2. What is Erosion?
Erosion is defined as removal of
rocks and soil by wind, water, ice and
gravity.
Wind, water, ice and gravity are also
known as the agents of erosion.
3. Weathering vs. Erosion
Weathering involves two processes
[physical, chemical]
that often work together to break down
rocks. Both processes occur in place.
No movement is involved in
weathering.
4. Wind Erosion
Wind can play a role by carrying material
(especially sand and clay) from one place to
another.
As the wind blows, it picks up small particles of
sand/sediment and blasts large rocks with the
sand/sediment, cutting and shaping the rock.
The intensity of wind erosion is determined by:
Sum (amount of sand)
Speed
Slope
Surface
6. Water Erosion
When rain falls to the Earth it can evaporate, sink into the ground, or flow over the
land as Runoff. When it flows over land, erosion occurs. Runoff picks up pieces
of rock and "runs" downhill cutting tiny grooves (called rills) into the land.
How much erosion takes place is determined by the:
Sum (amount of water)
Slope
Speed
Surface
8. Ice Erosion
Glaciers wear down the landscape; by picking up and carrying debris
that moves across the land along with the ice.
Glaciers can pick up and carry sediment that ranges in size from sand
grains to boulders bigger than houses.
Moving like a conveyor belt or a bulldozer, a single glacier can move
millions of tons of material!
How much erosion takes place is determined by the:
**Sum (Glaciers are massive!)
Slope
Speed
Surface
10. Gravity Erosion
Gravity Erosion is better known as Mass Movement
and is defined as the transfer of rock and soil
downslope by direct action of gravity without a
flowing medium (such as water or ice). Some of the
best examples of Mass Movement are:
Creep Rock fall Slump
Landslides Avalanches
12. Karst
A type of landscape where caves are
common.
The land has different sized blocks of
limestone. These fractures are where the
water seeps in, dissolves the stone, and
forms caves.
13. How does this effect us?
Humans are constantly
influencing the nature of
our landscapes.
HOUSES, ROADS,
BUILDINGS,
DEVELOPMENTS,
CANALS, etc., all
change the shape and
appearance of the land.
14. Erosion Lab
Preparation
Put notes where you can see them, but out of the way of water and mud.
Procedures:
Person 1 gets a plastic container and brings it to the dirt supply for 1 small shovelful of dirt at one end of the plastic
container.
Person 2 gets one pipette for each member of the group and something to tilt slightly the plastic container.
Person 3 gets a cup and fills it up with water.
Set up your container so it flows evenly down to the low side of the container. (Slanting in more than one direction can
cause water to accumulate in corners and cause unnatural features.)
Add 100-150 mL of water to the lower end of the container to make a small lake.
Everyone gets one pipette which can be used to drop (not squirt) on to the “mountain”. You have 20 minutes to do this.
Make note of erosional features because some features, such as sinkholes, slump, and landslides are very difficult to
identify after they happen. Feel free to experiment with height of the drop.
After 20 minutes, have students answer the following questions:
Cleanup:
Person 1: Puts dirt in disposal as directed and rinses/wipes the container.
Person 2: Returns pipettes and wipes up any mess around lab area on floor
Person 3: Returns beaker and dries up any water around lab area on desk
15. Weathering and Erosion Lab
Procedures; Step 1
Make a pile of sand in the middle of the pan.
Place pebbles on the surface of the new hill, and hypothesize what will
happen.
Now lightly blow across the sand and pebbles with the straws.
Make a “sand mountain” by piling sand up on one side of your pan.
Hold the ruler in the mountain so that the sand covers up to the 10
centimeter mark.
Make a “rain cup” by taking one of your small cups and poking holes into
the bottom of the cup with your pen or pencil.
Hold your “rain cup” over your mountain and fill the other cup with water.
Pour the water from the second cup into your “rain cup” – the water will now
“rain” on your mountain.
After the rain has stopped, measure the height of the remaining sand and
record that number below. Explain where some of the sand went to and
16. Weathering and Erosion Lab
cont.
Step 2;
Make a second mountain exactly like the first.
Using the popsicle sticks, build a dam on one side of the mountain.
Hypothesize what will happen when this new mountain is “rained” on.
Now “rain” on your new mountain and record the height below. Was your
hypothesis correct? Explain your results below.
17. Weathering and Erosion Lab
cont.
Step 3;
Make a chemical weathering chamber by adding a piece of chalk to the last
small cup and filling it ½ full with vinegar.
Put the lid on your chemical weathering chamber and shake it vigorously
for ten minutes – You might want to take turns with this one.
Hypothesize what will happen to the chalk.
