# Project #2643 - Math and Science Homework

1.    Energy and Power (8 pts)
a.    (4 pts) The Kananaskis dam generates  93,500 MW-hr  of electricity per year.  Its capacity is 19 MW.  What percentage of the total capacity was actually generated?  How many average Alberta households would this supply?   (Remember:  the average Albertan household uses 600 kw-hr of electricity per month).
b.    (4 pts) Alberta coal power plants have the capacity to generate 6185 MW of electricity.  The actual amount of electricity that was generated in 2010 was 41,120 Gw-hr.  What percentage of the total capacity was actually generated?  How many average Alberta households would this supply?
[source: http://www.energy.alberta.ca/Electricity/682.asp]

2.    Radioactivity and Unit Conversion (6 pts)
Using the unit conversions below, convert the following quantities to hours of high altitude flight:
a.    Living in Denver for one year (27 mRem)
b.    Consuming 1 banana  (0.1 µSv) (convert to minutes of high altitude flight)
c.    Smoking heavily for a year - a smoker’s lungs are thought to absorb up to 20 rem in a year from Polonium in tobacco smoke (convert to years of high altitude flight)
100 rem = 1 Sv
1,000,000 µSv = 1 Sv
1000 mRem = 1 Rem
1 hour flying = .238 mRem of cosmic radiation exposure
[Sources:  http://www.nap.edu/openbook.php?isbn=0309051908&page=106, http://en.wikipedia.org/wiki/Banana_equivalent_dose ]

3.    Exponential Decay (8 pts)
The half-life of C-14 is about 5730 years.  It can be used to determine the number of years that have passed since an organism has died.
a.    (2 pt) Using a table (not the formula), determine how many years will pass before 1/32 of the C-14 is remaining.
b.    (2 pt) If only 30% of the C-14 is remaining, when did the organism die?
c.    (4 pt) Research:  the validity of C-14 dating relies upon there being a constant ratio of C14 to C14 in the environment of the organisms that are being dated using this technique.  Describe in your own words three reasons that C14 is not constant.  Describe one step that scientists have taken to resolve this problem.  Cite your sources (please cite a reliable source other than Wikipedia.  Any citation method is acceptable).

4.    Scientific Thinking (6 pts)
The mean surface temperature of the earth is positively correlated with the density of greenhouse gases in the atmosphere.  Carbon dioxide is a greenhouse gas.

Over the past 70 years, the level of solar activity as measured by the frequency of sunspots has been exceptionally high.   The mean surface temperature of the earth has also increased markedly since 1950.

GHG Hypothesis:  The increased mean surface temperature of the earth over the past half century has been caused by the increase of greenhouse gases in the atmosphere.

Sunspot Hypothesis:  The increased mean surface temperature of the earth over the past half century has been caused by the increase in solar activity.

Based only on the information provided in the above paragraphs, please state whether the statement is true or false (or that this cannot be determined), and explain your answer in a sentence or two.

a)    Increases in CO2 cause the mean surface temperature of the earth to increase.

b)    If the sunspots returned for a long period of time to their original lower rate, and the temperature of the earth continued to increase, this would provide evidence against the Sunspot Hypothesis.

c)    If the sunspots returned to their original lower rate and the temperature of the earth
continued to increase, this would prove the GHG Hypothesis.

 Subject Mathematics Due By (Pacific Time) 02/25/2013 12:00 am
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