Landforms Investigation 3 – Go With The Flow. Part 1: Slope Vocabulary – Slope - the angle or slant of a stream channel or land surface Main Ideas – Canyons.

Landforms

Investigation 3 – Go With The Flow

Part 1: Slope

• Vocabulary– Slope - the angle or slant of a stream channel or

land surface• Main Ideas– Canyons are deeper and deltas are longer in a

stream table model with a steep slope.– Water flowing through channels with steep slopes

causes more erosion.

Part 2: Flood

• Vocabulary– Flood – a very heavy flow of water, which is greater

than the normal flow of water and goes over the stream’s normal channel.

– Flash Flood – rises and falls rapidly with little or no advanced warning. Can be caused by heavy rainfall, dam failure, or the thaw of an ice jam.

• Main Ideas– Floods erode an unusual amount of material.– Floods erode materials more quickly than normal

water flow.

Science StoriesRivers and Controlling the Flow

River Features• Many factors influence the shape of the land

around river channels:– Earth materials underneath– Force of the water– Amount of sand and rock carried along by the river

Science StoriesRivers and Controlling the Flow

• As a river continues downstream, it often flows over wide areas of sediment called flood plains– Sediment is deposited by the river when it

overflows its banks and floods nearby land• A large river may speed up as it nears its

mouth, however it actually slows when it reaches the mouth.

Science StoriesRivers and Controlling the Flow

Mississippi River• Begins at a small lake in Minnesota.• Divided into 2 regions – 1) fast, clear flowing section and 2) a

more sluggish, sediment-filled section.• Drains the central portion of the country (40% of the US).• Important for commerce and transportation.Hudson River• Begins in Adirondack Mountains and extends to NY Harbor.• Discovered by Henry Hudson in 1609 (thought it connected the

Atlantic and Pacific oceans).• Important drainage basin in the Northeast.• Important for commerce and transportation.

Science StoriesRivers and Controlling the Flow

History of Flow Control• A levee is an embankment or mound along a

river’s edge. Miles of levees line the Mississippi River.– Natural levees formed when rivers deposit large

quantities of sediment after a flood– Artificial levees are higher and wider

• Erie Canal was built to connect the Hudson River to the Great Lakes.

Part 3

• Vocabulary– Levee – an embankment along a stream that protects land

from flooding. Levees can be natural or constructed.– Dam – a construction or wall across a river that holds back

water flowing through the river, creating a reservoir or lake.

– Floodplain – area around a river that is covered by water flowing over the riverbank during a flood.

• Main Ideas– People control the flow of water in a river with dams,

levees, and new channels.

Science StoriesShapes of the Earth

• Landforms result from a combination of constructive and destructive forces:– Constructive include crust deformations (i.e.,

mountains), volcanic eruptions (i.e., islands), and deposition of sediment (i.e., deltas, islands)

– Destructive include weathering and erosion (i.e., canyons, caverns)

• The Earth’s surface is constantly in motion– Crust is broken into 30 tectonic plates

• Beneath the crust is the mantle, which is made out of molten rock, or magma.– The crust floats on the molten rock

• When plates collide, they push upward against each other, creating mountains (uplift).– Mountains also form when magma pushes up a

portion of the crust.

Science StoriesShapes of the Earth

• Earthquakes happen when two plates move past each other along a fault, or break in the Earth’s surface.

• Volcanoes form where plates collide and where they pull apart (rift). They also form over hot spots in the middle of plates.

• Waves can deposit sand and soil and create beaches and sand dunes. They can also erode the shoreline.

Science StoriesShapes of the Earth

• Glaciers are large, moving pieces of ice. They are unpredictable and ever-changing, and change the shape of the land.– They move slow, but pick up boulders, sand, and other

sediment as they move, and deposit them in a new place.• Caverns are formed from either:

– 1) acid rain dissolving limestone– 2) action of waves against sea cliffs– 3) sand carried by strong wind– 4) cooling lava

• Sinkholes are caused by caverns forming too close to the surface and the ceiling collapsing.

Science StoriesShapes of the Earth