What Not to Do in the Laboratory

An often overluuked aspect of teaching is the practice of showing students how nor to do certain things, such as nor canelling the threes in the frartinn'Yli w get %, or not toadd 'hand h toobtain K Thinnegativeaspen hapspecid imporlance in teachine lahrator, classes in rhemistry where fire hazards exist. dangerous chemicals abund, and the breaking of glassware can be a gainful andexpensive experience.

Over the osst few vears I have collected oieces of broken glassware in the laboratory and noted just what the student wna doins wrnhe at theiime of the accident. 1jurine the first laboratow period of the school year, the fragments and shards -~ - ~~~ " ~ ~~" are tastefully displayed on the laboratory benrheh'with notes of warn-i& beside each to explain what should not be dune. As an added bit of incentive, the price of each pwre is prominently displayed in red ink along with an old slightly used bandage.

For example, a thermometer, lacking bulb and mercury, is described: "A student pulled me out of a hot ail bath and attempted to cool me in cold water." A shattered graduated cylinder hears theepitaph: "A student tried to dry me out in a Bunsen burner flame." A West condenser whoae inner tube is punctured beyond repair hears the woeful tale: "A student tried to clean me out with a hrush several sizes too large." Perhaps the mwt dramatic exhibit of all is the top of a standard taoer flask with most evervthine else missing. The label succinctlv states: "Somebody heated a solution to dryness." ~~.~ . .. -

Although there is wme joking and hanter among the students as they read the labela and ubserve the fragments, the mesoage does sink m for mwt of them. In any event the display ufiers concrete evidence that laboratory safety rr a definite concern of the instructor.

St. Edwards's University Austin. Texas 78704

Thomas MeCullough, C.S.C.

Volume 53, Number 12, December 1976 / 7(H