The Physical World Shaped from the
A blanket term for those processes which
operate on or close to the surface of the Earth
and which involve weathering, mass
movement, fluvial, glacial, and coastal
processes. The term is normally used in
contrast to endogenous processes, whose
origin is within the Earth.
• Most rocks are broken down by wind, rain,
and the sun in a process called Weathering.
• Weathering causes huge problems to the
physical earth and to human creations such
as roads and buildings
• The type of weathering and the speed at
which it occurs depends on many different
Factors that Effect Weathering
• The make up of the Rock
• The climate
• The Soil
• The Vegetation
• Rock breaking down due to the continuing
cycle of stress and strain
• This type of weathering usually occurs in
deserts such as the Sahara Desert
• Heat and Cool process breaks down the
rock (Onion Weathering)
• If a rock has many cracks water may seep
into the rock and freeze during the night. In
time, bits of rock begin to break off because
water expands by about 8% when it forms
ice and this puts strain on the rock
• Water is needed for Chemical Weathering
to take place-whether in the form of rain or
from dampness in the air
• Rocks are made up of one or many different
minerals and it is these which are changed
• Hydrolysis-Water reacts with minerals and
breaks them down.
• Carbonation and solution- Water reacts with
carbonate minerals to make them soluble.
Oxidation within Rocks
• Oxidation occurs when oxygen from
the air is added to metals in rock to
Vegetation and Weathering
• a combination of processes in which the
materials of the earth's surface are loosened,
dissolved, or worn away, and transported
from one place to another by natural agents.
• Glaciers, running water, wind, and ice are
the natural agents that cause erosion and
transport the effects of it
• A permanent body of ice, consisting largely
of re-crystallized snow, that shows evidence
of down slope or outward movement, due to
the stress of its own weight.
Streams and Rivers
• These water systems are vital in moving rainwater
from land to sea, but are far more important as
geological agents, transporting and depositing
sediments as they flow.
• It is estimated that each year, streams and rivers
move about 1.5 billion tons of sediment from land
to the Earth's oceans. By shifting such great
masses of earth, streams and rivers become
sculptors of the land
Rivers rarely maintain a straight route as they
travel to larger rivers, lakes or oceans -- most
make a series of bends and smooth loops that
snake across the landscape. The bends, known
as meanders, reflect the way in which a river
minimizes resistance to flow and spreads
energy as evenly as possible along its course.
• The intense energy accumulated as water rages,
bubbles and flows down a stream is drastically
dampened when the water enters a calm lake or
quiet ocean bay. As the speed of the flow slows
rapidly, its ability to move Sediment is also
hampered. The water belches out its load in the
form of a delta, so-named because the deposit can
develop a crudely triangular shape that resembles
the Greek letter "delta."
• Ocean meets land in a turbulent zone of
energetic activity. While sediment is
flushed and deposited into the sea by in-
flowing rivers, waves that have traveled
hundreds, or even thousands, of kilometers
across the open ocean erode and re-work the
Over time, the net effect is substantial: the
shape of a coast changes, often slowly, but at
times rapidly. During storms, for example,
powerful surf will swiftly erode deposited
sediment from the shore. In calm weather,
sediment will deposit faster than it erodes and
in turn will widen the existing shoreline.
• Blown sand amongst other weathering
agents causes erosion by abrasion.
• Weaknesses are picked out and in time only
the most resistant sections are left: often
causing abnormalities in shape.
Wind and Rocks
Conclusion on Exogenous
• The fact is that many resources can be
viewed as positive resources for our world,
and others can be viewed as dangerous!
• It is even possible that a resource can be
considered both, as in the case of water.