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ScienceGrade 3

How Does Rock Turn Into Soil? Soil Formation for Kids

Weathering breaks big rocks into smaller and smaller pieces (physical, chemical, biological).

Learning Objective

Students will explain how rocks physically and chemically break down over time, and how decomposing plants and animals add organic matter, together forming soil (TEKS 3.10B).

What You'll Learn

  • Decomposing living things add dark, crumbly organic matter called humus to broken rock.
  • Soil = broken rock pieces + humus, mixed together ā€” and it takes a very long time to form.

Words to Know

Weathering
Rock slowly breaking into smaller and smaller pieces from wind, water, ice, or living things.
Ice freezing inside a crack can split a rock apart.
Humus
The dark, crumbly stuff left over when dead plants and animals rot and mix into the dirt.
The dark crumbly bits at the bottom of a leaf pile are humus.

Check What You Learned

Quick Quiz

1 / 5

What is it called when rock slowly breaks into smaller pieces?

Lesson Info

Grade 3
2026-10-19

Standards Alignment

  • TEKS 3.10B

    explore the physical properties of soil, including color and texture, capacity to retain

  • 4-ESS1-1

    make observations to provide

Keywords

3rd grade sciencescience for kidsrockturnintosoilformationkidsweatheringhumusTEKS 3.10B4-ESS1-1
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