Planetary Geology pdf - NASA

Exercise
Nine Aeolian Processes
Instructor Notes
Purpose
The objective of this exercise is to demonstrate
the process of wind erosion and deposition around
surface features such as hills and craters.
■ 3-speed fan
Materials
■ 6-foot-long table (or longer)
■ chair
■ drop cloth
■ sugar (5-pound bag); very fine sand can be
substituted
■ small ball (tennis or racquet ball)
■ drinking glass
■ metric ruler
■ pencil
■ tape
Suggested Correlation of Topics
Aerodynamics, air and its movements,
arid lands, climate, deserts, environments,
erosion, landforms, meteorology, weather, wind
and its effects
■ ribbon or string (approximately 15 cm-long)
■ 3 to 5 obstacles, different sizes and types;
rocks, ruler, key, etc.
This exercise works well for groups of students.
In addition, it can be a demonstration by the instructor.
This exercise is only a general simulation of the
complex interaction of the wind and a planetary
surface. The wind produced by the fan has a ÒspinÓ
to it because of the fan blades. For increased simulation
accuracy, the wind can be stabilized by
Exercise Nine: Aeolian Processes
103
removing the ÒspinÓ. To stabilize the wind, an open
gridwork, such as toilet paper tubes glued together,
must be placed between the fan and the experiment.
Because the gridwork will slow the wind, as well as
stabilize it, higher fan speeds will be necessary for
material movement. Commercial three speed fans
may not have sufficient wind velocities. Sugar is
much easier than sand to move with the wind velocities
produced by a commercial fan. Both materials
are messy to work with, so have a dust pan and
broom on hand.
For more accurate simulation of the effects of
wind on planetary surfaces, it is recommended that
a wind tunnel be constructed. The directions for
constructing a wind tunnel are included here. The
construction of the wind tunnel is time consuming,
but can be used for quantitative experiments, or for
science-fair projects.
Wind Tunnel
Materials:
1. Wardrobe box from a moving company
2. 3-speed 50 cm box fan
3. Wind stabilizer (open ended milk cartons or
cardboard tubes glued together along their
lengths)
4. Base for inside box, approximately 15 cm
high and 50 cm wide
5. Masking tape
6. Clear plastic wrap (for the side ÔwindowsÕ)
7. Sand collection tray (such as a kitty litter
box)
8. Dark-colored posterboard
Construction:
Figure 9.1 shows the set-up for the wind tunnel.
Moving company wardrobe box (or similar size box
61 cm x 50 cm x 122 cm) is kept intact (do not
EG-1998-03-109-HQ Activities in Planetary Geology for the Physical and Earth Sciences
1.0 hours