Hank, Earth's Changing Surface Flashcards
Landforms
A part of the Earth’s surface that has a unique shape.
It was created by nature.
Most changes in the landscape of our Earth have occurred over
_________________________
Hundreds, thousands or millions of years.
Sediment
Small rocks, pebbles or sand.
Weathering
Breaks rocks and sediments into smaller pieces.
Abrasion
When rocks and sediment grind against each other and break down into smaller pieces.
Erosion
Gradual movement of sediment from one place to another.
Maybe moved by water, glacier or wind.
Deposition
Gradual build-up of eroded sediment.
Like a sandbar or a beach.
How can water, wind and ice cause erosion and deposition.
After sediment is eroded by moving water, wind or ice
Wind blows over beaches and sand dunes. Glaciers creep slowly down mountainsides.
Source of a river
Where a river begins.
Like a spring or melting mountain snow.
Riverbanks
The sides of a river.
Mouth of a river.
Where a river meets another body of water.
Like a lake, another river or the ocean.
Delta
A landform at the mouth of a river.
Made by moving water has deposited silt, sand, soil and rocks.
4 factors that shape a river.
- Slope of the land.
- Speed of the water.
- Hardness of the Earth’s surface.
- Amount of water.
Slope
How steep the land is that water is flowing down.
Glacier
A huge mass of moving ice.
Conditions that form a glacier.
- Lots of snow.
- Cold climate all year.
- Built over hundreds of thousands of years.
- When big enough, gravity makes it flow downhill.
How much do glaciers move?
1-2 inches per day
What causes a glacier to move?
Gravity and weight
The bottom of the ice melts and gets slippery.
How do glaciers weather rock and mountains?
Glaciers pick up rock as they move down mountains, they cause abrasion, polish the rock, and cut long scratches.
Glacial striations
Cuts and long scratches glaciers make in rocks.
Moraines
Glaciers can push big piles of rock and sediment into mounds and hills along their sides and in front of them.
Lakes often form behind moraines when glaciers melt.
Erratics
Large rocks or boulders carried along by glaciers and then left behind in strange places.
How are glacial valleys different from river valleys?
River valleys have a narrow V shape.
Glacial valleys have a wide U shape.
Why are people only partially right when they think landforms are shaped by the wind?
Landforms like Hoodoos were shaped by wind AND water.
How does cap rock protect a Hoodoo?
Cap rock is a shell of harder rock that protects the soft rock underneath.
Explain how sand is formed.
Mountain rock and dirt weathers, washes downhill into rivers, and breaks into smaller and smaller pieces. Wind blows the sand into other rocks and sand until it is shaped like a ball.
What 3 conditions are needed for sand dunes to form?
- Dry and loose sand.
- A strong, steady wind.
- An area large enough for sand to blow around.
3 types of physical weathering.
- Abrasion - rocks grinding together.
- Ice wedging - water freezes in the rocks and breaks them
- Exfoliation - large slabs of rock can break off and slide away
3 types of biological weather
- Plants - may grow in cracks in rocks and break them up.
- Animals - beetles, ants, marmots burrowing through cracks.
- Humans - roads, tunnels, dams and rivers
2 types of chemical change
- Dissolution - acid rain dissolving rock.
2. Oxidation - the iron in minerals reacts with oxygen in the air and rusts
The weathering of rock creates ____________ and _____________.
Sediment and Soil
Describe the 4 layers that make up the Earth
- Inner core - a SOLID of iron and nickel
- Outer core - a LIQUID layer of iron and nickel
- Mantle - the thickest layer of the earth, solid and semi-molten
- Crust - solid rock that is the surface of the earth, thin like a shell
The earth’s crust is made up of numerous pieces called
_____________________ ___________________ which float on the mantle.
Tectonic plates
3 types of plate boundaries
- Convergent boundaries - 2 plates collide
- Divergent boundaries - 2 plates move away from one another
- Transform boundaries - 2 plates slide past each other
How are folded mountains formed?
When two plates collide.
One goes down and another goes up making the folded mountain.
Explain why millions of years from now, the mountains around us may no longer exist.
Moving water from rainfall and snowmelt start breaking down the mountain. Ice and wind wear it down too.
Landscape
A large area of land or scenery.
Usually has many surface features like hills, valleys or rivers.
