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4th grade · Science · Unit 8 of 11

Rocks, Layers & Erosion

Rock layers tell stories. Water, ice and wind reshape land.

What your child practices

Practices reading rock layers and fossils as clues to how a landscape changed, and how weathering and erosion by water, ice, wind and plants shape the land, with New York's Finger Lakes, Niagara Falls and Letchworth gorge as examples.

New York State Learning Standards learning standard: 4-ESS1-1; 4-ESS2-1 · rock layers and fossils show landscape change, and weathering and erosion shape the land

How we explain it

Children can open this short lesson before they practice.

  1. Rock layers tell stories. The oldest layer is usually at the bottom.
  2. Water, ice and wind wear rock away and carry it off.
  3. Rivers tumble rocks until they are smooth, and can carve deep gorges over time.
  4. Plants and their roots slow erosion.

Example: Why are rocks in a river smooth and round? Running water rolls the rocks against each other. Their sharp edges wear away. Answer: water tumbled them

Rocks, Layers & Erosion in New York

In the New York State Learning Standards, this is unit 8 of 11 in 4th grade Science, after Waves & Codes and before Maps & Natural Hazards.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: New York State Education Department (NYSED)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    In rock layers, the oldest layer is usually at the…

    • bottom
    • middle always
    • side
    • top

  2. Question 2

    The Finger Lakes formed when huge glaciers…

    • fell from space
    • erupted lava
    • carved deep valleys that filled with water
    • were dug by people

  3. Question 3

    Big boulders sit in New York fields far from where they formed. They were moved by…

    • raindrops
    • birds
    • glaciers
    • volcanoes

  4. Question 4

    Plant roots growing in cracks can…

    • glue rock together
    • make rock
    • break rock apart
    • melt rock

  5. Question 5

    Rain falling on a slope with no plants will…

    • wash away more soil
    • make new rock
    • grow plants at once
    • wash away less soil

  6. Question 6

    Layers: sea fossils at the bottom, then river sand, then land plants on top. What changed?

    • Land became sea
    • Nothing changed
    • The layers were glued
    • A sea became land over time

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