--- title: "Rocks and soil" description: "Recognise that soils are made from rocks and organic matter, and that different soils have different properties" canonical: https://lightmysky.com/learn/science/rocks-and-soil-mt_yhhprm7dZK source: https://lightmysky.com/learn/science/rocks-and-soil-mt_yhhprm7dZK.md retrieved: 2026-10-19 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Rocks and soil Recognise that soils are made from rocks and organic matter, and that different soils have different properties Subject: Science · Area: Earth's Systems · Ages 7 to 8 Page: https://lightmysky.com/learn/science/rocks-and-soil-mt_yhhprm7dZK ## Ready when they can - State that soil is a mixture of broken-down rock particles and decomposed organic matter (humus) - Compare at least two types of soil (sandy, clay, loam) and describe their different properties - Explain that soil formation takes a very long time as rocks gradually break down ## Lesson: What is soil made of? You have compared rocks by their properties. Soil contains mineral particles from broken-down rock. It also contains organic matter from once-living things, plus air, water and living organisms. Humus is well-decayed organic matter. Soil is a mixture, not just crushed rock. Weathering breaks down rock. Water can enter cracks and freeze, widening them. Growing roots can widen cracks too. Small rock particles can mix with decaying material as soil develops. This takes a long time. A thin soil layer can take hundreds of years or longer to develop. *(drawing: Made-up test: equal soil samples receive equal water. After 5 minutes, collected water is sandy 9 mL, clay 2 mL and loam 5 mL.)* A taller test bar means more water drained through in the same time. Sandy soil usually drains quickly: its larger particles leave larger spaces. Clay has smaller particles and small spaces that hold water, so it usually drains more slowly. Sandy soil feels gritty. Wet clay can feel smooth and sticky. Loam mixes sand, silt and clay particles. Silt is smaller than sand but larger than clay. Loam often suits garden plants because it holds some water while letting extra water drain. It can contain humus too. **Recap.** Soil contains mineral particles, organic matter, air, water and life. It develops slowly. Soil types differ in particle sizes and drainage. ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Properties of rocks](https://lightmysky.com/learn/science/properties-of-rocks-mt_R6YoRXkRxS) ## Opens up - [The Rock Cycle](https://lightmysky.com/learn/science/the-rock-cycle-mt_NckKLZ3uCE) - [Weathering, Erosion and How Soil Forms](https://lightmysky.com/learn/science/weathering-erosion-and-how-soil-forms-mt_nQOPOt1VTH)