Radioactivity

Part 1: Answer the problems found below.  For each one you can use a hand-drawn chart like this one, or the table that is attached, but you MUST show your logic for each project.  Just writing down the answer will not get you credit.

1) The half life of iodine-131 is 8.040 days. What percentage of an iodine-131 sample will remain after 40.2 days?
2) The half-life of thorium-227 is 18.72 days How many days are required for three-fourths of a given amount to decay?
3) If you start with 5.32 x 10⁹ atoms of Cs-137, how much time will pass before the amount remaining is 5.20 x 10⁶? The half-life of Cs-137 is 30.17 years.
4) The half-life of the radioactive isotope phosphorus-32 is 14.3 days. How long until a sample loses 99% of its radioactivity?
5) U-238 has a half-life of 4.46 x 10⁹ years. How much U-238 should be present in a sample 2.5 x 10⁹ years old, if 2.00 grams was present initially?   (Hand this in individually)

Part 2:  Create a video public service announcement that tells the class about one of the following.  I would prefer you spread out across all the topics, rather than several people doing the same thing.

• Irradiation of spices using cobalt-60
• Radon is a big problem in Iowa
• Cs-133 atomic clock uses
• Iodine-131 uses
• Americium-241 for gauging plastic
• Americium-241 smoke detectors
• CT vs. PETscans using C-11, N-13, or O-15
• Uses of Technicium-99m
• Fresh food irradiation using cobalt-60 to kill ecoli or other bacteria.

The following information must be present in your video clip:

a.  What type of decay is going on?

b.  What is the half-life of the object, and how long will it take for 99% to disappear

c.  How can we protect humans from this type of isotope when we don't want to be exposed to it?

d. How are force or momentum used in this process?

e. How valuable is this process?

f.  How is the use of this radioactive tool comparable to a non-nuclear option.   Pick two similarities and two differences.

g. Why is radioactivity all around us?   And what's the difference between radioactivity and antimatter.

Upload your video to a youtube account and share with me.

Grading Rubric

Content correctness:  10 points

Entertainment value:  10 points

Use of media to enhance presentation: 5 points

Involvement by all members of group:  5 points

Title or Credits, as appropriate:  5 points