Richard 1. Harmon
Bridgewater Raritan High School-East Martinsville, N e w Jersey 08836
I
Industrial Laboratory Techniques On the High
At the end of each school year, the seniors at High School-East meet in small groups with faculty members to discuss informally and constructively criticize the academic curriculum. These reactor seminars are an integral part of curriculum revision because many of their suggestions have resulted in new academic courses. The seniors play this valuable role by providing the ideas for new courses of study. One of the more popular offerings of the science department is a course in medical laboratory techniques taught by Department Chairman Joseph P. McGarry. The course is designed primarily for girls interested in careers in medical technology, although many students have continued their education in the field of nursing. Since the medical laboratory techniques curriculum was so successful in meeting the needs of the terminal student, the seniors suggested a similar course in industrial laboratory techniques. Their reasoning was based on the facts that: First, many chemical and industrial businesses are located in the school's vicinity and constitute an employment factor very seldom utilized by the course considerations of area high schools. Therefore, a course in industrial laboratory techniques would meet the employment needs of the industrial community by supplying trained laboratory assistants. By offering specific vocational training, this course would enable students to qualify for jobs BS lab assistants because of better qualifications and diminished "on the job training." Second, the regular chemistry program is limited in scope hecause the majority of stress is on abstract and theoretical concepts, rather than the practical use of chemistry in the laboratory. The college preparatory chemistry course requires a detailed knowledge of mathematics which is beyond the ability of many of the terminal students. Students interested in careers in chemical technology are motivated by doing things rather than developing a theoretical explanation of why things happen. Third, while these vocationally oriented courses in laboratory techniques provide insight into many related professions, they can also motivate the student to continue his education beyond the secondary school level. In response to the seniors' proposal, the science department reacted positively to the idea of a course in industrial laboratory techniques, and set about finding out what a chemical technician does. The work of the chemical technician is practical rather than theoretical and usually directly supports the work of the chemist. It may involve research, design, development, production of chemical products and equip764
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ment; and testing of raw materials, processes, and finished products. The technician may assist in developing new products or processes or in improving existing ones by testing and experimenting. During experimentation, the technician may carry out chemical analysis and measurements with a wide variety of instruments. Experimentation almost always requires computing, tabulating, comparing, and analyzing of results. In testing, he may make chemical and instrumental measurements to determine the nature and quantity of substances present and/or to the characteristics of a substance. In this type of work the technician uses common lahoratory equipment such as beakers, Bunsen burners, analytical balances, centrifuges, or more sophisticated equipment, such as gas chromatographs and spectrophotometers, to name a few (1). However, the quest,ion "What does it take to become a good chemical technician?" still remained unanswered. Our industrial consultants stated that technicians must be able to ~ ~ o skillfully rk and safely with the myriad of laboratory apparatus and instruments available to him. The technician should have a working knowledge of basic chemical properties and vocabulary to aid him in his xork. He should take pride in doing the routine bench xork as \ d l as he possibly can. The technician, being technique-oriented, is an integral part of any research team. It is apparent to the observer that any watered down chemistry course would be an immediate failure because chemistry turns kids off. It was reported in a survey of 10,000 high school juniors and seniors in Union County by Union County Technical Institute, Scotch Plains, New Jersey, that 58% did not take high school chemistry because of no interest; 20y0 said chemistry was "too difficult," even though 70y0 of the students were college bound (2). The solution rested on the development of a course that would educate as well as orientate students to the possibilities of careers in technology. Such a course should simulate industrial conditions in attitude and instrumentation. The only vay to do this is to teach chemistry as a tool, since the technicians are application centered. The students should spend a maximum amount of time in the lahoratory and minimum amount of time in lecture. This is the key to the success of our program. The terminal student is "turned off t,o school" because he encounters failure and frustration in most typical classroom situations. Their minds are attuned to learning through concrete manipulations such as laboratory work. In Piagetian Learning Theory their minds have not developed the re-~ersibilityof thought required for abstractions such
