VOL.2, No. 3
LABORAT~RY INSTRUCTI~N IN ORGANICCHEMISTRY
207
A SYSTEM OF LABORATORY INSTRUCTION IN ORGANIC CHEMISTRY J. W. How~no, STATE UNIVERSITY, MISSOULA, MONTANA The system described in this paper was first introduced to the author while he was an assistant to Dr. C. G. Derick a t the University of Illinois. Dr. Derick had i t worked out in a highly perfected form even to the recording of the results. This account of it is given from the viewpoint of nine years' satisfactory use as a teacher. It can perhaps, best be described by reproducing a copy of the instruction sheet given the student, as follows: The laboratory work in this course is divided into four parts. First. The student is required to read over the directions and necessary literature in connection with each preparation and bring to the instructor, before the preparation is started, a written report, called a "preliminary report," containing the following data: Date
Title
Name of Student
1 A list of the physical properties of all substances used and prepared in the experiment 2 The main reaction for the preparation (the equation being given in steps where possible) 3 The chief side reaction which might take place 4 Best experimental conditions, i. c., mass relations; temperature control; method of mixing ingredients; precautions, etc. 5 Reasons for and reactions (if any) of method of purification used 6 Equations for two other general methods of preparing the same compound.
The responsibility for having this report approved before starting the experiment is placed upon the student. Second. The apparatus "set up" must be checked before proceeding with the experiment. Third. The finished product must be turned in suitably labelled and in acceptable form, in order to receive complete credit. Fourth. A "Final Report" containing this data: Date
Title
Name of Student
1 Brief description of experiment 2 Report of yield and calculation of % yield 3 Two typical reactions of the compound prepared.
Two methods of recording the work in note books have been tried by the author. In one a bound note book was used, writing the "preliminary report" on the left hand sheet and the "final report" on the opposite right hand sheet. In the other loose leaf paper was used. The latter is preferred in that the instructor can retain the reports and hence stop the circulation of approved reports among the students.
U)8
JOURNAL OP CHBMIW E~UCATION
MARCE,1925
Obviously the system best adapts itself to a course where the main experimental work is preparations. If these preparations are so selected that each represents a class of compounds the written work gives a very good review of that class. The preliminary report prevents one of the most common faults of laboratory instruction, allowing the student to grind through a lot of work and t h a go to the literature to find out what i t was all about. The checking of the "set up" not only insures the actual doing of the work on the part of the student, but is a wonderful preventative against careless manipulation. Time is allowed in the laboratory period for the writing of the reports. While this cuts down somewhat the number of preparations that can be done, we believe it is a good sacrifice of quantity for quality. The student is encouraged to get several preliminary reports ahead and so plan his work that the loss is not as much as might be expected. We require that no student be back with more than three finals a t any one time, and thus keep the notes "hot." If the class is small (eight or ten students) the instructor can give iudividual oral quizzes on both reports. With a class of fifteen this can be done with the preliminary report only. A class of twenty to twenty-four can be handled by simply checking the reports and omitting oral quizzes. The ditferent rates a t which students work has been found to be such that there need be very little loss of time on the part of the student waiting his turn to have his report approved. We will have to admit that this system "works" the instructor as well as the student, but the satisfaction in the results well repays the additional effort.
