot survive a long trip through salty ocean, so the simplest explanation is that the lakes were on one landmass that later split. Choice A ignores that the fish lived in fresh water. Choice B would need the same species to appear twice by chance, which the data give no reason to think, and choice C has no evidence.
Question 3 of 20 · Multiple Choice
What happens at a mid-ocean ridge?
Answer: A
At a mid-ocean ridge, plates move apart and melted rock rises to form new ocean floor. Choices B and D describe a trench, where plates move together. Choice C describes mountain building where continents collide.
Question 4 of 20 · Multiple Choice
A deep, narrow trench runs along the edge of an ocean, next to a line of volcanoes. What does this suggest about the plates there?
Answer: C
Trenches form where plates move toward each other and one sinks beneath the other; the sinking plate feeds the volcanoes. Choice A describes a ridge. Choice D describes a fault such as the one along a fracture zone, which does not form a deep trench.
Question 5 of 20 · Multiple Choice
Invented data: a ship records an echo time of 5.8 s. How deep is the ocean floor? (Use depth = 1,500 × echo time ÷ 2.)
Answer: B
Depth = 1,500 × 5.8 ÷ 2 = 8,700 ÷ 2 = 4,350 m. Choice A forgets to divide by 2, counting the trip down and back as the depth. Choice C divides by 2 twice. Choice D divides 1,500 by 5.8.
Question 6 of 20 · Multiple Choice
Invented data: an ocean grew to 2,000 km wide over 40 million years. What was its average rate of opening?
Answer: C
2,000 km = 200,000,000 cm, and 200,000,000 ÷ 40,000,000 = 5 cm per year. Choice A uses one zero too many when converting kilometers to centimeters. Choice B gives the rate in meters (0.05 m per year) but labels it centimeters. Choice D divides 2,000 by 40 and drops the "million."
Question 7 of 20 · Multiple Choice
Glacial deposits 300 million years old are found in India, which is warm today. What is the best explanation?
Answer: A
Fitted with the other southern landmasses, India sat in an ice-covered region near the South Pole, and plate motion has since carried it north. Choice B is false, and choice C ignores that the deposits are far older than the Himalaya, which began to rise when India hit Asia. Choice D does not explain scratched rock and unsorted boulders.
Question 8 of 20 · Multiple Choice
Fracture zones cross a mid-ocean ridge and break it into offset pieces. What do the fracture zones show?
Answer: D
Fracture zones run in the direction the plates spread apart, so they record the direction of past motion. Choice C is wrong: the deepest places are trenches, not fracture zones. Choices A and B are not shown by fracture zones.
Question 9 of 20 · Multiple Choice
Invented data: when two continents are fitted along their coastlines, the gaps are 120, 200 and 160 km. Along their shelf edges, the gaps are 20, 50 and 35 km. What is the mean shelf-edge gap?
Answer: B
Mean = (20 + 50 + 35) ÷ 3 = 105 ÷ 3 = 35 km. Choice A is the mean coastline gap. Choice C is the difference between the two means (160 - 35). Choice D is the sum of the shelf gaps, not divided by 3.
Question 10 of 20 · Multiple Choice
Which of these is NOT evidence of past plate motion?
Answer: C
Cities were built by people in the last few thousand years and say nothing about where continents were millions of years ago. Choices A, B and D are the kinds of data named in this standard: rocks, seafloor structures and fossils.
Question 11 of 20 · Multiple Choice
Invented data: a belt of 1.2-billion-year-old rock ends at the east coast of Continent R, and an identical belt begins on the facing west coast of Continent S. What does this suggest?
Answer: A
Matching rock belts that end at facing coasts would have been one belt when the continents were joined. Choice C does not follow: the continents could be on different plates today. Choice D contradicts the data, which say the belts are identical.
Question 12 of 20 · Multiple Choice
Invented echo depths across an ocean, west to east: 5,000, 4,300, 2,600, 4,100 and 5,200 m. What does the pattern show?
Answer: D
The floor is shallowest (2,600 m) in the middle and deepens toward both sides, the shape of a mid-ocean ridge. Choice A reverses it: a trench would be the deepest point. Choice C confuses shallowest with deepest.
Question 13 of 20 · Multiple Choice
Which observation is evidence that plates are moving toward each other along an ocean edge?
Answer: C
A trench with volcanoes beside it marks a place where one plate sinks beneath another as they move together. Choice A shows plates moving apart. Choice B shows the direction of spreading, and choice D forms everywhere on the ocean floor.
Question 14 of 20 · Multiple Choice
Which fossil distribution could be explained without moving continents?
Answer: B
Seabirds fly across oceans, so finding one on many coasts needs no joined continents. Choices A, C and D are organisms that could not cross a wide ocean by themselves, so they need the landmasses to have been joined.
Question 15 of 20 · Short Answer
Invented data: drill cores show 0 m of sediment at a ridge, 60 m at 300 km from it and 150 m at 750 km from it. Describe the pattern and explain what it suggests about the ocean floor.
The sediment gets thicker with distance from the ridge: about 20 m for each 100 km. Sediment settles at about the same rate everywhere, so the thicker sediment far from the ridge has been collecting for longer. That ocean floor is older, which suggests it formed at the ridge and moved away from it.
Question 16 of 20 · Short Answer
Use three different kinds of evidence from this lesson to support the claim that South America and Africa were once joined.
