Gas laws and gas behavior


mnething new. From the pwt. Gas Laws and Gas Behavior. Gas Laws and Syringes Revisited: Boyle's Law . . In the December, 1980 issue of THIS JOURNAL, p...
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mnething new From the pwt Gas Laws and Gas Behavior Gas Laws and Syringes . . Revisited: Boyle's Law In the December, 1980 issue of THIS JOURNAL, p. 885, the work of Derek A. Davenport involving the use of the hypodermic syringe t o study gaseous behaiior was reviewed: His work and similar demonstrations and experiments developed by others are wonderful sources for fun with gases in t h e classroom. Add to this collection Davenport's syringe experiments of Boyle's Law that appeared in "Tested Demonstrations," J. CHEM. EDUC., 56, p. 322 (May 1979). The experiments are easy to do, and typical data (all obtained in 5 minutes) are given. Gauge Pressure and Absolute Pressure On the same page as the Boyle's Law experiment mentioned above, Davenport describes some interesting (and fun) gas behavior using a standard tire pressure gauge and a side-arm test tube. Various pressure readings are made which show, "The sum of the gauge pressure and the residual pressure (in the same units) is sensibly constant!' "When the test tube has been completely evacuated, the gauge reading will be found to have increased by an amount equal to the atmospheric pressure." Who's Law?

"Boyle'slHooke's/Towneley and Power'shfariotte's Law," Robert M. Hawthorne, Jr., J. CHEM EDUC., 11, p. 741 (November 1979). "Chemistrv. .. like all the sciences. is filled with constants...orincioles. . and mathematical laws, many of which havesumeone's nameattached to them." Thestudent ofchrmi~try,knowing no brttrr. ~ s a p toast rume that the prrron named ir the prrwn who actually produced the number or formula that's on the page before him, an assumption often far from the truth. Probably no great harm is done in this way, as the substance of the law is more important than its provenance. Nonetheless, there are some interesting anecdotes connected with the formulation of laws. or the determination of constants. that can he

.A case in point is the gas pressure-volume relationship that we know as Boyle's Law, which has a very tangled origin indeed. It is from articles such as this one that the "s~ice"of the stow of cbemistrvcomes. The sienificanceof the oriori& of ouhlicationand of keeping a lab book is Gressed by the author, read the entire article to get the rest of the story. "The Fable: Laws are Mature Theories," Jack K. Homer and Peter A. Ruhha, The Science Teacher, 46,31 (February 1979). "At the heart of this fable is a fatal assumption about the relationship between laws and related theories: namely, that theories mature into laws by constant testing and confirmation." The authors present three familiar examples that show the fallacy of this common, naive misconception. Boyle's and Charles' laws are used as one of the examplesshowing ". _thatthe relationship between theories and laws is an exolanatorv one-not. as the fable insists. a maturational one." One rentlmg d r h article ~ and many