Earth and Space Science · California Grade 8

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.

Clarification statement: Emphasis is on how analyses of rock formations and the fossils they contain are used to establish relative ages of major events in Earth’s history. Examples of Earth’s major events could range from being very recent (such as the last Ice Age or the earliest fossils of homo sapiens) to very old (such as the formation of Earth or the earliest evidence of life). Examples can include the formation of mountain chains and ocean basins, the evolution or extinction of particular living organisms, or significant volcanic eruptions.

Assessment boundary: Assessment does not include recalling the names of specific periods or epochs and events within them.

Source: California Department of Education, NGSS Preferred Integrated Course Model, Grade 8 (accessed 2026-10-18)

Chapters

Chapter 8: Investigating Rock Stratapractice

In California's Preferred Integrated model this PE belongs to Grade 8, so a seventh-grade class using this textbook is meeting it early; label it as a Grade 8 standard on any report. The lesson teaches the relative-dating rules and fossil succession that the PE's clarification names as the evidence base, and Lab 2 and W6 have students construct an explanation of event order from strata evidence, which is the first half of the PE. The organizing role of the geologic time scale itself is built in Lesson 9, and the assessment boundary (no recall of period or epoch names) is respected throughout.

Chapter 9: Reconstructing Earth's Historyassesses

This is a California Grade 8 performance expectation in the Preferred Integrated sequence, so in a Grade 7 class it is an early encounter with the idea, not the year's assessed standard. Even so, Lab 2 asks students to build a composite rock sequence from three sites and locate the levels where fossils change, and Lab 2, W6 and W10 ask them to explain in writing how such strata evidence organizes Earth's history, which is evidence toward the PE as written. In line with the assessment boundary, no task asks students to recall the names of periods or epochs.

Worksheets (20)

Chapter	Worksheet	Role	How it connects
Ch. 8	W1 · The Sea Cliff That Keeps a Diary Phenomenon exploration	practice	MS-ESS1-4 sits in California Grade 8 in the Preferred Integrated model; this Grade 7 lesson previews it. Students begin building explanations from the order and features of rock layers, which is the evidence base the PE asks for.
Ch. 8	W2 · Rules, Features and Clocks: Sorting the Language of Strata Vocabulary in action	supports	MS-ESS1-4 is a California Grade 8 performance expectation that this Grade 7 lesson previews. Commanding the names of the dating rules is background for constructing the explanations from rock strata that the PE calls for.
Ch. 8	W3 · Four People Who Learned to Tell Time in Stone Reading with evidence	supports	MS-ESS1-4 belongs to California Grade 8 in the Preferred Integrated model; this lesson previews it in Grade 7. The passage gives the history and logic behind reading rock strata, which is background for constructing explanations from them rather than evidence toward the PE itself.
Ch. 8	W4 · Reading the Pine Hollow Road Cut: Eight Events in Stone Diagrams and models	practice	MS-ESS1-4 is placed in California Grade 8; this Grade 7 lesson previews it. Ordering the events in a cross-section from the arrangement of its layers and cutting features is the core practice of reading rock strata that the PE's explanation rests on.
Ch. 8	W5 · Half-Lives and Ash Layers: Putting Years on a Cliff Data and graphing	practice	MS-ESS1-4 is a California Grade 8 performance expectation that this Grade 7 lesson previews. Calculating ages from half-lives and using them to bracket sedimentary layers is how relative order gets tied to Earth's 4.6-billion-year history.
Ch. 8	W6 · Two Road Cuts, One Story? A Claim-Evidence-Reasoning Case Claim, evidence, reasoning	practice	MS-ESS1-4 sits in California Grade 8; this Grade 7 lesson previews it. Writing a CER that matches layers across two sites by their fossils is exactly the kind of evidence-based explanation from rock strata the PE describes, at a smaller scale.
Ch. 8	W7 · Fixing Dev's Field Report: Six Errors About Rock Layers Error analysis	practice	MS-ESS1-4 is placed in California Grade 8 and this Grade 7 lesson previews it. Diagnosing wrong uses of superposition, cross-cutting, fossil matching and half-lives sharpens the reasoning the PE's explanations depend on.
Ch. 8	W8 · Tinker Creek Canyon Jigsaw: Twelve Clues, One Timeline Collaborative investigation	practice	MS-ESS1-4 is a California Grade 8 performance expectation; this Grade 7 lesson previews it. Building a canyon's event timeline from layered, cut and dated evidence is the explanation-from-strata work the PE calls for, done collaboratively.
Ch. 8	W9 · Where Can the Gym Go? Reading a Fault Trench Before Building Transfer and design	practice	MS-ESS1-4 is a California Grade 8 performance expectation that this Grade 7 lesson previews. Reading which sediment layers a fault breaks and which lie across it unbroken is relative dating applied to a real engineering question.
Ch. 8	W10 · Rock Strata Check-Up: Twelve Items and a Synthesis Retrieval and mastery check	practice	MS-ESS1-4 is placed in California Grade 8; this Grade 7 lesson previews it. The items check the reasoning from rock strata and the half-life arithmetic that the PE's explanation uses; no period or epoch names are asked, in keeping with the assessment boundary.
Ch. 9	W1 · The Oldest Rocks on Earth Did Not Form on Earth Phenomenon exploration	practice	MS-ESS1-4 is a California Grade 8 performance expectation (geologic time from rock strata); this Grade 7 lesson previews it. Students begin reasoning about why Earth's own rocks cannot record its first half-billion years, the problem the geologic time scale has to solve.
Ch. 9	W2 · Nested Boxes and Big Numbers: The Language of Deep Time Vocabulary in action	supports	MS-ESS1-4 is a California Grade 8 performance expectation. Knowing how the time scale's units nest, how its labels are read, and the difference between relative and absolute dating is background students need before they can explain how the scale organizes Earth's history. The PE's assessment boundary excludes recalling period and epoch names, so q1 is practice with a word bank, not assessment.
Ch. 9	W3 · Three Cliffs, One Story: How Short Rock Records Become Deep Time Reading with evidence	practice	MS-ESS1-4 is a California Grade 8 performance expectation. This passage lays out the chain from rock layers to relative order, to matched sections, to pinned absolute ages, to fossil-defined boundaries; the questions ask students to reconstruct that explanation from evidence in the text, which is the reasoning the PE asks for.
Ch. 9	W4 · Two Cliffs and an Ash Band: Build One Column of Time Diagrams and models	practice	MS-ESS1-4 is a California Grade 8 performance expectation. Here students do the hands-on half of it: use superposition, lateral continuity and two dated volcanic layers to combine strata from two sites into one ordered, partly dated record and decide where a boundary belongs. The sites and ages are invented, so no period names are needed, which respects the assessment boundary.
Ch. 9	W5 · Fossils Across a Line, and 4.54 Billion Years on a Meter Stick Data and graphing	practice	MS-ESS1-4 is a California Grade 8 performance expectation. Part A has students find the kind of fossil change that defines a boundary; Part B has them compute the true proportions of the eons, which is the quantitative reasoning behind 'how the geologic time scale is used to organize Earth's 4.6-billion-year history.' Eon names are given in a reference table, not recalled.
Ch. 9	W6 · Which Plan Divides the Cliff the Way Geologists Divide Time? Claim, evidence, reasoning	assesses	MS-ESS1-4 is a California Grade 8 performance expectation; this task produces evidence toward it from Grade 7 students. The CER asks for exactly what the PE states: a scientific explanation, based on evidence from rock strata, for how a geologic time scale is organized. The cliff and its numbers are invented, so the response relies on reasoning about strata, not on recalling the names of periods, which the assessment boundary excludes.
Ch. 9	W7 · Fix Dario's Exhibit: Finding the Errors in a Timeline of Earth Error analysis	practice	MS-ESS1-4 is a California Grade 8 performance expectation. Repairing claims about how the time scale is organized, how Earth's age is known and what the chart's proportions mean builds the accurate explanation the PE asks for; no period names are required to fix any error.
Ch. 9	W8 · Evidence Jigsaw: Twelve Clues to Earth's Past Collaborative investigation	practice	MS-ESS1-4 is a California Grade 8 performance expectation. Sorting real evidence into relative-order clues, absolute-age clues and event clues, then arranging it across Earth's 4.54-billion-year history, is the evidence-handling practice behind the PE's explanation; the time bins are given, so no period names are recalled.
Ch. 9	W9 · Design a Hallway Timeline That Tells the Truth About Time Transfer and design	practice	MS-ESS1-4 is a California Grade 8 performance expectation. Building a true-scale model of 4.54 billion years and discovering that all of human history fits inside a pencil line is the proportional reasoning behind explaining how the time scale organizes Earth's history. The event table gives names and dates, so the assessment boundary on recalling period names is respected.
Ch. 9	W10 · Deep Time Check: Retrieval Practice and Synthesis Retrieval and mastery check	assesses	MS-ESS1-4 is a California Grade 8 performance expectation; this quiz gathers evidence toward it from Grade 7 students. Items ask how the time scale is organized, how ages are attached and how strata are joined; no item requires recalling the name of a period or epoch or the events within it, in keeping with the assessment boundary.