Fossils: Mesosaurus, a small reptile of lakes and shallow water, is found only in eastern South America and southern Africa, and it could not cross an ocean. Rocks: 300-million-year-old glacial deposits are found on both continents and fit into one ice-covered region when the continents are joined. Shapes: the two continents fit closely along their continental shelf edges. Seafloor: the mid-ocean ridge runs down the middle of the Atlantic, parallel to both coasts, where the plates move apart. Any three, each tied to the claim, earn full credit.
Question 17 of 20 · Short Answer
Invented data: a ship records an echo time of 3.8 s at one station and 9.4 s at another. Find both depths and how much deeper the second station is. Which station is more likely near a ridge and which near a trench?
Depths: 1,500 × 3.8 ÷ 2 = 2,850 m and 1,500 × 9.4 ÷ 2 = 7,050 m. The second station is 4,200 m deeper. The shallow station is more likely near a ridge, and the very deep one near a trench.
Question 18 of 20 · Short Answer
A student says, "The continents' coastlines do not fit perfectly, so they were never joined." Use data about continental shelves to respond.
Coastlines are not the true edges of the continents: they change as sea level rises and falls and as waves erode the land. The continental shelf is part of the continent, so its outer edge is the real edge. When the continents are fitted along their shelf edges, the gaps become much smaller (in this lesson's examples, several times smaller), so the imperfect coastline fit does not disprove that they were joined.
Question 19 of 20 · Short Answer
Invented data: a plate moves 6 cm per year. How far does it move in 1 million years? How long would it take to move 1,200 km?
6 cm × 1,000,000 = 6,000,000 cm = 60 km in 1 million years. 1,200 km ÷ 60 km per million years = 20 million years.
Question 20 of 20 · Short Answer
In the early 1900s some scientists explained matching fossils on different continents with land bridges that later sank into the ocean. Give two pieces of evidence from this lesson that land bridges do not explain.
Land bridges could let animals cross, but they do not explain why the continents themselves fit together along their shelf edges, or why rock belts and 300-million-year-old glacial deposits line up only when the continents are joined. They also do not explain the mid-ocean ridge in the middle of the Atlantic, parallel to both coasts, or fracture zones that show the direction the plates moved apart.
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does MS-ESS2-3 mean?
MS-ESS2-3 asks middle school students to analyze and interpret data on fossils and rocks, continent shapes and seafloor structures as evidence that Earth's plates have moved. The code means Middle School, Earth and Space Science, core idea 2 (Earth's Systems), performance expectation 3.
Is MS-ESS2-3 taught in grade 6, 7 or 8?
It depends on the school. MS-ESS2-3 is a middle school standard for grades 6-8, and it usually sits in an Earth science unit on plate tectonics, often after MS-ESS2-1 (the rock cycle) and MS-ESS2-2 (surface processes).
Which fossils show that the continents moved?
Classic examples are Mesosaurus, a small reptile found only in South America and southern Africa; Glossopteris, a seed fern found on all the southern continents and India; and Lystrosaurus, a land animal found in Africa, India and Antarctica. None of them could cross a wide ocean, so the landmasses must have been joined.
What is the assessment boundary for MS-ESS2-3?
The official Assessment Boundary says paleomagnetic anomalies in oceanic and continental crust are not assessed. Magnetic stripes on the seafloor are left out of this lesson; students use fossils, rocks, continent shapes and the locations of ridges, fracture zones and trenches instead.
Why do the continents fit better at the continental shelf?
Because the shelf edge is the real edge of the continent. Today's coastlines depend on sea level, which has risen and fallen many times, and on waves and rivers that reshape the shore. Fitting along the outer edge of the shelves leaves much smaller gaps and overlaps.
What seafloor structures are evidence of plate motion?
The Clarification Statement names ridges, fracture zones and trenches. Mid-ocean ridges mark where plates move apart, fracture zones cross the ridges in the direction of spreading, and trenches mark where one plate sinks beneath another. Their locations, not only their shapes, are the evidence.
How fast do plates move?
Plates move about 2-10 cm per year, about as fast as fingernails grow. That seems slow, but over millions of years it adds up to thousands of kilometers, enough to open an ocean.
What is the difference between continental drift and plate tectonics?
Continental drift is the idea, put forward by Alfred Wegener in 1912, that the continents have moved. He used fossils, rocks and continent shapes but could not explain how they moved. Plate tectonics, developed in the 1960s after the seafloor was mapped, explains that whole plates, carrying both continents and ocean floor, move.
How does MS-ESS2-3 connect to fossils and the geologic time scale?
MS-LS4-1 asks students to read patterns in the fossil record, and MS-ESS1-4 uses rock layers to organize Earth's history. MS-ESS2-3 uses the same fossils and rock ages, but asks where they are found today to show how the continents have moved.
What comes after MS-ESS2-3 in high school?
HS-ESS1-5 asks students to evaluate evidence of past and current plate movements and the theory of plate tectonics to explain the ages of crustal rocks. HS-ESS2-1 asks how internal and surface processes form landforms on continents and the ocean floor.
07
Related Standards
6 standards
These standards connect to MS-ESS2-3: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
4-ESS2-2Prerequisite
Analyze and interpret data from maps to describe patterns of Earth's features
Lesson coming soon
3-LS4-1Prerequisite
Analyze fossil data for evidence of organisms and environments of long ago
Lesson coming soon
Alongside
MS-ESS1-4Parallel
Explain from rock strata how the geologic time scale organizes Earth's history
NGSS is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it.
