1. Earth’s Features

2. ¾ of Earth is covered by water.
Most of the water is in oceans.
Earth has 7 great areas of land called continents.
North America (where we live)

3. Landforms Mountain – tallest; has steep sides and pointed top
Valley – low land between hills or mountains.
Canyon – deep valley with steep sides
Plain – land that is wide and flat
Plateau – steep sides and a flat top; higher than land around it.
Coast - land that borders the ocean
Peninsula – land surrounded by water on 3 sides
Island – land with water all around it

4. Water Features Ocean – large bodies of salt water
Lake – water that is surrounded by land; can be fresh or salt water
River – large body of moving fresh water
Glacier – a large, slow moving, block of ice

5. Land Features in the Ocean
Ocean Floor – Land below the ocean.
Continental Shelf – a huge plateau that lies under the ocean at the edge of a continent.
Abyssal Plain – wide and flat, stretches thousands of kilometers across the ocean.
Trench – a canyon on the ocean floor.

6. Layers of the Earth Crust – The outermost layer
Made up of the continents and the ocean floor
The thinnest and coolest layer
Mantle – Layer below the crust
Part solid rock
Part nearly melted rock that is soft and flows (like putty)
Core – Deepest and hottest layer of Earth
Outer Core – Melted Rock
Inner Core – Solid Rock

8. Sudden Changes to Earth

9. Earthquakes
A sudden movement of the rocks that make up the Earth’s crust
The ground shakes or vibrates.
Some earthquakes are very weak and aren’t even noticed while others are very strong.
Some can crack roads or even cause mountains to fall!

11. Volcanoes A mountain that builds up around an opening in Earth’s crust
Melted rock (magma) moves through a large crack in the crust and flows onto land.
When it flows onto land it is called lava.
If the lava is forced out in an explosion a large part of the mountains is blown away
Materials from volcanoes can cause a lot of damage to buildings and living things.

14. Landslides The rapid movement of rocks and soil down a hill.
Caused by gravity.
Can change a hill or mountain very quickly.

16. Floods Water that flows over land that is usually dry.
Can be caused by heavy rains and melting snow.
Flood waters are very strong.

18. Weathering, Erosion, and Deposition

19. What is Weathering?
The breaking down of rocks into smaller pieces is called weathering.
Happens so slowly you cannot see it.
Can take millions of years.

20. What causes weathering?
Running water and Wind
Pick up small rocks that scrape against other rocks
The scraping slowly wears away rocks.
Rain and Melting Snow
Enter cracks in rocks
Water freezes and expands widening the crack before thawing and becoming liquid again
Over time, repeated freezing and thawing breaks rocks apart.

21. What causes weathering?
Living Things
Plants grow in the cracks of rocks
The roots eventually split rocks apart
Animals dig in the ground
They uncover buried rocks
The uncovered rocks can then begin to weather.

22. What is Erosion? The movement of weathered rock
Moving water, wind, and glaciers and gravity all cause erosion
Happens very slowly
Weathering and erosion work together to change the land

23. Moving Water and Wind Moving water and wind picks up rocks and sand
The rocks and sand may be carried far away and dropped in new places.
Deposition – the dropping off of weathered rock.

24. Glaciers
While moving a glacier picks up and carries rocks of all sizes.
The ice at the bottom of the glacier freezes onto rocks and tears them out of the ground
Can move rocks the size of a house.
As glacier melts, rocks are dropped off in a new place.

25. People change the Land Small Changes Large Changes
Digging a hole in your backyard
Large Changes
Trees cut down to build roads, stores, and homes
If trees are not replanted, soil can wash away
Ponds and swamps are drained
Dry soil left behind can blow away
Land is dug up to reach valuable rocks