Fossil Formation

Overview

In this lesson, students learn how fossils form and why they matter for understanding Earth’s history in New Zealand and beyond. They explore different fossil types and practise explaining the process using clear scientific language.

Learning intentions

• WALT explain how fossils form through processes such as burial, preservation, and mineral replacement.
• WALT identify and describe at least two types of fossils (for example, body fossils, trace fossils, moulds, casts).
• WALT describe why fossils are significant evidence for past environments and life.

Success criteria

• I can describe at least two types of fossils and how each type forms.
• I can explain, in sequence, a simple fossil-formation process (burial → conditions → preservation).
• I can give one reason fossils are important evidence about the past.

Curriculum links

• Developing understanding of how living things and environments change over time.
• Using scientific evidence to explain ideas about Earth’s history.
• Communicating findings using appropriate language for science (observations, explanations).
• Building skills for inquiry by asking questions, using models, and discussing evidence.

Lesson structure (30 minutes)

1. 0–3 min | Hook and purpose Show 2–3 images of different fossils (body fossil and trace fossil) and ask: “How could something soft become part of the rock?” Briefly connect to the unit focus: New Zealand landforms and Earth history.

2. 3–10 min | Mini-lesson: fossil formation Teach a simple model of fossil formation: an organism (or its activity) is quickly buried in sediment; over time, sediment layers build up; conditions help preserve hard parts or leave impressions; minerals can fill spaces or replace material. Emphasise safety and that fossils form over long time periods.

3. 10–16 min | Fossil types sorting (pairs) Give each pair a set of short description cards (e.g., “trace fossils show movement or feeding”; “body fossils are parts of organisms”; “moulds are impressions”; “casts are filled impressions”). Students sort into “type” groups and match each type to a brief “how it forms” statement.

4. 16–22 min | Whole-class discussion: explain with sentence frames Use sentence frames on the board:

• “A fossil is important because…”
• “This fossil type forms when…”
• “I can compare body fossils and trace fossils because…” Cold-call or ask for volunteer responses. Target students to use at least two fossil types in their explanation.

5. 22–27 min | Check for understanding (quick task) Students complete a short written response or diagram explanation:

• Describe two fossil types (label + one sentence each).
• Draw a simple “before → after” sequence for fossil formation (3 steps). Provide a dyslexia-friendly option: students can choose a narrated explanation to record (teacher audio or device) OR use fewer words with key labels.

6. 27–30 min | Exit ticket and wrap Exit ticket prompt: “In one paragraph, explain how fossils form and why they matter.” Students submit, or show verbally to a partner if preferred.

Resources

• Image set of fossil examples (body fossils, trace fossils, moulds/casts).
• Short reading cards describing fossil types (with visuals).
• Sentence frame strips for scaffolding explanations.
• Fossil formation diagram template (3-step sequencing).
• Writing materials: lined paper and/or label cards.
• Dyslexia-friendly reading texts (larger font, reduced text, high-contrast).
• Audio recording option (phones/tablets) or teacher-led recording.
• Timer and class discussion prompts.

Assessment

• Formative: teacher observes pair sorting accuracy and listening during discussion.
• Formative: quick task/exit ticket checks that students describe at least two fossil types and explain the basic formation sequence.
• Teacher notes: identify common misunderstandings (for example, “everything turns to fossil instantly” or mixing moulds/casts).

Differentiation

• Support (all abilities who need it): provide simplified readings with visuals; offer sentence frames and word banks (buried, sediment, minerals, impression, trace).
• Support for dyslexia: dyslexia-friendly reading option with reduced text; allow audio recording instead of extended writing; provide larger-format diagrams and label cards.
• Targeted teaching: during the sorting task, circulate with a small group to model how to match “type” to “how it forms”.
• Extension (advanced learners): students add one extra fossil type description and explain what evidence supports their claim (link to what the fossil shows about past environments).
• EAL learners: pre-teach key terms using gestures and quick examples; allow oral responses first, then shorten written tasks.

Extension (optional)

Research the oldest known fossils in New Zealand. Students present findings as a short poster or spoken summary including: what fossil it is, where it was found, approximate age, and why it matters.