Introduction
The knowledge of the students skills and qualifications from their training in the upper secondary school (grades 10-12; in Danish: Gymnasium) is a useful tool when designing the freshman teaching at the university.
There are two ways of obtaining such information
One is to measure the qualifications at the entrance to the university.
The other is to understand sufficiently detailed the curriculum in school and the syllabi of some important subjects.
As to the first strategy, no tradition for entrance examinations exist in the Danish university system. Further, tradition does not include general procedures for systematic measurements of the qualifications at the entrance to university. At this university the curriculum and tradition does not invite to perform any general, reliable test of the students’ qualifications.
Thus, the desired information would only emerge as teachers’ experience in class. Eventually, a general (but not necessarily precise nor formulated) feeling materialise of what the students know and what they don’t know. Tradition does not include the collection and formulation of such experience in general terms for the benefit of course design. Still, the experience from class is an important source of relevant knowledge for the individual teacher.
The second source of information about the students’ skills and knowledge is the teaching in school.
Here the general picture is quite obscure at first sight. There are several different upper-secondary-school type programs for 16-19 years old students. To cope with this diversity, subjects in the different programs are assigned a "level" and such levels in certain subjects are referred to when admission is given to become a freshman student. With the levels specified, the next step is to understand the significance of these levels. Obviously, the level is obtained by different students with different marks and the individual variation is actually very large. When practical work is considered an even greater variation in skills would be possible, since such skills are not assessed on its own. Still, information is available from the goals and declarations in the syllabus for the subject at the specific level. There are two such descriptions: In the national curriculum regulations1 from the ministry of education the goals for the teaching of the subject (e.g. chemistry) at different levels is declared. Secondly the Guide to the teaching of the subject 2 at a given level specifies and details the curriculum. This material together with the textbooks in use and available published laboratory exercise manuals constitute a source of knowledge of the teaching at a specified level.
In the present study these sources of information about the students’ possible qualifications at the entrance to the university have been studied with special reference to the experimental dimension. The study has been undertaken in order to try to assess the students’ qualifications/skills regarding experimental/practical work. At stage one the study includes chemistry as a central subject of experiments and laboratory exercises.
Goals for chemistry in school
Applicants to the Basic Natural Science Programme (BNSP) at this university have in the upper secondary school been taught at certain levels in science subjects. This teaching include
3 years of mathematics (5, 5, and 5 hours a week, respectively, throughout the year).
2 years of physics (3 and 3 hours a week)
2 years of chemistry (3 and 4 hours a week) and
1 year of biology (3 hours a week)
In short, the levels of these four subjects are named A, B, B, and C, respectively.!
There are no requirements about the marks obtained in these subjects and we get students with good marks as well as students with modest marks.
The chemistry teaching during the first year is compulsory for those in the science branch of the upper secondary school. The 3 hours a week include basic and descriptive chemistry and is organised as a closed course. After the first year the students choose among a number of possibilities if they want to learn more chemistry. Only 40 % of the students choose chemistry for one (or two) more year(s) in a new class with a new teacher.
From the chemistry curriculum1 and the teachers Guide for chemistry 2 it appears that "the practical work (in the second year chemistry teaching) is very important" and some characteristics of the practical work can be abstracted from these texts:
The goals abstracted are:
A to improve the understanding of chemical concepts
B to improve the understanding of experimental methods
C to improve skills in laboratory manipulations
D to improve knowledge of laboratory equipment
E to create attention towards safety issues
F to sharpen the powers of observation
In this formulation the students’ understanding of the important relations between experiment and theory is covered by goal A and B. Firstly experiment and empirical facts give life and meaning to concepts and theory. The understanding of chemical concepts includes an understanding of experimental evidence for the given concept. Secondly, models and concepts give rise to explanations of how and why experiments function. The understanding of experimental methods includes an understanding of models and the concepts thereof.
The next three goals C, D, and E concern the chemical and physical remedies in the laboratory and how to handle them properly, while the goal F is meta-cognitive in nature.
