James M. Thorne and Kenneth Lee Matheson Brigham Young University Prove. Utah 84602
II
A Simulated Research Experience for Chemists and Non-Chemists
News ilem:..Hundreds of sheep lir d ~ n don desert gmzmg land in the Wrstrrn llnlted States. Har this herd heen dreimnted 1," a nrw leak g,f military nerve gas? It happened once befor? in 1968 ( 1 1 . A government spokesman says &the sheep were killed by the weed Halogeton which was found in all their stomachs. Some unknown toxin apparently entered the blood stream and deposited crystals in the kidneys. The crystals perforated the kidneys and caused the death of the sheep." This is t h e introduction given t o students who a r e then assigned t o extract t h e toxin from t h e weed Haloeeton d o m era&, t o determine t h e chemical formula of th; toxin, and t o suepest antidotes if oossihle. Because t h e toxin turns out t o be'tYhe simple compound sodium oxalate, which comprises from 10-30% of t h e plant, students find t h e assignment is relatively easy i n spite of their initial feelings of inadequacy. A t BYU, eight adults with practically no formal training i n chemistry were able t o complete t h e task i n 8 hours of laboratory work interspersed with 3 hours of lecture. They found t h e practicality a n d puzzle-like nature of t h e problem very stimulating and, after t h e usual frustrations, they showed great pride i n accomplishing this apparently difficult assignment. B u t more important, they experienced many of t h e same feelings a n d performed many of t h e same activities shared by researchers in chemistry. T h e y relied on information from the literature, designed and performed experiments, participated in teamwork, and did all of this under conditions of limited time and limited resources. Of course this project is n o t truly research since much is already known about Halogeton toxicity. Halogeton was accidentally introduced from Asia or Russia about 40 years ago, and it has spread t o several million acres of cold desert (2).T h e plant has good nutritive value-similar t o t h a t of alfalfa (3), b u t when sheep are suddenly brought into a n area where they eat only ~ a l o g e t o nt h e microorganisms of t h e rumen cannot detoxify t h e oxalate fast enough t o prevent t h e death of a n animal (4). Forced feeding of enough dicalcium phosphate t o react with all of t h e oxalate ingested by a sheep may prevent death, b u t large amounts are required a n d i t must be administered within 4 hours of oxalate ingestion (5). Better protection is afforded by preventing sheep from eating too much Halogeton too fast (6).
Necessary Concepts Students who have passed a general chemistry course will have adeauate ~~~. backeround to solve this oroblem without learnine additional concepts. However, everyone needs access to a good chemistry text, and everyone nerds tu know how to use theMerrklnder and a hnndho
