Wednesday, April 16, 2008 (my birthday!)
Announcements:
- The Web Projects are due next
Monday. Let me know the URL for your group's website. Peer
evaluations of the websites will begin next Tuesday.
- Our next exam will be held next Monday and will cover chapters 13 - 17.
- Our final exam is scheduled for 8:00 am on Friday, May 2.
If you intend to take this exam at another time, you first need to get
a permission slip from your academic dean.
Assignments:
- Read Chapter 17 and answer the recommended homework questions.
- Continue working on your Web Project, and send me the URL for
your group's website once it is posted.
- For 2 days worth of class participation credit, you are
encouraged to create your own personal website in your UNC server space
(www.unc.edu/~onyen). This website does not have to be anything fancy,
just something other than the current default message that appears for
a blank webpage. Once you have completed this task, send
me your URL.
Chapter 16 review - answers to student questions
- How
can both fusion and fission (opposite reactions) both give off energy?
- The answer lies in the nuclear binding energy curve, Fig. 16.4.
- Why
is there more energy associated with a neutron and proton separated
than together? - Because the strong nuclear force is attractive, so it
takes work to separate these nuclei. This is similar to the
larger gravitational energy associated with two massive objects that
are separated from each other.
- Why do separated nuclei weigh more than a whole nucleus?
- I don't understand why the nucleus continues to split apart; doesn't that make it weaker?
- What happens to the He created after fusion of hydrogen? Is there a large buildup of He?
- Is naturally occuring U-235 used for anything or is it not worth the effort given the abundance of U-238?
- Which nuclear reactions are most important and that we need to know?
- How much stuff goes into a nuclear reactor? Do you have any demos?
- I don't understand Bohr's liquid drop model for nuclear fission.
- Why is nuclear fusion not feasible at this time?
- How does a nuclear reactor work?
Chapter 17 - The Energy Challenge
This chapter synthesizes concepts from many of the previous
chapters. You are now in a position to make educated decisions
about the energy issues facing our society. This evaluation
process is not trivial (it requires the highest level of cognitive
reasoning), but our future does depend on the choices we make.
The worldwide consumption of energy is increasing exponentially with a
large fraction depending on oil, which has a supply that is expected to
peak and decline within the next decade or so. What do you
believe is the best solution for this energy crisis?
Which alternative energy source do you believe is the best option for
the future?
Should tax credits and penalties be imposed to influence the economic
pressure towards alternative energy use?
Table 17.3 lists the costs and benefits from coal and nuclear
power. Which of these energy sources is the best option?
What can you do to positively influence our world's energy crisis?
Energy prices are directly tied to food prices and population growth. The World Bank and International Monetary Fund (IMF) are meeting now
to adress the concerns about skyrocketing food prices and the impact
they are having on the millions of people who live on less than $1/day.
While biofuels are one alternative to using oil, they are contributing to higher food prices.
Since population growth is part of the problem, should other countries follow China's example of a one-child policy?