Physics 142 Recitation Questionnaire November 21, 2000
(If you need more space for writing, please use the back of this page)
Name samples of excellent student responses Reci. Section 8:30 11:00 12:30
Do your own work. Closed book and notes. Please do not talk to your neighbors for part II.
You may earn up to 6 bonus points
I. (3 pts) -- In a memo dated 11/9/00, the UNL Environmental Health and Safety Office uses this description of Gamma rays:
"Radioactive waves of energy that originate from change in the atom's nucleus."
Discuss this definition with two other people, and write your own short (2 or 3 sentence) critique. Be clear about what
seems reasonable in the definition, and what doesn't. Can you write a better description of gamma radiation?
Partners: ___________________________________ ____________________________________
This definition is incorrect in stating that gamma rays are radioactive
themselves; they are the results of the radioactivity of the radioactive
element. Gamma radiation is a photon released from the radioactive decay
of an element's nucleus.
II. (3 pts)
Dateline Paris, France -- Le Monde -- Ap
ril 21, 2000
(adapted from a true story)
The "mad cow" disease that seemed to infect the cattle of Great Britain has, so far, been prevented from
reaching France. In order to continue the "mad cow"-free condition of cattle in France, France's Bureau of
Health has banned the importation of all beef and dairy products from Britain.
British cattle farmers have claimed that this is unfair discriminatory practice. They have offered to have all
beef and dairy products irradiated by ionizing gamma radiation to kill any "mad cow" germs in their products.
They claim that such irradiated products would be completely safe for consumers in France, and that they will
be tasty.
The farming cooperatives of Frances have urged the French government to ban any such radioactive beef
and dairy products from their country. Importation of these products from England is likely to result in lower
prices for French consumers of beef and dairy products.
Because of the expertise you demonstrated in Physics 142 you have been hired by the French government to make a
recommendation on this dispute. What do you recommend? Be sure to explain your recommendation for people who
might not understand ionizing radiation as well as you do.
Irradiation, whether effective at destroying the "mad cow" prion (a
protein not a germ) is not going to be relevant. The issue here is that
people fear the beef becoming radioactive. Simply irradiating the beef
will not cause it to become radioactive, so this won't pose a threat to
consumers. However, if the radiation isn't effective at destroying the
"mad cow" protein, then "mad cow" disease could pose a threat. Before a
final decision on this subject is made the effectiveness of gamma
radiation on "mad cow" disease proteins would need to be determined.