Explain & Elaborate Science Practices Through Fossils

By Karen F. Schmidt – Rolling Hills Middle School

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Driving Questions for Unit:

  • How do scientists do their work?
  • What skills, practices, and tools are important to them?
  • What can be learned from fossils?

Intended Audience

Middle School
8th Grade Integrated Science

Time Frame

4 days (mostly 55 min periods, about 3 hours 45 mins total)


NGSS Performance Expectations:
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.

NGSS Disciplinary Core Ideas:
The History of Planet Earth
The geologic time scale interpreted from rock strata provides a way to organize Earth’s history. Analyses of rock strata and the fossil record provide only relative dates, not an absolute scale.

Relevant Science & Engineering Practices:

  • Asking Questions & Defining Problems
  • Developing & Using Models (diagrams)
  • Constructing Explanations and Designing Solutions
  • Obtaining, Evaluating and Communicating Information

Relevant Crosscutting Concepts:

  • Patterns
  • Scale, Proportion & Quantity
  • Cause & Effect

Relevant Common Core Standards:
Reading, Writing and Speaking:

Integrate quantitative or technical information expressed in words in a text with a version of that information expressed visually (e.g., in a flowchart, diagram, model, graph, or table).

Cite specific textual evidence to support analysis of science and technical texts.

Engage effectively in a range of collaborative discussions (one-on-one, in groups, teacher-led) with diverse partners on grade level topics, texts, and issues, building on others’ ideas and expressing their own clearly.

Resources & Materials

Showing recent fossil discoveries in the news:

Showing rock strata, how fossils form, and the law of superposition:



Articles and textbooks
Explaining how scientists work, how fossils form, and how scientists date fossils:
Holt Physical Science (or other) textbook section on “Who are Scientists?”
“How can dinosaur bones still be on Earth after 65 million years?” from the book How Come?: Every Kid’s Science Questions Explained by Kathy Wollard
“Radiometric Dating”

Video Clips
TED Ed: How to Fossilize Yourself
PBS Learning Media: Grand Canyon: Evidence of Earth’s Past

Informative Websites

Trilobite or nautilus, new specimens that are older than Gatun
Fossil Guide or poster (e.g. A Guide to Common Fossils of the Gatun Formation )
Student science notebooks
OPVL Strategy (must be adapted for science visuals):

Guest speaker: (if possible) a local paleontologist

Guiding questions

  1. How do scientists do their work?
  2. How do fossils form?
  3. How do scientists know how old a fossil is?

Key Academic and/or Scientific Language

Paleontology, geochemistry, fossil, scientific diagram, fossilization, strata, sediment, decomposition, relative dating, radiometric dating, law of superposition, bracketing


What knowledge and skills will students acquire?
Students will be able to:
Use a science notebook for keeping written notes and diagrams

  • Construct an explanation to answer a scientific question
  • Analyze and interpret scientific diagrams
  • Read and summarize a scientific article
  • Obtain information from a variety of media sources
  • Evaluate the credibility of sources of information


  • Science notebooks will be assessed for completeness.
  • Students will take a Pop Quiz and a unit test requiring application of skills and knowledge to a new situation (open notebook).
  • Students will repeatedly be asked to reflect on which Science Practices they are using, and list examples, throughout the unit.


Teaching phase

What sequence of teaching and learning experiences will equip students to develop and demonstrate the desired learning goals? Include agenda and time estimates.

Day 1–Explain
Unit Driving Questions: How do scientists do their work? What skills, practices and tools are important to them? What can be learned from fossils?

