Lecture Notes for Mr. English's World Geography Class

1. Earthly Changes
Within and On The Face of the Earth

2. Objectives
• Students will explain how scientists classify the
earth’s major physical characteristics.
• Students will describe the physical processes that
affect the earth’s crust.
• Students will explain how mechanical and
chemical weathering affect a place’s physical
landscape.
• Students will explain how the physical process of
erosion alters the landscape.

3. Vocabulary I
• core - the earth’s center, consisting of very hot metal that is dense
and solid in the inner core and molten or liquid, in the outer core
• mantle - a thick layer of mostly solid rock that grows in swampy
ground along coastal areas
• crust - the solid, rocky surface layer of the earth
• continent - any of the seven large landmasses of the earth’s
surface: Africa, Antarctica, Asia, Australia, Europe, North
America, and South America
• relief - the differences in elevation, or height, of the landforms in
any particular area
• weathering - the chemical or mechanical process by which rock
is gradually broken down, eventually becoming soil

4. Vocabulary II
• plate tectonics - the theory that the earth’s outer shell is
composed of a number of large, unanchored plates, or slabs of
rock, whose constant movement explains earthquakes and
volcanic activity
• erosion - the movement of weathered materials, including gravel,
soil, and sand, usually caused by water, wind, and glaciers
• sediment - particles of soil, sand, and gravel carried and
deposited by wind and water
• loess - fine-grained, mineral-rich loam, dust, or silt deposited by
the wind
• moraine - a ridge-like mass of rock, gravel, sand, and clay carried
and deposited by a glacier

5. Physical Characteristics
• Forces on & in the earth account for most of the
changes in the landscape
• Geology is the study of those changes
• Earth has many layers
• The core (both inner and outer), mantle, and
crust
• These do not exist in a
vacuum - changes in each
affect the others!

6. Spheres of Life
• Geographers see several spheres that describe life on
Earth
• Lithosphere - soil, rocks, landforms, and other surface
features
• Atmosphere - layer of air, water and other substances
above the surface
• Hydrosphere - water in oceans, lakes, and rivers, and
underground
• Biosphere - world of plants, animals, and other living
things that occupy the land and waters of the planet

8. Landform Relief
• As we can now see from earth, most of planet is water
(70%)
• Large landmasses between oceans are the continents we
live on
• By classifying landmasses by
their relative height, or their
relief, we can better
understand their impact on
our lives
• Mountains, plains, valleys
canyons, rivers,
peninsulas, etc.

10. Physical Processes
• Volcanoes
• Folds
• Plate Tectonics
• Continental Drift
• Seafloor Spreading
• Plate movement
• Ring of Fire

11. Surface Changes
• Changes below surface responsible for major
adjustments in the landforms
• Smaller, but more
frequent and quicker,
forces acting on those
landforms help to
shape and determine
their scope
• Broadly categorized
into weathering and
erosion

12. Weathering
• Process of breaking down rocks at or near the earth’s
surface into smaller pieces
• Two types: mechanical and chemical
• Mechanical weathering occurs when rock is actually
broken or weakened physically
• More often than not by water (freezing); frost
wedging
• Chemical weathering weakens or changes
the make up of the rock through exposure
to water and carbon dioxide that alters its
chemical make up; leaching/acid rain

13. Erosion: Water
• The movement of weathered material such as
gravel, soil, and sand
• Largely responsible for the creation of soil
• Moving bodies of water largely responsible for
transport or weathered material and creating
landforms; carries with it this sediment
• Effect is like sandpaper (carving the landscape
and breaking down sediment into smaller
particles)
• Ocean waves also play significant part in erosion

15. Erosion: Wind
• 2nd major cause of erosion is wind
• Following major droughts in the early 1930s,
most of Kansas saw dried up soil in great dust
storms
• Flip side is the loess that is deposited
onto new area
• Minerals and weathered material
that is broken down is picked up in
the wind and deposited

16. Watch video at
http://www.youtube.com/watch?v=xAQsGdcLl4c

17. Erosion: Glaciers
• Huge, slow-moving sheets of ice
• Carry dirt, rocks, and boulders with them as
they move; movement also wears down the
terrain
• Glaciers scooped out huge sections of earth as
they moved (millions of years) and left water
that filled them as they melted (Great Lakes)
• Also left behind ridge-like piles of rocks and
debris: moraines