Objective
• Students will have an
understanding of how rocks
change due to weathering and
erosion.
Vocabulary Words
• weathering – a processes at or near
Earth’s surface that cause rocks and
minerals to break down
• erosion – process of removing Earth
materials from their original sites
through weathering and transport
• rock cycle - a continuous process by
which rocks are created, changed
from one form to another, destroyed,
and then formed again.
How Break Down
• As you know rocks can
breaks down into smaller
bits.
• There are many ways
that a rock may break
down. There are broken
down by water, wind,
and other ways.
• When a rock breaks
down, it makes pebbles,
sans, silt, and clay.
How Rocks Change
• Have you ever been outside on a very windy day?
Sometimes, small pieces of sand or dirt may hit you legs
or face. It hurts!
• A rock begins to break down when the wind blows bits
of sand and pebbles on it. This is called weathering a
processes that cause rocks and minerals to break down
Changing Rocks
• Another way rocks
change into smaller bits is
by moving water.
• You may have help a
pebble in your hand that
feels smooth. That pebble
most likely was smoothed
by water in a stream or
by ocean waves. This is
called weathering a
processes that cause
rocks and minerals to
break down
Rock Breakdown,
Weathering, and Erosion
• Rocks can be broken
down into small pieces.
• Rocks break down into
pebbles, pebbles break
down into sand. Sand
breaks down into silt. Silt
breaks down into clay.
• This happens because of
weathering.
These are some ways weathering
can happen
Water, wind, and other ways of
these, water appears to be the
leader in changing the surface.
Weathering by Water
• Fast moving water causes rocks to hit one another
breaking them into smaller rocks.
Weathering by Frozen Water
• Frost Wedging – cracking of rock by the
expansion of water as it freezes in
crevices and cracks! Poor rock.
http://www.uwsp.edu/geo/faculty/ozsvath/images/frost%20wedging.jpg
Weathering by Root Penetration
Plant roots have to be strong to survive the elements.
Powerful plant roots grow into rock cracks and cause
fractures in rocks. This is another form of weathering.
Weathering by the Wind
• The wind blows and picks up small particles of sand
and blasts large rocks with the abrasive particles,
cutting and shaping the rock
More Weathering
• Land is constantly being changed and worn down
by wind, water, and ice.
original
level of the
plateau
Erosion
• Erosion – a
process of
removing Earth
materials from
their original sites
through
weathering and
transport
(movement)
Erosion
Remember: Erosion involves
removal and transport.
Erosion
Rain, wind, and streams are all
parts of erosion.
If a particle is loosened by
weathering, but stays put, its
just weathering. If it starts
moving, its Erosion.
Remember this!: You’ll be
quizzed soon!
Experiment
• Observation: The
earth’s crust is not flat
everywhere.
• Hypothesis/question:
How can sand show
weathering and
erosion?
• Use the Sand
Experiment handout for
directions.
Interactive Quiz
• http://www.nps.gov/webrangers/activities/rockpar
k/?id=22
Quiz Questions
1. Waves are crashing on a
sand beach.
1. As the sand is moving there
is definitely erosion; there is
also abrasion from the sand
gains colliding. Both
Quiz Questions
2. Water expands as it freezes
in the cracks of rocks.
2. This is frost wedging so it’s
weathering. There is no
mention of movement.
Weathering
Quiz Questions
3. Pebbles move down a
stream with the current.
3. There is probably some
weathering, but there is
definitely erosion. Erosion or
Both
Quiz Questions
4. a rock slide.
4. A rock slide could be both
weathering and erosion.
because the rocks
changed slide rock and
may hit other rocks..
Quiz Questions
5. A man shovels dirt to plant
a tree.
5.Since the man is
transporting Earth materials,
it’s Erosion.
Quiz Questions
6. A Glacier slowly moves down
a mountain.
6. A glacier moving down a
mountain would have both
weathering and erosion. Both
Quiz Questions
7. A tree’s roots grow into the
cracks of rocks.
7. A tree’s roots growing into
cracks of rocks would be
weathering. Weathering
Quiz Questions
8. A major volcano
erupts.
8. A major
volcanic eruption
would involve
both weathering
and erosion. Both
Quiz Questions
9. A boy takes out the garbage
for his mother.
9. Unless the garbage has
“Earth Material” or dirt in it
there is probably no erosion or
weathering. Neither
Quiz Questions
10. A shovel is left outside and
begins to rust.
10. The rusting of a shovel is
oxidation. This is chemical
weathering. Weathering
Video
• Rock Cycle Video
• https://www.youtube.com/watch
?v=D7WFeh30UpY
• Magic School Bus Rocks and Rolls
• https://www.youtube.com/watch
?v=YrC15uySkVE