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4th grade · Science · Unit 7 of 7

Rock Layers & Erosion

Weathering, erosion and what rock layers tell us.

What your child practices

Practices how water, ice, wind and plants weather and erode rock, and how rock layers and fossils show how a landscape changed, with examples from Minnesota's river valleys and the North Shore.

Minnesota K-12 Academic Standards benchmark: 4E.1.2.1.1; 4E.3.2.1.1 · weathering and erosion, and what rock layers and fossils tell us about change

How we explain it

Children can open this short lesson before they practice.

  1. Weathering breaks rock. Erosion moves it away.
  2. Erosion is faster on bare ground than on ground covered in plants.
  3. In rock layers, the oldest layer is usually at the bottom.
  4. Fossils of sea animals show a place was once under water.

Example: Which hill erodes faster: a bare hill or a grassy hill? Grass roots hold the soil. A bare hill has nothing holding it. Answer: the bare hill

Rock Layers & Erosion in Minnesota

In the Minnesota K-12 Academic Standards, this is unit 7 of 7 in 4th grade Science, after Energy Resources.

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: Minnesota Department of Education (MDE)

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…

    • middle always
    • side
    • top
    • bottom

  2. Question 2

    Wind erosion is common in…

    • under glaciers
    • oceans
    • rainforests only
    • deserts

  3. Question 3

    Which slows erosion on a hillside?

    • Pouring water
    • Digging
    • Plants and their roots
    • Removing all plants

  4. Question 4

    Which can cause weathering?

    • A shadow
    • Moonlight
    • Water freezing in cracks
    • A rainbow

  5. Question 5

    Plant roots growing in cracks can…

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

  6. Question 6

    Over thousands of years, the Mississippi River carved a deep valley through layers of rock in southeastern Minnesota. This is an example of…

    • erosion by water
    • an earthquake
    • melting rock
    • a volcano

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