3.  Land has many different shapes.  A natural land shape or feature is called a landform.  When you describe the landforms around your town you are describing topography.  Topography is all the kinds of different landform in a certain area.

4. These are the Rocky Mountains. This is a tall, jagged peak mountain that rises thousands of feet above the Surrounding land.

5. The Appalachian Mountains in this picture are lower and more rounded. They are still thousands of feet tall, but are much lower than the rocky mountains.

6. So even though the two mountain areas are very similar landforms, their topographies are very different!

7. The topography of volcanoes differs in another way. Volcanoes usually occur as individual mountains, not in ranges. They may have steep sides or rounded slopes.

8. Hills are landforms that are like mountains, but not as high. Most hills have rounded slopes.

9.  Not all landforms have slopes.  A plain is a large, flat landform with little relief.  Relief is the difference in elevation between high and low places.

10.  Glaciers are large sheets of ice.  As they move, they change the land beneath and around them.  Moraines are long, low hills formed by glaciers.

11.  As moving ice scrapes the land beneath it, rocks and other materials are picked up and carried away.  This material is deposited somewhere else, when the glacier melts.

12. Q. How can you tell a moraine from a hill Moraines have rock, sand, and clay. These things are deposited together. Other landforms made by glaciers are glacial grooves. Glacial grooves are scrapes and scratches in the rock made as the glacier moves along land.

13.  Landforms of sand are easily shaped by wind and water.  These landforms are known as sand dunes.  Wind can change a sand dunes shape or even it’s entire location.  Sand dunes can move as much as 100 ft. in one year.

14.  Water also reshapes beaches, forming barrier islands and san spits extending out into the water from the ends of many islands.  Sand spits and barrier islands are long, narrow piles of sand that help protect the mainland from the wave erosion.

15.  A mesa is a tall, flat-topped rock feature, that forms when water and wind erodes the surrounding rock.  Canyons are deep valleys with steep sides. They are found throughout the Southwest. The water and wind has carved the land away. The Grand Canyon is an example.

16.  P. 255

18.  Over time, sand wears away rock by breaking it into smaller pieces.  This process is known as weathering.  Step 1: Weathered rock (sand) is carried away by wind.  Step 2: The pieces keep moving as long as the wind is blowing.  Step 3: The wind stops and the sand falls to the ground.  Step 4: These piles grow.  Step 5: They slowly become sand dunes.

19.  Are found in many places: deserts, beaches, lakeshores, etc.  Some desert dunes are as high as a 30-story building.  All dunes help protect land during storms.  However, dunes can cause damage to buildings and roads if pushed by strong winds.

20.  Moving water can change Earth’s surface by carrying soil and small pieces of rock away from landforms.  Moving water can dig a canyon or change the path of a river.  A rapidly flowing river erodes its banks and its bottom.  Eroding banks makes the river wider.  Eroding the bottom makes the river deeper.

21.  The moving water then carries sediment downstream.  When the water slows down, sediment is deposited.  Deposits on a river bank, makes it narrower.  Deposits in the bottom make the river shallower.

22.  Moving wind and water has energy.  The faster it moves, the more energy it has.  But, all moving water, even a gentle rain, can erode some sediment.  When rain falls on bare soil, it splashes away soil.  As it runs downhill, it gains speed and energy.  Over time, water erosion can leave gullies, or ditches in the ground.

23.  Ocean waves also cause erosion.  Waves carry away broken bits of rock and sand.  Piece by piece, cliffs get steeper.  When cliffs eventually overhang, the entire cliff can collapse into the oceans.

24.  Ocean waves change landforms in another way, also.  Each wave also brings more sand to the beach.  This is deposition.  As the water slows down, it loses energy and the larger pieces of sediment fall out and settle to the bottom.

25.  Flooding can deposit sediment near a river.  When you have heavy rains, rivers flood their banks.  When the rain stops, the water returns, but the sediment it carried is deposited on the land.  This sediment is rich in nutrients for plants.  These areas are called flood plains and are great for farmers, but awful for living.

