Laboratory instruction experiments

The most commonly applied style of laboratory instruction is the expositoiy one, which is instractor-centred. The learner has only to follow the teacher s instructions or the procedure (from the manual). The outcome is predetermined by the teacher and may also be already known to the learner. The results of the experiments... 

As a conclusion to his preparative course the student should undertake several preparations, for which he has to look up the appropriate methods in scientific journals, instead of finding them worked out in minute detail in a manual of laboratory instruction. In so doing he will learn, with the aid of the directions given above, how to consult the literature, and how to make use of the chemical library most of all, however, these more difficult preparations will serve to test his capacity for laboratory work. When synthesising a compound in several stages it is absolutely essential to test and consolidate each separate stage by means of test-tube experiments before the whole of the substance is risked. Whoever fails to observe this rule will pay dearly for his neglect by loss of material and time. 

The same can be said for student high school laboratory experiences. While we may think our incoming college students have already mastered basic laboratory techniques in high school, that is often not the case. In fact, the National Research Council s (NRC) 2006 investigation of the state of laboratory instruction in high schools in the United States concluded the quality of current laboratory experiences is poor for most students (NRC 2006). In most high school laboratory pro-... 

These experiments are based on methods actually applied or developed for instruction by the two authors during their careers in the radiochemistry laboratory. Each experiment has been tested by students in an academic laboratory setting. The experiments were practice-taught for one semester to a group of graduate chemistry students. The students responses were then used to modify the presentation of the experiments for inclusion in this manual. 

Laboratory Instructions Laboratory instructions should be given in a clear and simple language. It should give a precise but systematic method of performing the experiment. Special emphasis be given on how the record is to be kept and number of observations to be taken. Calculations be clearly explained and precautions to be observed be specifically emphasised. 

Instruction Card In some laboratories instruction cards are used for providing guidance for laboratory work. Each student is given a card containing instructions about the experiment he has to perform. 

Instructions to Pupils When a group comes to laboratory for practical work it should be given a guidance for the experiment to be performed. Such guidance can be given by (i) Laboratory instructions (ii) Laboratory manuals or (Hi) Instruction cards. 

R)esearchers have not comprehensively examined the effects of laboratory instruction on student learning and growth in contrast to other modes of instruction, and there is insufficient data to confirm or reject convincingly many of the statements that have been made about the importance and the effects of laboratory teaching. The research has failed to show simplistic relationships between experiences in the laboratory and student learning (p. 212). 

Fred Leavitt, Executive Director of CCR, and I were witness to the Operation Progress workshop s success. The workshop included experience with computers, lectures on teaching chemistry by Professor Crosby, and extensive hands on chemistry focusing on micro laboratory instruction and a fascinating laboratory built completely around materials that can be purchased in local grocery and hardware stores. This creative laboratory when used by students and teachers should not only promote an interest in chemistry but underline the pervasiveness of chemistry by connecting the laboratory directly to the real world. 

The development of our kinetics experiment feU on the strong shoulders of Paulette Messier, Laboratory Instructor, and adds just one more accomplishment to her unending contributions to the development of the microscale program at Bowdoin College. Fbulette is rapidly closing in on three decades of continuous laboratory instruction at the microscale level, a unique record of experience in microscale anywhere in the world of chemical... 

In the first few years of college, most laboratories in science courses are cookbook laboratories. By this we mean that students read and follow a set of laboratory instructions in order to perform an experiment to collect data. There are many variations on this theme, but beginning students mostly just follow instmc-tions . Some experiments might involve elements of experimental design, but this will be fairly limited... 

The Unit Operations Laboratory at IIT was started in the early 1910s. The Unit Operations outlook was developed by Professor McCormack in the form of senior projects. The laboratory instruction book contributed many of the experiments in the book "Applications of Chemical Engineering," edited by Professor McCormack. Students worked in teams of two or three on projects proposed by instructors or proposed their own experiments. Usually the project involved the building of an equipment item. These equipment items and the experiments were updated from year to year. The laboratory portion of the curriculum required the completion of twenty-four of these home-grown and continuously modified experiments over a span of three semesters. The result was a chemical engineering graduate who could devise a practical way to evaluate the results of industrial processes and to determine the best way to develop these processes. 

The preparation of an ion-selective electrode for salicylate is described. The electrode incorporates an ion-pair of crystal violet and salicylate in a PVC matrix as the ion-selective membrane. Its use for the determination of acetylsalicylic acid in aspirin tablets is described. A similar experiment is described by Creager, S. E. Lawrence, K. D. Tibbets, C. R. in An Easily Constructed Salicylate-Ion-Selective Electrode for Use in the Instructional Laboratory, /. Chem. Educ. 1995, 72, 274-276. 

Paints have their own individual data sheets, prepared by the manufacturer as the result of extensive testing including laboratory tests, field trials and experience in use. These instructions should be followed closely in respect of type of application equipment, operating air pressure, tip size, pot life, curing time at various temperatures, recoating interval, etc. The inspector should have the data sheets available at all times and refer to them. 

The producers need to establish, in general terms or for specific applications of CRMs, dear instructions for the user on how to establish traceability to the stated reference and (implied in the use of CRMs of national metrology organizations) the SI. But the authors experience is that, as the workload in commercial analytical laboratories increases (as analytical laboratories seek to demonstrate their competence and quality to an increasingly discriminating... 

The chemistry laboratory is a place to experiment and learn. You must assume responsibility for your own personal safety and that of people working near you. Accidents are usually caused by carelessness, but you can help prevent them by closely following the instructions printed in this manual and those given to you by your teacher. The following are some safety rules to help guide you in protecting yourself and others from injury in a laboratory. 

First, by indulging his passionate belief in science for the people, he gave students the kind of hands-on education in chemistry that he had wanted as a young man. Before Frankland, students everywhere learned science from books most never even entered a laboratory. Working tirelessly over a period of 15 years, Frankland gradually changed that and dramatically improved the state of science education in Britain. He compiled a list of 109 experiments that students needed to understand firsthand in order to pass his examinations. He wrote a textbook that became a standard for chemistry instruction, in part because it incorporated his ideas on valency and organic structures and his newly developed notation system. 

In tracing a reaction path, likewise, we may find a mineral in the calculation results that is unlikely to form in a real system. Quartz, for example, would be likely to precipitate too slowly to be observed in a laboratory experiment conducted at room temperature. A model can be instructed to seek metastable solutions by not considering (suppressing, in modeling parlance) certain minerals in the calculation, as would be necessary to model such an experiment. 

Paper work that has been generated should be page numbered (with initials) and preserved, ultimately to be bound. The student s laboratory notebook should also summarize the work that has been done. The exact procedures that are used for the preservation of notes on experiments vary from institution to institution. The student should be instructed in the appropriate method what is used at the particular laboratory under consideration. 

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