Apparatus, teaching

The value of fractional distillation in the examination of essential oils cannot be overestimated. The various fractions may be examined and their specific gravities, optical rotations, and refractive indices determined. The combination of these figures will often give the experienced analyst the most useful information and save him many hours needless work. Experience alone, however, will teach the chemist to make the fullest use of the results so obtained. In most cases distillation under reduced pressure is necessary on account of the risk of decomposing the various constituents of the oil. The use of a Briihl receiver (or any similar contrivance), which is easily obtained from any apparatus maker. 

Julian stayed at Harvard four years on minor fellowships, and then went back south to teach at the West Virginia State College for Negroes. His laboratory had next to no apparatus. He was the one-man chemistry faculty, laboratory storekeeper andjanitor as well (de Kruif, 1946). Julius Stone, Jr., a Harvard classmate and the son of a leading banker and industrialist in Columbus, Ohio, came to Julian s aid. With Stone s financial backing and a General Education Board fellowship, he went to Vienna (de Kruif, 1946) and received a Ph.D. at the University of Vienna in 1931. Julian considered himself to be only the third native-born black to earn a Ph.D. in chemistry (de Kruif, 1946). 

Classical laboratory, manual methods conducted on a macro-scale where sample quantities arc in the range of grams and several milliliters. These are the techniques that developed from the earliest investigations of chemistry and which remain effective for teaching the fundamentals of analysis. However, these methods continue to be widely used in industry and research, particularly where there is alarge variety of analytical work to be performed. The equipment, essentially composed of analytical balances and laboratory glassware, tends to be of a universal nature and particularly where budgets for apparatus are limited, the relative modest cost of such equipment is attractive. 

Teyler s Museum at Haarlem, The Netherlands, retains one of the most complete collections of scientific instruments amassed by an institution for the purpose of teaching and research. An earlier volume, published in 1973, elucidates the collection acquired by Martinus van Marum between 1784 and 1837. The current volume, compiled by the same author, deals with the period c. 1840 to 1915.88 A somewhat smaller proportion of the 454 entries deal with chemical apparatus compared with the earlier period, but what is to be found is not without interest, including an extensive set of equipment for testing the quality of town gas. 

G. L E. Turner, The Practice of Science in the Nineteenth Century Teaching and Research Apparatus in the Teyler Museum, Teyler Museum, Haarlem, 1996. 

There had been isolated British chemists of distinction in the eighteenth century We have encountered some of them, most notably Joseph Priestley and Joseph Black. Priestley had taught in a dissenting academy, and the members of the private and informal Lunar Society of Birmingham had supported his research. He had had to teach himself the techniques of research and to devise a good deal of his own apparatus. He did not have students or assistants... 

Lunge s article is referenced in [20], Another article from the Chicago conference explicitly proposes lectures on basic operations a textbook devoted not to products but to processes, apparatus, and methods of treatment and a laboratory to illustrate points and teach the art of making mistakes on the small scale, Henry Pemberton (Philadelphia), The Education of Industrial Chemists, J. Amer. Chem. Soc. 15, 627-635 (1893). That unit operations were abundantly being practiced is obvious and has been emphasized by Martha M. Trescott, Unit Operations in the Chemical Industry, pp. 1-18 in W. F. Furter, ed.,.4 Century of Chemical Engineering [17], and in her book [11],... 

The control that is needed to achieve good reproducibility of results from one laboratory to another extends from the composition and structure of the catalyst and the conditions of its pretreatment to the apparatus in which this, and the ensuing catalytic reaction, are performed. Experience teaches that factors such as reactor dimensions and the material of its construction are critical for reproducibility, especially in the case of exothermic reactions, as shown in Section 11.1.3.1. It is of course supposed that, when comparison between different pieces of equipment is attempted, all other controllable factors such as temperature, reactant pressures, purification of reactants, etc. are held constant to within whatever limits are practicable. 

In order to ensure comparability, it is possible to advance in one of two directions either to use perfectly standard apparatus of a type possessed by all, or to calibrate one s home-made apparatus by use of a standard or reference catalyst available to all. There is much to be said in favor of the former approach, but it implies the use of commercially available equipment, which is unlikely to be cheap and is not yet widely employed. However, experience teaches that there is little difficulty in reproducing measurements concerning the physical properties of catalytic materials (XPS, XRD, TEM, etc.) when, as is usually the case, standard instrumental methods are used. The alternative is to accept that for some time to come many laboratories will continue to use home-made facilities for chemisorption and catalysis, and that there will therefore be a need for a number of standard catalysts that may be tested to ensure the proper functioning of the equipment (and of the operator ). 

The contending scientist, Joseph Louis Proust, was at that time teaching chemistry in Spain. He had made numerous experiments to determine the proportions in which various compounds were formed, and had arrived at the conclusion that Berthollet was entirely mistaken. Proust repeated the experiments of his countryman. He used the purest of chemicals and the most accurate apparatus. He took every precaution to avoid error, and found mistakes in Berthollet s determination. Besides, Berthollet had used substances like glass, alloys, and mixtures of various liquids, all of which were not true compounds. For eight years Proust tried to persuade the scientific world, and especially the followers of Berthollet, that when elements combined to form chemical compounds, the elements united in definite proportions by weight—a theory advanced... 

Each process teaches and provides insight into Nature s operations. Before we can approach this subject however, we need to understand something of the methodology of laboratory alchemy. Many people have the impression that to even begin alchemical work, one must have all manner of expensive chemical apparatus at one s disposal. Not true. You can begin your own alchemical laboratory with common household items just as we did in preparing the "Seven Basics." As one continues the Work, one finds that the materials one needs have a way of showing up when they are needed. 

Alternatively, a saturated aqueous solution of hydrogen sulphide can be used as a reagent. This can most easily be prepared in the bottle B of the apparatus shown in Fig. II. 6. Such a reagent can most conveniently be used in teaching laboratories or classroom demonstrations when studying the reactions of ions. For a quantitative precipitation of sulphides (e.g. for separation of metals) the use of hydrogen sulphide gas is however recommended. 

Solutions. A variety of comments will be given here about the preparation of the required solutions. As noted above, a new sucrose solution must be prepared each day by the student team doing the experiment. The enzyme solution must be prepared and tested in advance, presumably by the teaching staff. Other solutions may be made available to the students or be prepared by them, depending upon the policy of the instmctor. A complete list of all solutions is given in the Apparatus section. 

Modern teaching, research and industrial laboratories are engaged in work that necessitates the use of glass apparatus. The great bulk of this glassware is purchased from laboratory furnishers and, whenever possible, they are the best and most economical sources of supply. 

We use a large range of glass apparatus in teaching, research and industrial laboratories. Only a few common examples are listed in Table 4.2. 

The technical challenges of creating inexpensive and safe demonstration apparatus that make possible evocative observations that effectively teach the principles of materials science falls to scientists themselves. Meeting these challenges is not trivial and it may require innovative apparatus design and component selection. The responsibility of getting the principles and ideas across to students, on the other hand, falls to teachers in consultation with scientists. 

To help solve the problem of fund s shortage such projects be choose which are self-supporting or the projects selected be such that their final products can be sold to partially support the funds. Some such projects are improvising chemistry apparatus, etc. Costly projects should be avoided. As it is not suitable for drill and continuous and systematic teaching, it is not very desirable to use it freely. 

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