26.  Rivers deposit sediment at the mouth, the place where it empties into the ocean.  The flow of water slows as the river reaches the ocean.  Much sediment is deposited, forming a delta.  A delta is an area of new land at the mouth of the river.

27.  Ground water can weather and erode soft rocks.  Underground erosion causes caves to form.  If the roof of the cave collapses, under the weight, it creates a large hole.  These holes are Sink Holes.  Most sinkholes are found where limestone is common.

28.  Gravity also helps land-changing processes to occur.  Landslides happen very suddenly, especially after heavy rains or earthquakes.  A land slide is when soil, mud, and rock move quickly down a slope.

29.  Ice can change landforms by weathering rocks.  Rocks have tiny cracks and holes  When it rains, these fill with water.  If it is cold the water freezes, and expands, making cracks bigger.  The next time it rains, more water gets in, and the process continues.  Over time, the rocks are broken into smaller pieces, until there is only a pile of sand.

30.  Ice can also change landforms as glaciers.  Glaciers can shape landforms by erosion and deposition.  Glaciers follow river valleys down a mountain.  As a glacier moves, it changes the V-shaped valley into a U-shaped valley.  Glaciers deposit the sediment when they melt.  New York is an island formed from the deposition of a glacier.

31.  Plants can cause weathering and erosion.  When a seed germinates on a rock, the roots grow in small cracks.  As the roots grow they cause the cracks to grow.  Some plants even release chemicals into the soil.  These chemicals help weather rock by dissolving certain minerals.

32.  Plants also preserve and protect Earth’s landforms.  Roots hold soil and sand in place, and prevent erosion by wind and water.  Farmers often plant cover crops, to help return nutrients to the soil and stop erosion.  At the beaches, plans keep sand dunes from blowing away.

33.  P.265

35.  The center of the Earth is 4000 miles down.  The Earth has 4 layers-  1. crust  2. mantle  3. outer core  4. inner core.

36.  The Crust is solid rock.  The Mantle is also a lot of solid rock, but there is also soft rock, like melted candy.  The Outer Core is liquid iron (not rock), and is liquid.  The Inner Core is iron and nickel, and is solid due to great pressure.

37.  The Earth’s crust is divided into plates.  Plates are puzzle pieces that fit together.  There are 10 major plates.  Plates “float” on the mantle.  As the rock flows, the plates move.  This causes changes in the Earth.

38.  When 2 plates move past each other, energy is released and the ground shakes.  An earthquake is movement of the ground caused by a sudden release of energy in Earth’s crust.

39.  The place within the crust where the energy is released is called the focus.  The greatest damage will occur directly above the focus.  The point on the Earth’s surface that is directly above the focus is called the epicenter.  Earth quakes are caused by 3 types of plate movement: 1. plates pushing together 2.plates sliding past each other 3. plates pulling apart

40.  Earthquakes occur along a fault, or break in the crust.  Most faults are found near the edges of plates.  Faults develop as plate movement bends and cracks the crust.  Earthquakes caused by pushing plates are strong.  Earthquakes caused by pulling plates are weak.  Earthquakes are measured by their magnitude, or amount of energy released.  It is reported on the Richter Scale.

41.  An earthquake measuring 2.0 is too small to be felt.  An earthquake measuring 6.0 or more can cause a lot of damage.

42.  Melted rock beneath the surface of the Earth is magma.  Magma forms in places where plates push against or pull away from each other.  Magma is less dense than solid rock, so it pushes upward.  A vent is an opening in the crust where magma can come out.  When magma reaches the air, it is called lava.  A volcano is a mountain made of lava, ash, or other materials from eruptions.

43.  Composite Volcanoes- wide with steep slopes. Made of alternating layers of lava and ash. (Mt. St. Helens)  Shield Volcanoes-broad with gentle slopes. Form from lava that easily vents. (Hawaiian Islands)  Cinder Cone Volcanoes- tall and narrow, steep slopes. Made of rock, ash and other materials. Are not made of lava. (Paricutin)

44.  Mountains are the tallest landforms.  They form where the crust is crumpled and pushed up.  The edge of the denser plate sinks, and the less dense plate pushes up.  If they are the same density they both push up.