Planetary Geology pdf - NASA

Purpose
In this experiment you will investigate the
process of wind erosion and deposition around features
such as craters and hills.
Materials
For each student group: 3 speed oscillating fan,
long table, chair, drop cloth, sugar, small ball (tennis
or racquet ball), drinking glass, metric ruler, pencil,
tape, ribbon or string (~15 cm long), 3 to 5 obstacles
(small rocks, keys, ruler, eraser, etc.).
Introduction
Wind is an important agent of gradation in many
arid and coastal regions of the Earth and on Mars
and Venus. During wind erosion, small particles are
moved in suspension, saltation, or traction. Very
small particles can be carried by the wind without
touching the ground until the wind slows or stops
and drops the particles. This is termed suspension.
Most sand (and sugar) sized particles are bounced
along the surface. This is termed saltation. Particles
Exercise Nine: Aeolian Processes
Name
Exercise
Nine Aeolian Processes
Procedure and Questions
107
too large to be picked up by the wind or bounced
along the surface may be pushed along the surface
by the wind or by the impact of particles in saltation.
This is termed traction. Eventually the particles
are deposited by the wind in some new location.
Wind erosion and deposition of particles result in
distinctive landforms, such as dunes and windstreaks.
Venus and Mars have wind related features
similar to those seen on Earth.
Sand or Sugar
Drop Cloth
Figure 9.2. Diagram of the experimental set-up.
Place the fan on the chair, centered at the end of the table. Make sure the center of the fan is even with the
surface of the table (see Figure 9.2). Direct the wind by tilting the fan towards the surface of the table at an
angle of 15 to 20 degrees from vertical. Tape a piece of ribbon or string on the end of a pencil. Turn the fan on
medium speed. Holding the pencil perpendicular to the surface of the table with the string along the table,
move the pencil around the table to locate the Òdead spotsÓ produced by the fan. Locate the area near the fan
where the air movement is greatest; this spot is where all sand piles should initially be placed.
Part One
Form a 5 centimeter high cone of sugar in the identified spot. Make an initial sketch of the top view and
side view of the cone in the space provided.
1. Initial Sketch (use Sketch Area A):
Turn on the fan at a speed (usually medium) that results in moderate movement of material. Leave the
fan on for three minutes. Answer the following questions while the fan is blowing.
2. How far down the table surface has the sugar traveled after one minute?
EG-1998-03-109-HQ Activities in Planetary Geology for the Physical and Earth Sciences