Planetary Geology pdf - NASA

1. Sketch of cone
2. Answers will vary, depending on fan speed
and material (sugar or sand) used. Usually
travels entire distance of table and beyond (a
meter or more).
3. Answers will vary, but may see a sheet of
sugar/sand with ripple-like features developing
perpendicular to the wind direction.
4. Answers will vary, depending on fan speed
and material used. Usually 1/3 to 1/2 meter
for the initial bounce. The second one is shorter
(less energy).
5. Answers will vary, depending on fan speed
and material used. Usually a few centimeters.
6. Sketch (NOTE: sketches are not provided
within this answer key, as the variation in fan
velocities will control the speed of erosion and
deposition).
7. Sketch
8. Erosion occurs at the front and sides of the
cone.
9. Deposition occurs behind the cone.
10. The sketch below represents the aerodynamic
characteristics of a crater when wind blows
across it from left to right. Experiments to
visualize this model were done at the NASA
Ames Research Center. For a cone, the reverse
flow (seen within the crater) does not occur.
11. Sketch
Point of
Attachment
Exercise Nine: Aeolian Processes
Reverse Flow
Reverse Flow
Answer Key
105
12. Depending on the shape and positioning of the
obstacles, sugar will initially pile up against
the obstacle (on the front and sides), some
sugar will also be deposited behind each
obstacle. With time the sugar will be removed
from the front and sides, but will remain in the
lee of (behind) each obstacle. For discussion,
talk about windbreaks, such as snow fences,
and other obstacles man puts in the path of the
wind to control drifting sand and snow.
13. Sketch
14. Sketches, see answer 10 above for wind movement
arrows.
15. Students should see sugar within the crater
moving from the back of the crater towards the
front (reverse flow). Once the back rim of the
crater has been removed by erosion this
motion will decrease dramatically and may
not be observed by the student.
16. Sketches, see answer 10 above for wind movement
arrows.
17. Answers will vary, should be the same for both
crater shapes.
18. a. Answers will vary, but should have produced
something similar to the windstreaks
seen in the figure (most likely during Part
Two).
b. The average prevailing wind has come from
the east (from right to left).
c. The bright crater tails are most likely depositional
zones of bright surface materials.
Shadow Zone
Vortex Core
Deposition
EG-1998-03-109-HQ Activities in Planetary Geology for the Physical and Earth Sciences