Earth's Tectonic Plates

1. Period 1: Presentation slides 1-9 (the Antarctic forest phenomenon, targets, Ortelius and Wegener, the four lines of evidence, why drift was set aside, the 1926 debate). W1 phenomenon worksheet as the opener; W2 vocabulary relationships to close.
2. Period 2: Lab 1, the landmass-fit mystery (one session): groups fit simplified southern landmass shapes by outline, then by fossil, rock and glacial evidence, and score each arrangement. W8 collaborative evidence jigsaw can replace or follow the lab.
3. Period 3: Slides 10-15 (seismic waves and the lithosphere, earthquake and volcano belts, sonar and Marie Tharp's maps, the four seafloor structures). W3 reading passage for homework or in class; W4 diagram interpretation of a ridge-to-trench cross-section.
4. Period 4: Lab 2, the paper seafloor (one session): groups build a spreading ridge from paper strips, mark age bands, measure and graph distance against model age, and test an uneven pull. Slide 16 (the seafloor spreading prediction) opens the period.
5. Period 5: Slides 17-21 (drill ship criteria and constraints, the simulated core-age task, the rate check, from hypothesis to theory, the timeline). Lab 3, the drill-core data decision (one session), or W5 data worksheet if time is short.
6. Period 6: Slides 22-24 (boundary types and rates, the Pinnacles connection, the 'why is Earth not growing' discussion). W6 CER on evidence for moving continents as the written assessment; W7 misconception repair; W9 drill-ship transfer task for the engineering strand.
7. Period 7: Slides 25-27 (misconception, synthesis, exit). W10 mastery as the quiz. Reteach from the exit-ticket piles.

Materials overview: No chemicals, no heat, no sharp tools beyond scissors. Lab 1 uses card stock, colored dot stickers and a printed evidence key. Lab 2 uses adding-machine paper, a cardboard sheet with slots, markers and rulers. Lab 3 is paper and calculator only. A wall map or globe and a projected plate map help every period. If a 'fossil' prop is wanted for the phenomenon, a photo of Glossopteris leaves and of a Lystrosaurus skull works; no specimens are needed.

• Multilingual learners: Pre-teach six anchor terms (hypothesis, evidence, plate, ridge, trench, spreading) with a picture card set; let students label the Lab 1 sketch and the Lab 2 cross-section in their home language first; pair during the evidence-scoring so each piece of evidence is read aloud and explained before it is scored.
• Students who need more support: Provide the Lab 3 rate table with the first row worked, a graph with axes already scaled, sentence frames for the CER ('Fossils of ___ are found in ___ and ___, which shows ___ because ___'), and a two-column criteria/constraints sort with a word bank.
• Students ready for extension: Ask them to explain why the Atlantic's oldest seafloor lies beside the continents while the Pacific's lies at trenches, to estimate when the South Atlantic began to open from a rate and a half-width, or to research how GPS measures plate motion today and compare it with rates computed from seafloor ages.
• Students who need movement or alternative output: Run the timeline as a floor line with students holding event cards; let the Lab 2 model be demonstrated live to the class instead of written up; allow the synthesis to be a 60-second spoken explanation or a labeled poster of the evidence.
• Students with limited fine-motor control or low vision: Use large card pieces with raised sticker dots for evidence in Lab 1; let a partner pull the paper strips in Lab 2 while the student calls the tick and reads the ruler with a hand lens; provide the Lab 3 dataset in large print and accept rates computed for three cores rather than all six.

