Rock Layers & Relative Dating

CONCEPTUAL

Science›Dinosaurs & Paleontology|Ages 9—11|ID: mt_EGIlsfHxb6

Understand that rock layers (strata) form in sequence with the oldest at the bottom and the youngest at the top, and that fossils found in deeper layers are older — this is the principle of relative dating

Mastery Evidence

Explain that sedimentary rock forms in layers with the oldest at the bottom
Use a diagram of rock strata to determine which fossil is older based on its position
Define relative dating as working out the age of something by comparing its position in rock layers

Assessment Prompt

“If [child] saw a cliff with layers of rock, could they explain that the bottom layers are the oldest and that fossils found deeper down lived longer ago?”

Prerequisites4

How Fossils Form
hardAges 7—9
Types of Rock
softAges 7—9
Properties of materials
softAges 7—8
The Mesozoic Era
softAges 7—9

Show full prerequisite tree

How Fossils Form hard
Must understand fossil formation in sediment before understanding rock layer sequencing
- Fossils & Palaeontologists hard
  Must understand what fossils are before learning how they form in detail
  - Dinosaurs Were Real hard
    Must understand dinosaurs are extinct before learning fossils are how we know about them
- Real Dinosaurs vs Fiction soft
  Understanding how fossils form (and that fossil evidence is the basis of dinosaur science) is enriched by the prior understanding that dinosaurs are real animals distinct from fictional or commonly-confused creatures — scientific reasoning starts from accurate categorisation
  - Famous Dinosaur Species hard
    Must know some dinosaurs before distinguishing them from non-dinosaurs
    - Dinosaurs Were Real hard
      Must understand dinosaurs existed before learning to name species
- How fossils form soft
  Curriculum fossil formation topic (GB Y3) directly underpins detailed dinosaur fossil formation understanding
  - Properties of materials hard
    Must examine rocks before understanding how fossils form within rock
    - Grouping Materials soft
      Grouping materials by properties supports grouping rocks by properties
      - Describing Material Properties hard
        Must describe properties before using them to group materials
        
        States of Matter Vocabulary soft
        Describing physical properties of materials uses solid/liquid/gas vocabulary introduced in the states of matter LANGUAGE node
        
        Naming Everyday Materials hard
        Must name materials before describing their properties
        
        Objects vs Materials hard
        Must distinguish objects from materials before naming specific materials
  - Living, Dead & Never Alive soft
    Understanding living vs dead supports understanding what gets fossilised
    - Common Plants & Trees soft
      Knowing plant names helps distinguish living from non-living
    - Living Things Vocabulary hard
      Comparing living, dead, and never-been-alive things requires the life processes vocabulary to give reasons
    - Naming Common Animals soft
      Knowing animal groups helps distinguish living from non-living
Types of Rock soft
Dinosaurs rock strata/relative dating benefits from knowing rock types (igneous, sedimentary, metamorphic)
- Earth's Layers soft
  Rock types benefit from knowing Earth has hot interior (explains melting for igneous)
  - What Is a Volcano hard
    Understanding layers requires knowing what a volcano is (motivation for internal structure)
  - Earth Is Made of Rock hard
    Earth's layers builds on knowing Earth is made of rock
- Properties of materials soft
  Volcanic rock types topic parallels curriculum rocks classification
  - Grouping Materials soft
    Grouping materials by properties supports grouping rocks by properties
    - Describing Material Properties hard
      Must describe properties before using them to group materials
      - States of Matter Vocabulary soft
        Describing physical properties of materials uses solid/liquid/gas vocabulary introduced in the states of matter LANGUAGE node
      - Naming Everyday Materials hard
        Must name materials before describing their properties
        
        Objects vs Materials hard
        Must distinguish objects from materials before naming specific materials
- What Is a Volcano hard
  Igneous rock concept links to lava cooling from volcanoes
- Earth Is Made of Rock hard
  Rock types build on knowing Earth is made of rock
Properties of materials soft
Understanding rock classification (sedimentary/igneous/metamorphic) helps understand strata and relative dating
- Grouping Materials soft
  Grouping materials by properties supports grouping rocks by properties
  - Describing Material Properties hard
    Must describe properties before using them to group materials
    - States of Matter Vocabulary soft
      Describing physical properties of materials uses solid/liquid/gas vocabulary introduced in the states of matter LANGUAGE node
    - Naming Everyday Materials hard
      Must name materials before describing their properties
      - Objects vs Materials hard
        Must distinguish objects from materials before naming specific materials
The Mesozoic Era soft
Understanding geological periods helps contextualise the strata timeline
- Famous Dinosaur Species soft
  Knowing species names helps when assigning them to time periods
  - Dinosaurs Were Real hard
    Must understand dinosaurs existed before learning to name species
- Dinosaurs Were Real hard
  Must understand dinosaurs existed long ago before placing them in geological periods
- Dinosaur Sizes soft
  Placing the Mesozoic periods in order and understanding that different dinosaurs lived in different periods is contextualised by the prior knowledge that dinosaurs varied enormously in size — size variation across time periods supports the concept of evolutionary change
  - Famous Dinosaur Species hard
    Must know some dinosaur species before comparing their sizes
    - Dinosaurs Were Real hard
      Must understand dinosaurs existed before learning to name species

Unlocks1

Radiometric Dating
hardAges 11—13