The goals abstracted from the curriculum are qualitative and their impact on teaching has to be specified. This could possibly be done by studying and describing the practical work as it emerges from laboratory exercise manuals, followed by trying to estimate how and to what extent the goals will been reached.
Reference to practical work manuals is given in a report that every teacher has to give to the ministry of education about the actual teaching in each particular class. ! Such reports are not available to the public.
Another relevant source to laboratory exercise manuals are published collections of such manuals, known to be used by a large number of teachers. One problem is, that very many teachers write the manuals themselves or modify existing manuals. Still the published ones are useful sources to the description of the kind and level of practical work in chemistry in school.
Method
In the present survey the experimental/practical work for the B-level in chemistry , i.e. based on two years of study for 3 and 4 hours a week, respectively, is studied through laboratory exercise manuals referred to in 4 different reports to the ministry of education kindly made available by the teachers.!
The 4 classes were different:
One class was an ordinary class in the upper secondary school.
Another class went through a more concentrated course.
Two classes were for students who didn’t choose chemistry for their leaving certificate of the upper secondary school. One of these classes followed chemistry during a one year course on the basis of the language branch of the upper secondary school, and the other took chemistry in a concentrated one month-course on full time on the basis of the C-level in chemistry.
This selection of classes was not the result of a choice, but merely the result of which reports were easily accessible. Since such reports are not available and are destroyed each year in the ministry after use, the access can only be given by the individual teachers themselves. The intention was to extract information from a (little) number of different sources (the reports) from different teachers. The first 4 teachers asked responded with one or two reports and from these the 4 different classes were selected. As it turned out, the 4 classes were not significantly different, when considering the relatively low level of details looked for in the analysis.
In the teachers’ reports reference was given to published collections of laboratory exercise manuals or these were kindly provided as copies of the actual laboratory exercise manuals. All the written manuals were studied and characterised according to the following short version of the goals A-F with the extensions 1-3.
The short version is
A Illustration of concepts
1 are the concepts illustrated central to basic chemistry?
2 how effective is the concept illustrated?
3 to what extent are concepts illustrated in the laboratory exercise?
B Illustration of (experimental) methods (principles)
1 is the method(s) illustrated central to basic chemistry?
2 how effective is the method(s) illustrated?
3 to what extent are methods illustrated in the laboratory exercise?
C Training of laboratory skills (procedures/technique)
1 is the procedure used central to basic chemistry?
2 how effective is the procedure trained?
3 to what extent is the procedure trained through the laboratory exercise?
D Illustration of (the use of) laboratory equipment
1 is the equipment general and often used in chemistry?
2 how effective is the equipment demonstrated?
3 to what extent is equipment involved ?
E Incorporation of safety issues
1 are the safety issues incorporated central to chemistry?
2 how effective are these safety issues discussed ?
3 are the safety issues incorporated sufficient ?
F Need for powers of observation
1 does the work demand careful and detailed observation?
2 is it obvious, that the details are important?
3 are there many important details to cope with?
The characterisation of the experimental work according to the laboratory manuals with respect to the above goals have been put into categories 1 through 3, representing answers to the above questions as
1: yes, indeed
2: more or less
3: no
Results
The concepts found to be illustrated have been listed and grouped. Likewise, the methods and the procedures were identified and put into groups.
The results are summarised below.
Groups of Concepts illustrated found in n out of 10 manuals
Amount and concentration of substance 5
Chemical equilibrium concepts 2
Functional groups 3
Rates of reactions 2
Heat of reactions 1
Groups of methods/principles
The principle of equivalent amounts 3
Electrochemical determination of concentration 1
The principle of Le Chatelier (dynamic equilibrium) 2
Solubility = f(solvent, T, common ions, etc.) 2
Identification of ions, substances or functional groups 2
Changes of some concentration in time (kinetics) 1
Temperature changes caused by reactions 1
Procedures
Measurement of mass (specified precision) 4
Measurement of volume (specified precision) 4
Use of burette (titration) 3
The separation of phases 2
pH-measurements 2
Specific identification reactions 2
Measurement of temperature change 1
Measurement of time 1
From the manuals it was further obvious, that mostly simple laboratory equipment had been necessary during the course, that a pH-meter had been used by everybody, and that a gas chromatograph had been used by or demonstrated to all the students.
