S CIENCE S TUDY G UIDE Chapter Six

The rocky outer layer of the Earth’s surface is called the crust. Rocks break down during a destructive process called weathering Sediment forms when agents of mechanical weathering break rocks into smaller pieces.

Wind, water, and moving ice move sediments during the process called erosion. Small island can form during the constructive process called disposition. Contour lines connect points on a map that have the same elevation.

A topographic map shows the shape of surface features and their elevations. Most often salt water is found along the shorelines and near beaches relative to dry land. A plateau is a flat landform found at high elevation.

Underground caves, steep cliffs, and sand dunes often form near coastlines. Earth’s crust consists mostly of solid rock. There are several causes of mechanical weathering: ice, wind, moving water, and plant and animal activity.

C ONTINENTAL M ARGIN D IAGRAM

Chemical weathering can take place below the Earth’s surface when water seeps into deep cracks and dissolves minerals in rock. Acid rain seeps into cracks in the rock and dissolves below the surface.

Contour lines indicate elevation above sea level. Lines that are close together indicate a steep slope. Lines that are far apart indicate a gradual or gentle slope. Circular lines indicate peaks. A.Is a peak. 1.Gentle sloping side.

Wind, running water, and glaciers lead to erosion. Fast-flowing water and high- speed winds can carry small sediments quickly. Glaciers move most slowly, but are capable of carrying large amounts of sediment with them.

If a beaver built dams in small streams that run into a river a decrease in the water flow will cause the river to slow down. Sediments will be deposited along the bottom of the river. Flat land along the streams may flood because the stream flow is blocked. Flat lands along the river may experience less flooding due to decreased water flow and may become less fertile.

What type of map could you use to plan a location for building a house and dairy barn in an area that has hills and open fields? A topographic map indicates land features and elevation above sea level. Topographic maps identify sites that could be used for the house and barn and identify fields for the dairy to graze.

Waves of salty ocean water pound against and dissolve rock to form jagged cliffs and caves. Wind and water smooth exposed surfaces.

After heavy rains, the fields on each side of a river are flooded. After the flooding, farmers notice that not only is the soil in fields moist, but the soil has a new color and texture. The process that caused the changes: The river water carried sediments. During the flood, the river water covered the fields. The water eventually settled down through the soil, leaving a layer of sediment covering the soil in the fields.