Predictably the tourist said of course not it might

and jumping up-and-down vigorously. Predictably, the tourist said "of course not, it might fall over."
Dr. Alley then pointed out the many places where rocks clearly had fallen off the cliffs and moved
downhill, at which point the tourist quickly switched his opinion to the "down-cutting" river
explanation, with the ranger thoroughly enjoying the show.
Points Earned: 1/1
Your Response: D
1
4.
Sam Ascah is standing on sand and gravel in a pothole, where a stream swirls during the short but
intense thunderstorms of Zion National Park. And next to that stream, the other picture shows the
sandstone and the hang-on-so-you-don’t-fall-over-the-cliff chain along the trail. A likely
interpretation of these features is:
The Park Service carefully cut little grooves behind the chain before they hung it, so that it
would look cute and slide well, and they cut the potholes so that hikers would have something
to look at.
A.
The potholes and the grooves behind the chain were gnawed by giant marmots. B.
The grooves behind the chain have been cut over decades by motion of the chain as hikers
grabbed it, and the potholes were cut by water swirling rocks around during the rare floods
over much longer times.
C.
The stream swirled rocks around and cut the potholes, and even bounced up the cliff to cut the
notches behind the chain.
D.
The potholes and the grooves behind the chain were gnawed by giant beavers. E.

The chain really has hung there for decades, and has been scraped against the cliff dozens of times
per day each summer, slowly wearing into the easily broken sandstone. The stream does swirl rocks
around and slowly wear down the potholes. The potholes were there beside the cliff when the trail
was established, and haven’t changed too much over decades.
Points Earned: 1/1
Your Response: C
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RockOn #5
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Points Awarded 13
Points Missed 1
Percentage 93%
Rising air expands and cools; sinking air is compressed and warms. Typically, the size of the
temperature change is:
1.
3 A.
o
F/1000 ft change in elevation.
5 B.
o
F/1000 ft change in elevation going up, and 5
o
F/1000 ft coming down.
No change if evaporation of clouds is occurring, and 5 C.
o
F/1000 ft change in elevation if no
changes are occurring in clouds.
No temperature change occurs when air moves vertically. D.
5 E.
o
F/1000 ft change in elevation if condensation or evaporation are not occurring; 3
o
F/1000 ft
change in elevation if condensation or evaporation are occurring.
The expansion of air on rising takes work, which cools air, at about 5
o
F/1000 ft, and the compression
on sinking reverses this. But, if rising air cools enough, further cooling causes water to condense, the
heat given off by the condensation partially offsets the cooling, leaving about 3
o
F/1000. If there are
clouds in the air as it sinks again, the air will warm about 3
o
F/1000 ft, with some energy being used to
evaporate the cloud water rather than to warm the air; once the clouds are gone, then the full
5
o
F/1000 ft warming occurs.