Weathering & Erosion Types
What is the process that breaks rocks into smaller pieces without changing their chemical composition
Mechanical/physical weathering
Which agent of erosion is caused by moving water in rivers and streams?
Running water
Where do rivers typically deposit their heaviest sediments when the water slows down quickly?
At the riverbed near the source or inside bends — often forming alluvial fans or bars
What is a simple classroom model that shows how erosion by water moves sediment downhill?
Pouring water over a tray of soil/sand
What is the term for the top layer of soil that contains mostly decomposed plant material?
Topsoil or humus-rich layer
What type of weathering changes the chemical makeup of rock, such as when acid rain dissolves limestone?
Chemical weathering
What agent of erosion moves sand along a beach and shapes dunes?
Wind
Where does deposition commonly occur where a river meets a standing body of water, forming a fertile landform?
Delta
When making a model of weathering, what two factors should you include to show both physical and chemical weathering?
A mechanical force (e.g., freezing/thawing or abrasion) and a chemical agent (e.g., vinegar/acid
What do scientists call the vertical sections of soil that show distinct layers?
Soil horizons or soil profile
What kind of weathering involves organisms like plant roots breaking rock apart?
Biological weathering
Which slow-moving agent of erosion can grind rock and carry large amounts of debris across landscapes?
Glaciers/ice
What environment of deposition forms when wind drops sand and creates mounds?
Sand dunes/desert environments
Name one way to improve a physical model so students can see differences in erosion rates (one variable to change).
Change slope/angle of the tray, amount of water flow, or type of sediment
In a soil profile, which layer is likely to be mostly weathered rock fragments with little organic material?
The C horizon or parent material
Name the process that moves rock particles away and wears down surfaces (often confused with weathering).
Erosion
: What agent of erosion can both dissolve rock and carry dissolved minerals, affecting chemical weathering?
Water (including groundwater)
Where would fine silt and clay be deposited after being carried far from their source?
In deep lakes or the ocean (continental shelf), forming layers of fine sediment)
How can a model demonstrate human impacts that increase erosion? Give a short description.
Remove plant cover from part of the model and run water to show increased runoff and sediment loss in that area.
Name two materials you would expect to find in soil besides rock particles.
Organic matter (decomposed plants/animals), water, air, and living organisms
Explain the difference between weathering and erosion in one sentence.
Weathering breaks down rock in place; erosion transports the broken pieces away.
Describe how humans can act as an agent of erosion — give one clear example.
Deforestation or construction removes vegetation, exposing soil to runoff and increasing erosion.
Explain how a beach forms as an environment of deposition (two sentences).
Waves and longshore currents carry and sort sand along the shore. When energy decreases, sand is deposited, building the beach.
Design challenge (short): List three components your model must include to demonstrate weathering, erosion, and deposition working together.
A source of rock/soil to weather, a moving agent (water/wind/ice) to transport material, and an area where the agent slows so material deposits.
Name the 5 layers of soil
Humus, Topsoil, Subsoil, Parent Material, Bedrock