  • Warm-Up: Review student questions about Gatun fossils, focus on “How do fossils form?” and on Science Practice #6: Constructing Explanations
  • Whole class discussion: Ask students what kind of scientist would want to know how fossils form (a geochemist) and who could explain it in a diagram (a science illustrator). Guide discussion: Where to get more info? (a textbook) How do scientists use textbooks? (as a reference source)
  • Activity: Students read to partners from Holt Physical Science textbook to learn about what a Geochemist does, as well as a Scientific Illustrator. Class discussion.
  • Video clip: TED Ed: How to Fossilize Yourself, then discuss using Pair-Share, and whole class discussion of steps required to become a fossil.
  • Mini-Lesson: How to read a science article, including effective highlighting, identifying key terms, and pulling out information for a bullet point summary.
  • Activity: Students read the article, “How can dinosaur bones still be on Earth after 65 million years?” Teacher first shows source of article (book) and models reading strategies for class by thinking aloud while reading the title, interpreting the accompanying cartoon, and reading the first paragraph. Students then read independently and make a bullet summary in their notebooks. Each student’s article with highlighting is added to his/her Science Notebook.

Day 2—Explain (cont’d)
Focus Question: How do fossils form? What is the process of fossilization?

  • Warm-Up: Photo of giant dinosaur bone in the news. How did it become a fossil?
  • Activity: Students continue summarizing science article, “How can dinosaur bones…” Class identifies and discusses key terms identified in article, e.g. decompose
  • Whole class discussion: What was learned about fossilization from article?
  • Mini-Lesson: Interpreting Scientific Visuals using OPVL Strategy (See Resources & Materials). Teacher models OPVL strategy using a familiar visual: the cover of the Gatun Fossil Guide.
  • Activity: Students practice OPVL strategy by interpreting visual from Pearson on Fossil Formation, discuss with partners, and fill out OPVL chart kept in notebook
  • Whole Class discussion: Which Science Practices did you use today? (Asking Questions, Using Models, Constructing Explanations, Obtaining Information)
  • Notebook stamp

Day 3—Explain (Cont’d)
Focus Question: How do scientists know how old a fossil is?

  • Warm-Up: Introduce focus question and brainstorm what students already think they know about how to tell the age of a fossil
  • Activity: Students interpret visual called “Bracketing a Fossil” showing rock strata, fill out OPVL chart
  • Whole class discussion: source check UCMP website, discuss relative vs. numerical dating, discuss law of superposition
  • Activity: Students read and highlight text on Radiometric Dating, class discusses new terms, e.g. radiometric
  • Whole Class discussion: Which Science Practices did you use today? (Asking Questions, Using Models, Constructing Explanations, Obtaining Information)
  • Notebook stamp

Day 4—Explain & Elaborate
Focus Questions: How do scientists know how old a fossil is?

  • Warm-Up: Show real trilobite fossils from teacher collection, have students ask questions about them
  • Video clip: PBSLM: Grand Canyon: Evidence of Earth’s Past
  • Whole class discussion: What makes the Grand Canyon so special to scientists? How is it the similar to/different from other spots on Earth?
  • Activity: Students interpret visual on Geologic Time and fill out OPVL chart with partner, add to notebook
  • Pop Quiz: Use the Geologic Time diagram to answer the following questions:
    1. What is the estimated age of the Earth?
    2. When did trilobites live?
    3. How many major extinctions happened in Earth’s history, and when?
    4. If the Gatun fossils are 10 million years old, during which era did they live?
  • Score quizzes and show how answers were found in diagram
  • Wrap-Up Pair-Share: Which would you prefer—reading a book about Earth’s history or looking carefully at a Geologic Time diagram? Why?

 Reading | Writing | Speaking | Listening Strategies

  • Reading to obtain information from books, diagrams, videos and articles
  • Writing questions and answers in Science Notebook
  • Speaking practice while developing explanations with partners
  • Listening for information in video clips
  • Listening to a guest speaker (if available)

Learning Progression

Prior Knowledge needed for this lesson (or to be revisited):

  • How to use a science notebook
  • Generally what are the 8 Science & Engineering Practices (already listed in notebook)
  • How to ask scientific questions

Current Knowledge/Skill
Same as objectives listed above

  • How to read and obtain information from a science article
  • How to closely read and interpret scientific diagrams using the OPVL strategy
  • How to construct explanations to answer scientific questions
  • How to evaluate credibility of information sources

Future Skill Connections

  • How to create a detailed scientific diagram for a poster
  • How to write an expository essay to explain a scientific concept
  • How to use models to explain scientific theories
  • How to interpret computer animations and use apps for explaining science concepts


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