as quantum mechanics or thermodynamics. I n the laboratory setting the terminal student can and does find success because he has the ability to operate the equipment and read simple instructions, without the pressures of an academic classroom. Once the student succeeds, noticeable changes take place in him. He takes pride in his work, often running experiments over to obtain better results. For many, penmanship improves from report to report as the need for clear technical writing is demonstrated. In courses like CHEM Study the unifying principles are developed with lahoratory work providing the basis for this development. Unfortunately, a minimum amount of time is spent in the lab, perhaps once a week for two periods. The CHEM Study experiments are used to illustrate abstract ideas. In industrial lahoratory techniques the majority of the material is learned through laboratory experiments performed by the students, which gives them practice and helps develop skills. Instruction is individualized; when the question is asked, the student is ready to learn. The type of question and the interest of the student indicates the depth of the theory taught. I t is realized that each student has a varied background and different abilities; therefore, each unit consists of a series of mandatory experiments and a series of supplementary experiments for faster students to work ahead of the class at their own pace. The instructor concentrates on the technical aspect rather than the broad general direction expected in the regular chemistry program. Each student is required to prepare written reports that contain the recorded data, interpretations of the data, and conclusions developed from the data as well as appropriate calculations, graphs, and tables. The students are expected to make use of the reference library in preparing their reports. In an attempt to provide a clear perspective of the differences between the approach to chemistry in-
."*
theories of cheniscry. InreroreLafion Of
The . a d d .
che,"i.try i n a technologisel society
struction for the professional and the chemical technician, an Orbital Model of Chemical Education has been devised by the Chemical Technician Curriculum Project of the American Chemical Society (3). The model is displayed in Figure 1. At East, industrial lahoratory techniques is a full year course to he taken as an elective by either juniors or seniors. There are no prerequisites, but it is strongly recommended that a student have completed two years of science, including Introductory Physical Science, and at least one year of math prior to enrolling in the course. The students, male or female, arrange their schedules for the following year early in the spring semester. The guidance department suggests the course to students who express an interest in science or laboratory work. Otherwise the enrollment is filled by word of mouth; there issomedirect recruitment for the program. All students are accepted. The industrial lahoratory techniques program at East is unique in New Jersey because it is run without State or Federal Funding under the vocational education program. While meeting five 45-min periods per week we are still able to include the following topics in the curriculum. Laboratory Ezpe7iments A. Safely and Equipment 1. safety procedures 2. use and care of basic laboratory equipment B. Laboratory Reports 1. write-un oroeedures 4. use of the calculator
C . Physical Measwments
D.
msro properties pri"Eipal1y of incuest to engineers imodus-
E. F. a? data. rnterpreraiim t o assure that data is valid and a p p l i c a b l e t o t e s r r being
performed.
G.
H.
I. 3.
Figure 1.
The "nucleus" of chemistry instruction.
1 . calibration of thermometer 2. meltingpoint 3. boiling paint 4. solubility and solubility curves 5. density 6. fractiond distillation 7. fractional ccystalliaation Basic Chemistqi 1. mole concept 2. determination of a chemicalffomula 3. preparation of molar, molal, and per cent solutions 4. writing and balancing of chemical equations QwlitativeAnalysis 1. analysis of anions and cations--all groups 2. product testing by gas chromatography QuantitativeAnalysis 1. use of the double pan and single pan analytical balances 2. gravimetric sulfur in a soluble sulfate; gravimetric chloride 3. determination of chlorine bv the Mohr tltration 4. proof of the consewstion" of mass through a series of chemical reactions Instlumental Analysis 1. acid-base theory, titration of acid by base, use of the pH meter, titration by pH meter 2. optical analysis using visible range spectrophotometer inchdine s ~ e c t r atransmission l and concentration curves. Beer's law' Chrornatoormhu " ' " 1. paper 2. thin-layer 3. gas-phase 4. electrophoresis Organic SylUhesis 1. preparation and properties of ethyl acetate 2. preparation and properties of acetamide Inoroanic Senthesis
Time is the most limiting factor. I t means that Volume 49, Number I I , November 1972
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the experiments must he run in one class period, or must provide convenient stopping points in the procedures. To provide the maximum amount of time in the laboratory, lectures are limited to one period a week wherever possible. This period is on Monday and includes such items' as: theory and operation of the instruments and equipment to he used; the significance and applications of analysis performed; details of analytical procedures and calculations; interpretations of data; etc. The students are allowed to proceed at their own pace as long as they successfully complete the required experiments for the marking period. The general urocedure is to clive the students a known determina Lion so that they can perfect their techniques and ask questions about the analysis. They next do the experiments using unknowns on which they receive grades. A 1-27, span in accuracy is considered acceptable. The initial experiments prove to he quite enlightening for both instructor and student. They are run very hastily and with little precision. However, the student has the option to run any experiment over if he wishes to improve the outcome of the experiment and receive a better grade. Thus as time passes, the results improve to a satisfactory level. ' The experiments previously listed are designed to acquaint the student with basic instrumentation safety and to foster proper lab techniques. There are no specific industrial laboratory procedures employed as such, however, the core experiments are similar to determinations performed and techniques employed . . in industry. The following procedure is included as an example of a t,ypical course experiment and follow up. It is the classes' favorite, and timelv in anv discussion of air pollution.