Labs (6)

Chapter	Lab	Role	How it connects
Ch. 8	Lab 1 · Core the Hidden Layers: Reconstruct Strata You Cannot See Physical model	practice	Students use the relative-dating rules on physical evidence they gather themselves and explain the order of layers and events in another group's model. This builds the strata-reading half of the PE; it does not yet organize events on the geologic time scale.
Ch. 8	Lab 2 · The Quarry Case File: Order the Events and Bracket the Ages Evidence-based mystery	assesses	A Grade 8 PE in California's integrated sequence. The written sequence with a rule and evidence card for each step, plus the age brackets, is direct evidence that students can construct an explanation from rock-strata evidence. No period or epoch names are used, so the assessment boundary is respected; the time-scale half of the PE belongs to Lesson 9.
Ch. 8	Lab 3 · Where the Sediment Goes: Make a Layer, Then Cut a Canyon Classroom field investigation	supports	A Grade 8 PE in California's sequence. Seeing a second deposit land on top of the first, and seeing a channel expose matching layers on both of its walls, gives students a physical reason to trust the rules they then use to read strata.
Ch. 9	Lab 1 · Four and a Half Meters of Time: a String Model of Earth's History Physical model	practice	A California Grade 8 performance expectation met here as practice: students organize major events on a scaled model and reason about proportion, which prepares them to explain how the time scale organizes Earth's history. Event cards are chosen for their place in the story, not as names to memorize.
Ch. 9	Lab 2 · Three Sites, One History: When Did the Sea Creatures Vanish? Evidence-based mystery	assesses	A California Grade 8 performance expectation, placed here because the Grade 7 textbook teaches it. The written explanation in step 9 asks students to use evidence from rock strata (order, shared key beds, fossil disappearances, dated layers) to explain how the sequence organizes the region's history, which is the PE as written. In line with its assessment boundary, students never need to name periods or epochs.
Ch. 9	Lab 3 · The Boundary Committee: Deciding Where Deep Time Gets Divided Data-driven decision	practice	A California Grade 8 performance expectation. Students build toward it by deciding, from evidence in a layered sequence, where a time scale's divisions should fall and defending the decision, which is the reasoning behind how the scale organizes Earth's history.