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Fossils & Geologic Time

Sixth graders discover how fossils and rock layers reveal Earth’s deep history — using the law of superposition and index fossils to read the story of life and time recorded in the rocks beneath our feet.

Grade 6Earth History50 minutes1 class period5E ModelExplicit teaching4 StandardsNGSS
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Lesson at a Glance

Everything you need before the bell rings

Learning Objectives

Students will be able to…

  • ✓Explain what a fossil is.
  • ✓Explain the law of superposition.
  • ✓Use relative dating.
  • ✓Explain index fossils.
Essential Question

Rock layers are like the pages of an ancient book, and fossils are its illustrations. How do scientists read this rocky record to figure out what happened long before humans existed?

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Lesson Phases
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Vocabulary Terms
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Standards Aligned
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Interactive Task
Match It · Interactive

Match the Earth-History Term

Project this and match each term to its description — tap a term, then tap what it means.

🦴 Match each Earth-history term to its descriptionTry it
Term
Description
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The Lesson · 5E Instructional Model (Engage · Explore · Explain · Elaborate · Evaluate)

50 minutes, five moves

Tap any phase to open the teacher moves and student actions.

1

Engage — Pages of Rock

5 min

Rock layers are like pages of a book — how do we read Earth’s history in them?

👩‍🏫 Teacher Moves

  • Show layered rock with fossils.
  • Ask how to read it.
  • Pose the question.

🎒 Student Actions

  • See the layers.
  • Wonder how.
  • Predict the idea.
2

Explore — Explore the Record

12 min

Students investigate.

👩‍🏫 Teacher Moves

  • Send students to Match the Earth-History Term.
  • Note superposition.
  • Note index fossils.

🎒 Student Actions

  • Match them.
  • Note superposition.
  • Note index fossils.
3

Explain — Reading the Layers

13 min

Students explain.

👩‍🏫 Teacher Moves

  • Explain fossils.
  • Explain the law of superposition.
  • Explain relative dating.

🎒 Student Actions

  • Explain fossils.
  • Explain superposition.
  • Explain dating.
4

Elaborate — The Story of Life

13 min

Students elaborate.

👩‍🏫 Teacher Moves

  • Order rock layers by age.
  • Use index fossils to date.
  • Explain what fossils reveal.

🎒 Student Actions

  • Order layers.
  • Use index fossils.
  • Explain it.
5

Evaluate — Evaluate

5 min

Students conclude.

👩‍🏫 Teacher Moves

  • Explain the law of superposition.
  • Use relative dating.
  • Hand out the exit ticket.

🎒 Student Actions

  • Explain it.
  • Date layers.
  • Complete the exit ticket.
Standards Alignment

Built to the standards you report on

Aligned to the Next Generation Science Standards (Middle School Earth & Space Science).

NGSS
MS-ESS1-4

Construct an explanation using rock strata to organize Earth’s 4.6-billion-year history.

NGSS
MS-LS4-1

Analyze the fossil record for evidence of change over time.

NGSS
MS-ESS2-3

Interpret patterns in rock and fossil data.

NGSS
SEP-7

Engaging in argument from evidence.

Differentiation

One lesson, every learner

Multilingual Learners

ELL / EMERGING READERS
  • Rock-layer diagram.
  • Sentence frame: “Older rocks are on the ___.”
  • Use layered models.

Support & Access

IEP / 504
  • Start with “older on the bottom.”
  • Match one pair at a time.
  • Use a layer diagram.

Stretch & Extend

GIFTED / EARLY FINISHERS
  • Order complex rock layers.
  • Build a geologic time scale.
  • Use index fossils to correlate sites.
Materials

What to gather

  • 📽️Projector / board
  • 🦴Fossil samples
  • 💻Match the Earth-History Term
  • 📄Rock-layer diagrams
  • ✏️Pencils
  • 🎫Exit-ticket slips
Vocabulary

Key terms — hover for a quick definition

fossilpreserved remains of an ancient organismsedimentary rockrock formed in layersrelative datingordering rocks by agelaw of superpositionolder layers lie below younger onesindex fossila fossil used to date layersstratarock layersgeologic timethe vast history of Earthfossil recordthe total collection of fossils
Evaluate

Exit Ticket

Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.

QUESTION 1
What is the law of superposition?
In undisturbed rock layers, the oldest layers are on the bottom and the youngest on top.
QUESTION 2
What is an index fossil used for?
To date and compare rock layers — it’s a widespread fossil from a short time span.
QUESTION 3
Where are most fossils found?
In sedimentary rock (which forms in layers).

Elaborate: build a time scale.

Have students order a set of rock layers using the law of superposition and index fossils to reconstruct the sequence of events. A printable fossils-and-time sheet is in the Science library.

Study · Flashcards

Study the key terms

Tap a card to flip it, then rate whether you knew it. Built from this lesson’s vocabulary.

🃏 Fossils & Geologic TimeFlip
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Practice · Quiz

Check your understanding

A quick self-check with instant feedback, drawn from this lesson’s key terms.

📝 Fossils & Geologic TimeQuiz
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Question 1
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Practice · Worksheet

Printable worksheet

A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.

🖨️ Fossils & Geologic TimePrint
Name: ________________________
Date: ____________

Part A · Write the word that matches each meaning

Word bank: fossil, fossil record, geologic time, index fossil, law of superposition, relative dating, sedimentary rock, strata
  1. ordering rocks by age
  2. the vast history of Earth
  3. preserved remains of an ancient organism
  4. a fossil used to date layers
  5. the total collection of fossils
  6. rock layers
  7. older layers lie below younger ones
  8. rock formed in layers

Part B · Show what you learned

  1. What is the law of superposition?
  2. What is an index fossil used for?
  3. Where are most fossils found?
Answer key — Part A: 1) relative dating · 2) geologic time · 3) fossil · 4) index fossil · 5) fossil record · 6) strata · 7) law of superposition · 8) sedimentary rock
Part B: 1) In undisturbed rock layers, the oldest layers are on the bottom and the youngest on top. 2) To date and compare rock layers — it’s a widespread fossil from a short time span. 3) In sedimentary rock (which forms in layers).