Furthermore the safety issues seems not to be predominant.
Finally only in a few cases the need for powers of observation were evident from the manuals.
The general picture emerging from the present study of the laboratory exercise manuals is that the qualitative goals A through D are successfully pursued. The safety issues might be stressed more in the oral instructions in laboratory. Furthermore, only relatively simple demands to powers of observation seems to be needed at this stage.
As suggested from the behaviour of the latest 20 freshmen following their first introductory laboratory course in chemistry at this university, they mastered the above procedures and techniques only when repeated instructions were given. Most of them are able to measure: mass, using a digital balance, time, using a stop watch, temperature, using a thermometer, and volume, using a burette (though not to the limit of precision of the burette). Training is still needed. With the measurement of a volume as an example, the potential of the measuring devise chosen by the students (who didn’t receive instructions) and the accuracy needed for the experiment are not always corresponding very well.
When it comes to the intelligent use of gloves, eye protection, laboratory coat, and other personal protection equipment, the training has also to be continued for some time to become adequate.
Experimental work at university and laboratory manuals.
At the university the objectives are obviously different form those in school. In short the most important role of experimental and practical work at the university is to give the students experience with performing experiments.
Here it is important to distinguish between well planned laboratory exercises and experimental work understood as to go into an experimental investigation of a problem and to plan, perform, and evaluate the relevant experiments properly. In this sense, experimental work is of course part of the processes of scientific enquiry 3
The assessment of experimental work in student projects as it appears in their written reports have been studied 4 using the following list of "Elements of experimental work" in which safety issues have been pointed out, cf. B10 and C 7.
A Objectives
1 Definition of the purpose of the experiments
2 Suggestions for a possible outcome of experiments
3 Experiments suitable for elucidation of the validity of a hypothesis
B Design
1 Use of standard equipment / standard instruments
2 Design of new fittings /accessories to modify the equipment
3 Use of standard procedures /techniques
4 Knowledge of more than one standard procedure /technique
5 Choice between several standard procedures /techniques
6 Knowledge about more than one method / principle
7 Choice between several methods / principles
8 Modification of existing method / principle
9 Development of new method / principle
10 Considerations of safety precautions
C Performance
1 Manual skills demanded by procedure / technique
2 Thoroughness demanded by procedure / technique
3 Time demanded by the complexity of procedure / technique
4 Calibration / standardisation / use of controls / sampling
5 Optimisation of procedure / technique
6 Reproduction of measurements / procedures
7 Safety precautions demanded by procedure / technique
D Evaluation
1 Knowledge of accuracy of method / technique used
2 Statistical analysis of data
3 Use of a mathematical model / fitting of parameters
4 Simulation of the results
5 Adequate presentation of the results / in accord with tradition
6 Comparison of results with existing knowledge
7 Interpretation of results with respect to hypothesis /purpose of the experiments
The laboratory exercise manuals of the 4 classes in the upper secondary school have been analysed using the above listing of elements of experimental work.
It was no matter of surprise that training in experimental work in this sense is not extensive in the upper secondary school. The results are:
A Objectives.
The purpose of the experiment was given in the exercise manual
B Design
Simple standard equipment, simple standard procedures, and basic methods are given in the exercise manual
C Performance
The exercises are short
The procedures are fairly "robust" to the performer and are given in the exercise manual.
Few and fairly simple safety precautions are necessary.
D Evaluation
Instructions to data processing are normally given in the exercise manual. Interpretations are often required and the results have to be compared to table values. These requirements are part of the instructions for the laboratory exercise report.
In view of the objectives and tradition for practical work in the upper secondary school and of the students’ limited experience with practical work it would be difficult to ask the students to set the goals for the practical work and to plan the exercises. In many university programmes this strategy is continued. At this university we invite the students to participate also in the earlier phases of the processes of scientific enquiry 5.