• Mantle state: the textbook says the mantle below the lithosphere 'is capable of flowing' (pp. 206, 217) without saying it is solid. Teach that the mantle is solid rock that creeps very slowly; it is not liquid magma, and plates do not float on a liquid.
• Driving forces: the book presents mantle convection, seafloor spreading and subduction as the three processes that drive plate motion (p. 215). Current research treats the pull of old, dense plates sinking at trenches ('slab pull') as the strongest force, with mantle flow and ridge push also contributing, and the details are still debated. Mention this only in teacher notes; MS-ESS2-3 does not assess mechanisms.
• Oldest seafloor location: p. 213 lists 'the oldest rocks at the trenches'. That holds where trenches exist; in the Atlantic the oldest seafloor lies against the continental shelves, as the book's own Figure 4B shows. Teach 'older with distance from the ridge'.
• Glossopteris: the book calls it 'a fern that grew only in warm climates' and uses it to argue the continents were nearer the equator (p. 205). It was an extinct seed plant (a 'seed fern', not a true fern), and Antarctic fossil wood shows it grew at polar latitudes in a cool, strongly seasonal climate. Use its fossils only as evidence that the southern continents were joined and that Antarctica's climate has changed.
• Lystrosaurus: the book says its fossils are found 'only' in Antarctica, southeastern Africa and India (p. 205). They are also found in China and Russia. Say 'found in' rather than 'only in'.
• Mesosaurus: the book says it 'lived only in fresh water' (p. 205). Its habitat is debated (fresh, brackish or salty lagoons). The argument needs only that it was a small shallow-water reptile unable to cross an open ocean.
• San Andreas rate: p. 217 gives about 5 millimeters per year. USGS gives about 5 centimeters (50 mm) per year for the Pacific and North American plates' relative motion; the printed figure appears to be a unit slip. The deck uses about 5 cm per year across the whole plate boundary and notes that the San Andreas Fault itself takes only part of that motion.
• Nazca convergence: p. 216 gives 70-100 mm per year. USGS gives about 80 mm per year in the south falling to about 65 mm per year in the north; the deck uses 65-80 mm per year.
• Red Sea: p. 216 gives 15-15.7 mm per year. GPS studies report about 15 mm per year of opening for the southern Red Sea; the deck says 'about 15 mm per year in the south'.
• Glomar Challenger: the book says scientists 'redesigned an existing drill ship' (p. 210). The ship was newly built (keel laid 1967, launched March 1968) for the Deep Sea Drilling Project. The South Atlantic transect that confirmed the age pattern was Leg 3 (late 1968 to early 1969), which drilled 17 holes at 10 sites, not the ship's very first voyage.
• JOIDES Resolution: p. 211 says the ship 'is still exploring the seafloor today'. Its final scientific expedition sailed in 2024; teach it in the past tense. Its site and depth totals in the book describe an earlier date.
• Deepest drilling: p. 206 gives 12,262 m as the deepest hole (the Kola borehole, on land). No drill has gone through the full thickness of the crust into the mantle, but in 2023 the JOIDES Resolution recovered more than a kilometer of mantle rock from a place on the Mid-Atlantic Ridge where mantle rock is exposed at the seafloor.
• Number of plates: the book says there are 15 major plates (p. 214). The count depends on how plates are grouped; sources list seven or eight very large plates, about a dozen once the mid-sized ones are counted, plus many smaller ones. Say 'about a dozen major plates and many smaller ones' and never assess a count.
• Seismic wave speed: p. 206 says waves travel faster through denser rock. Speed depends on stiffness as well as density; with stiffness fixed, denser rock actually slows the waves. Teach only that waves change speed and direction when the rock they pass through changes.
• Fracture zones: p. 208 says the two sides of a fracture zone move in opposite directions. That is true only on the active stretch between offset ridge segments (a transform fault); beyond that, fracture zones are mostly inactive scars.
• Source of magma at subduction zones: p. 216 says part of the sinking plate melts. Scientists debate whether the melting is in the sinking plate, the mantle above it, or both; say 'melting deep below feeds the volcanoes' without naming which rock melts.
• San Andreas behavior: p. 217 says transform motion builds stress until sudden slip. The locked sections of the fault behave this way; a central section from San Juan Bautista to Parkfield creeps steadily, with many small earthquakes but no large ones; Parkfield itself is a transition zone.
• Wegener's dates: the book says 1912 (pp. 204, 214) and a photo caption says 1915 (p. 205). Both are right: he presented the idea in January 1912 and published his book The Origin of Continents and Oceans in 1915. Pangaea assembled about 300 million years ago and began to break apart about 200 million years ago.
• Appalachian-Atlas match: the old rock belt that continues the Appalachians is best seen in Morocco's Anti-Atlas; the High Atlas gained much of its height far later. 'One mountain range torn in two' is a simplification; 'matching old rock belts on facing coasts' is accurate.
• Age of plate tectonics: p. 214 says plate motion over 'the past 3 billion years' built today's features. When plate tectonics began is debated, with published estimates ranging from more than 4 billion to less than 1 billion years ago and many near 3 billion. Do not assess a start date.
• Theory wording: p. 214 can read as if a theory is proven and final. Teach that a theory is a well-tested explanation that remains open to refinement; the lesson's own standards box lists 'Scientific Knowledge is Open to Revision in Light of New Evidence'.
• Paleomagnetic stripes: in 1963 Vine and Matthews proposed that magnetic stripes on the seafloor are a record of spreading; ship surveys published in 1965-66 (Vine and Wilson; Pitman and Heirtzler) showed the predicted mirror-image pattern across ridges, a decisive test. The MS-ESS2-3 assessment boundary excludes paleomagnetic anomalies, so the stripes appear only as history (teacher notes, the timeline slide and the W3 passage) and are never assessed.