i-octane 2,2,4-trimethyl pentane, (C8H18)has been assigned the value 100. The octane number is based on the heptme i-octane mixture. TEL is the most widely used additive t o increase the octane rating. The current concern about pollution of our atmosphere has had a tremendous impact on the petroleum industry and the gasoline it produces far automobiles. Up until ahout 1970, only one high octane (loo+) gasoline was available which did not contain l e d compounds as anti-knock additives. Now, the pressure to decrease or eliminate the lead pollution of our air has resulted in many new unleaded or lowleaded gasolines. If lead compounds are not used, or artre used in small amounts, other chemicals are added t o improve octane ratings. One of the best and most popular is toluene, which has an octane rating of
Figure 2.
Correlation of Octane Rating and Composition of Gasolines (4) Purpose
To examine the composition of gasoline using gas chromatography. Introduction
The cause of engine knock (ping) is a complicrtted phenomenon. Compression ratio, preignition of fuel, flame propagation, and basic design chaacteristics mitigate t o disrupt piston travel and speed and thus eause heavy knocking noise. After a long series of tests, beginning in the early 1920'9, it was determined that knocking was due primarily t o the chemistry of the fuel, and a great amount of research in the field of fuel additives was carried out. In the early 1920's the discovery of a, compound, tetraethyl lead (TEL), as s n effective anti-knock formula was made. Sales of gasoline containing T E L had hardly begun when they were halted in May 1925; the reason was forty-five cases of lead poisoning s t a pilot plant. Due t o extreme toxicity of TEL the amount used in gasoline was limited t o 3 ml/gal. Although the use of TEL greatly increases the octane rating of gasoline, ils use causes the accumulation of lead deposits on the engine. This problem was solved by adding ethylene hromide and ethylene chloride t o the TEL. In the presence of these halogen compounds, combustion converts TEL t o lead bromide and lead chloride. These compoonds are volatile enough a t engine temperature to escape complet,ely from the cylinders with the exhaust gases. Octane ratings of gasolines are measured using a procedure specified by t,he American Society of Testing and Materials on a special one-cylinder engine. To establish the octane scale, n-heptane (C,Hla) has been assigned an octane number of 0, and
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Chromatogrom of lemdod gosoline.
120. I t is a hydrobarbon which; like other hydrocarbons, burns to give primarily carbon dioxide and water. In this experiment yo,! will examine several gasolines, leaded and unleaded, high and low octane fuels, t o see if your can detect the difference in chemical composition in the fuels. Over 150 different chemicals have been identified in gasoline and 6ur simple experiment will not come dose to skpatatiting and identifying them $1. In fact, it will be di;ficult to pick out the lead compound. Hence, we will focus our attention on the relative petterns of peaks, and especially on toluene. The greater the toluene area the lower the TEL content.
