Weathering, Erosion, and Deposition
Aligned to MS-ESS2-2 — Next Generation Science Standards.
What this lesson teaches
Earth's surface is reshaped by three linked processes: weathering breaks rock into pieces, erosion carries those pieces away by water, wind, or ice, and deposition drops them somewhere new. Tiny changes each year add up over huge spans of time to carve canyons and build beaches.
Worked examples
Example 1
A river bend shows all three at once: the fast-moving outer bank is eroded and undercut, the sediment travels downstream, and on the slow inner bank it is deposited to form a sandbar. Over centuries this makes the river snake into wide S-shaped meanders.
Example 2
A glacier erodes by scraping rock with the debris frozen into its base, which is why glacial valleys are U-shaped and river valleys are V-shaped.
Example 3
Deposition builds land. The Mississippi delta is thousands of years of sediment that used to be Montana.
Practice questions
- Pour water down a tray of sand at different slopes and observe where material is picked up and where it piles up.
- Explain the difference between weathering and erosion in your own words with an example of each.
- Find a spot near your home showing deposition (like sand or gravel) and describe what likely carried it there.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Meteorización, erosión y depósito
La superficie de la Tierra se remodela mediante tres procesos ligados: la meteorización rompe la roca en fragmentos, la erosión los transporta mediante agua, viento o hielo, y el depósito los deja en un lugar nuevo. Cambios diminutos cada año se acumulan durante enormes lapsos de tiempo para tallar cañones y formar playas.
Ejemplo 1: Una curva de río muestra los tres a la vez: la orilla exterior de agua rápida se erosiona y se socava, el sedimento viaja río abajo, y en la orilla interior lenta se deposita y forma un banco de arena. Durante siglos esto hace que el río serpentee en amplios meandros en forma de S.
Ejemplo 2: Un glaciar erosiona raspando la roca con los escombros congelados en su base, por eso los valles glaciares tienen forma de U y los de río forma de V.
Ejemplo 3: La deposición construye tierra. El delta del Misisipi son miles de años de sedimento que antes era Montana.
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