Homework #0
Humphrey Geology 4880 Fall 2014
This is due next
Thursday (Sept 11).
Notes on all homework:
Try to couch your
answers at the appropriate level of accuracy that is implied by the question.
You are free to use data from any source or to make reasonable assumptions, but state what you
assume, or show
the data you use and give the source of the data. Be aware that data and ideas from the Web are
of highly variable quality, so if you use web sources you must include the
URLs. To do the homework you will have
to take 4 steps:
·
figure
out how to do the problem,
·
decide
on the data you need (if any),
·
collect
the necessary information,
·
and finally produce an answer, or
more likely, a discussion of a possible answer.
Note for these questions I expect an answer based on your thinking. If by chance you actually find an answer to a
question on the Web, I will expect you to explain the answer.
Your work must be neat, legible, and organized. I am not willing to wade through a mess and I will just give it back to you to re-do. You can work with others, but be aware that you will have to do similar questions on exams and quizzes, by yourself.
Often the
homework will include one or more questions that are quite hard. Warning,
usually the last one(s) are virtually impossible; however I expect an attempt,
since I want to see how you approach a difficult question. (Homework #0 does
not have an impossible last question, but all the questions should make you
think). Note that these questions are
mostly just to get you thinking in the wide ranging style that is needed to
solve a lot of geomorphic type questions. Actual answers only need to be (or
for that matter can only be) approximate. Since it is early in the course, these
questions do not require deep geomorphic knowledge, but do introduce several
concepts in geomorphology and environmental Geology.
Now the actual
homework
1
·
Part 1
How much rock is in Medicine Bow Peak? To make it more precise: what is the mass in kilograms
of Medicine Bow peak, above the elevation of Gap Lake (the lake between
Medicine Bow Peak and Browns Peak)? You
will need a topo map. TopoQuest on the web is a good place to
look. For other views Google Earth is a fantastic tool. [You will have to decide how accurately you
want to make this estimate. A general
rule of thumb: there is no point in making any measurement that is
significantly more accurate than any other variable in the problem. Part 2 asks
you to think about this a bit more]
·
Part 2 Now include an
educated comment on the likely size of the error in your estimate. Again, to be precise, answer these questions:
i.
Put
a % value on the potential size of the error.
ii.
What
are the 3 largest potential sources of error in your estimate, in order of importance. (Note
this is a straightforward question, but introduces the difficulty of answering
real world problems. Include your
working so I can follow your method)
2 Afternoon thunderstorms are
common at this time of year in Laramie.
How many raindrops hit the University during a typical Laramie
thunderstorm? List the assumptions you
had to make. (This is an exercise in reasonable assumptions)
3 Close to ˝ the surface of the
earth has been transformed by human activity.
One of the spatially largest activities is deforestation. Removing a forest tends to raise the albedo
of the land and thus more sunlight is reflected from the earth, which in turn
should cool the global climate. So could we reverse our current global warming
trend by cutting down trees?
Write a comment
on this idea: is it true (Note, please don’t talk about the ethics of this, I
am asking for a science answer)? Part
of the reason for asking this question is that you will probably find several
well written but opposite viewpoints in the literature and especially on the
web. I want to illustrate that many
simple questions do not have a single ‘correct’ answer. Note that there really is an answer; if we
did cut down all the trees, the temperature will either go up or down. But can we really know the answer now,
without cutting down trees?
4 Sand sized particles are common
in the weathered surface material of our planet. Sand is common everywhere that
physical (as opposed to chemical) weathering occurs, such as in rivers, beaches
and deserts. Indeed, virtually all surficial
deposits, that are not marine, have a strong peak in the sand size of the
distribution. Laramie overlies a large
indurated pile of sand, the Casper sandstone.
Why is sand so common? (or why isn’t there a continuum or smooth distribution of
sizes from big to tiny, instead of this preponderance of sand, and as it turns
out another peak in abundance in the silt/clay sizes?). Hint, note I said that sand is common where
physical erosion processes dominate.