Instrument Settings 4 f t X I/, in. DNP oven temperature: 130'C column: chart speed: 1 in./min chart span: 10 mV 60 ml/min attenuator: X 1 flow rate: current: 260 mA sample size: 1 J Procedure 1) inject s. 1 J sample of leaded gasoline 2) inject a. 1 pl sample of unleaded or lowleaded gasoline 3) inject a 0.5 PI sample of toluene 4) inject a 0.5 pl sample of hexane 5) inject a 0.5 pl sample of heptane
Calculations 1) measure in cm the adjusted retention times of pure toluene, hexme, heptane 2) using the adjusted retention times, identify these components in the gasoline ssmples 3) calculate the areas t o the toluene peaks in both gasoline stlmples 4) compere the toluene content of the gasoline samples, which area is the greatest, by how many times
Chrornotograms
See Figures 2 4 .
toluene hexane heptane
Actual data
retention time adjusted 7.9 + 0 . 1 cm 1.7 & 0 . 1 cm 3 . 2 & 0 . 1 cm
area leaded 2 . 6 cmz
area unleaded 4 . 0 cma
The toluene content of unleaded is 1.5 times ss great as in ieaded gasoline.
Conclusion
When the TEL content of gasoline decreases a proportional increase in toluene content can he seen. Therefore. the toluene peak can be used as an indicator of the relative concentrations of TEL by using glc.
The chemical industry is the fastest growing ihdustry in the United States. This industry accounts for 7.595, of all manufacturing shipments, 5% of the gross national product, and 2095, of all industry-financed research and development. It touches directly or indirectly on every phase of our life. Many of the basic things of modern living-plastics, drugs, medicines, paints, etc., could not exist without the chemical industry. Even more startling is the prediction that by 1975 more than three-quarters of the industry's business will be in products not yet developed (5). The need for trained chemical technicians and laboratory assistants is ever increasing. In 1970, 6Q1500 people were employed as technicians. Hoaever, a substantial proportion of the personnel so employed at this time have not met the minimum educational requirement of an associates degree, or equivalent. Also a large percentage of those employed as technicians are dropouts from four-year institutions. By 1980, 214,000 trained technicians will be required by industry. At the present rate of training-less than 1000 new graduates per year-there will not bc enough trained people to meet the demand (6). With the demand for technicians far outnumbering the supply, it is the responsibility of secondary schools to respond to industry's need by providing weight into technical careers, through vocational courses, like industrial laboratory techniques. These courses should not be standard chemistry courses but should be oriented to the educational demands of a technically trained person. The industrial laboratory techniques course at Bridgewater-Raritan High School-East is a beginning. Educators have been aided by instrument manufacturers who have now placed on the educational market low-priced and technically sound instruments such as: Sargent-Welch's pH meters, Bausch and Lomb's Colorimeter and Cow-Mac's Model 69-050 Student Gas Chromatograph. These instruments help to provide low cost learning laboratories that approximate industrial conditions. I n conclusion, the burden of helping industry meet its commitments to a groaing tec'hnological society has finally come to rest on the secondary school. We as science educators must take this opportunity to revise and strengthen our curricula. By doing so not only industry, but also the student mill profit. Thb Student, whose occupational prospects were once limited, can now enter the technological age and function as an intregal part of our technological society. Literature Cited Technician," Chronioai Guidance Puhiiostions Ino.,Maravia, N . Y., 1966. (2) Union (Nes Jersey) Leadei. "Chemistry Turnr Kids OK," July, 1971. p.23. (3) "Chemistry in the T w o Year College." Committee on Chemistry in the Two Yea: College. Division of Chemieal EduOation, ACS. p. 52. (4) Cow-Mae Laboratory Mamlal, Model 69-050 Student Gas Chrornhtograph, GOW-MAC INST Co.. Madison, N.J. (5) - A ~~t~~~ as a chemied ~ ~ ~ h ~ ~i ~ i ~~ ~ . ~ciiemists . , ~ AS- ~ aooiation. (8) Enuiionmcnlal Science and Technology, April. 1971, p. 318. (1) Occupational Brief-"Chemical
. 16 . Figure 4.
Reference ehromdogrm of heptone, hoxano, and toluene.
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