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J OURNAL oa CREMICAL EDIJCATION
DBCBMEBR, 1929
WINNERS IN FIRST "WHAT IS WRONG?" CONTEST The task of selecting the winners in the first contest1 has proved anything but an easy one. Particularly is this true as regards first place, for there were no perfect contributions. No one contestant observed and corrected every defect in the set-up pictured. Nearly every contestant offered some incorrect or irrelevant criticisms. And the best drawings did not always accompany the best written criticisms. However, we have not been reduced to the expedient of drawing straws. We have tried to arrive a t a fair evaluation of each contribution submitted, on the basis of a careful analysis of the problem. We have given the most credit to observations relating to the chemistry involved and to correct laboratory technic. We have allowed some credit
for criticisms directed a t minor or unintentional mistakes or omissions of the artist, provided they were based on actual scientific observation of laboratory conditions. Of this order were several criticisms of the form of the Bunsen burner flame, oi the omission of the clamp holding the test tube and of the lack of support for the gas-collecting bottle, etc. Criticisms of the draftsman's technic which did not involve scientific points were ignored as irrelevant. Erroneous statements were penalized. One of these occurred a number of times and evidenced a rather striking ignorance of the elementary principles of physics. It was to the eflect that the mouth of the gas-collecting bottle would have to be placed farther below the waterline in the trough in order that a column of water might be maintained in the bottle. Other things being equal, more credit was allowed for a correction which included a statement of the reasons therefor than for a bare assertion. For instance, Walter McCarty explained that "If a block of wood holding. 'See THISJOURNAL, 6, 1785-6 (Oct., 1929).
VOL.6. No. 12
Tns CHRM~STRY STUDENT
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P is placed as indicated it will be quite impossible to collect any 02.The P will unite with the 0% forming a gas which is soluble in water." We consider that a better criticism than the plain statement that "The block of wood and piece of phosphorus should he omitted." Weighing each contribution as carefully as possible in accordance with the considerations just outlined we have selected that of Eugene Harvey, of Martiusville, Indiana, as the best all-round paper. His criticism and drawing are reproduced here. W h e n potassium chlorate and sulfuric acid are mixed together and heated an explosion occurs. To obtain oxygen more slowly manganese dioxide should be thoroughly mired with potassium chlorate and heated. When these are mixed you will obtain a black powder. I n this experiment I see no reason for the phosphorus in the collecting battle. This should be used in another experiment. A Bunsen burner should not be left under a test tube as is shown in the drawing. I t should be held in the hand and moved along the tube. This drawing is out of proportion. The test tube should be smaller and the base of the ring stand should be larger. The test tube must have a clamp t o hold it on the ring stand. The stand is not balanced correctly. If a test tuhe were placed on a stand in the manner shown in the drawing, it would be unstable. A bottle put in a trough must be supported. The Bunsen burner as drawn shows no air holes in the collar. Without air the burner would give only a luminous flame. There should not be a line across the delivery tube where it enters the rubber tube, but the oxygen should have a free passage.
Some creditable suggestions made by other students were as follows: The clamp to hold the test tube should be placed somewhat nearer mouth of the tube than would be possible if the ring stand, upright, and the the test tube maintained the relative positions shown in the original drawing. It is neither necessary nor desirable for the delivery tube to extend so far into the test tuhe. The test tube as shown is too nearly horizontal. An angle of 3 5 O to 4-5' would be better. Facility in handling the apparatus (particularly in the event that water begins to suck back in the delivery tube) would be promoted if a rubber joint were inserted in the delivery tube. Several contributors advised the use of a hard-glass test tube, on the assumption that the presence of a lip on the tube drawn indicated that it was made of soft glass. Although that assumption is incorrect, they received some credit for the suggestion. Winners of the five one-dollar awards were: Dorothy E. Anderson, Syracuse, New York; Mildred Hockman, Martinsville, Indiana; Donald Mattox, Terre Haute, Indiana; Ansel E. Shoaf, Terre Haute, Indiana; Beatrice M. Moneypenny, Lowellville, Ohio.
