Teaching and Learning Forum 97 [ Contents ]

Learning in the laboratory

Mauro Mocerino
School of Applied Chemistry
Curtin University of Technology

Introduction

Laboratory classes are very complicated environments with a mixture of practical activities and theory coupled with a considerable amount of distracting information which often masks the important concepts of the class. To alleviate some of this complexity laboratory manuals are usually written with clear step by step instructions. However, this allows students to successfully complete experiments simply by blindly following the instructions, without any attempt to understand the processes involved. Some students are so concerned with "getting the right answer" that they often do not recognise what they are supposed to be learning from the laboratory. Furthermore, many students seem to regard laboratory work as something which must be endured and enter the laboratory class with the aim of carrying out the exercise as quickly as possible. It is rare that a student enters the laboratory with the attitude that the three hour session is an opportunity to gather as much information as possible on the concepts/techniques involved.

Laboratory tests

Students were given a short test which examined a few of the key concepts of the experiment at the completion of each experiment. The whole concept of using laboratory tests is based on work done by Peter Simpson (1993). The laboratory tests were developed because it was felt that students did not take advantage of the learning opportunities available in laboratory classes. These tests were introduced primarily to encourage (stimulate/scare.....) students to think more deeply about what they were doing in the experiment. Students were also encouraged to discuss the experiment and any questions they have with their peers and the laboratory supervisor during the class. During the test, students could refer to their laboratory manual and notebook; the use of the latter encouraged good recording of observations and results. Each test consisted of about five short answer questions and took approximately fifteen minutes to complete, although there was no time limit.

A well constructed laboratory test can require observations, details of technique, explanations, inferences, generalisations, predictions, calculations and anything else that is pertinent. The questions in the test should require the student to demonstrate an understanding of the experiment. For example, consider an experiment in which students were asked to add five millilitres of dilute sulfuric acid to a reaction flask. To encourage the students to think about the function of the acid, one could ask a question relating to the degree of accuracy required in measuring the volume of acid, or whether another acid could be used instead. If the questions are trivial, then there is no stimulus for the student to perform at a higher level. Students are still required to prepare and submit laboratory reports but they are not examined in detail. Instead an aspect of the report is examined and the results of the experiment are usually included as part of the laboratory test assessment.

The intended outcomes of using laboratory tests included:

Evaluation

The students were surveyed at the end of a semester of being assessed by laboratory tests to determine their opinions of the process. The survey was in two parts, the first required students to give a numerical rating to twelve questions on a scale of one to nine (one-strongly disagree; five-neutral and nine-strongly agree) and the second required responses to some open ended questions. The questions for Part A of the survey and the average score (a total of 112 students were involved) are given in Table 1, below.

Table 1: Part A of the student evaluation of laboratory tests with average scores.

No.QuestionAverage score
1.You found the lab tests stimulating and challenging.5.7
2.Your interest in the labs has increased as a consequence of the lab tests.4.5
3.The lab tests have helped you learn and understand the concepts of the lab.6.2
4.The lab tests emphasised the key concepts of the experiment.6.9
5.The lab tests stimulated you to discuss your results with your colleagues.6.5
6.The lab tests stimulated you to share your ideas and knowledge.6.2
7.The lab tests stimulated you to ask questions during the lab.6.5
8.The lab tests provided valuable feedback.5.9
9.The lab tests are a fair and appropriate method of assessment.5.6
10.The lab tests did not add significantly to the stress of the lab class.4.8
11.The lab tests stimulated you to think more deeply about the experiment.6.3
12.The lab tests helped to link the concepts covered in the lab with lecture/tutorial material.5.9

The response to question two was of serious concern. The low score was probably due to the added stress caused by having the tests at the end of the laboratory class (see also question ten). Many students indicated (in Part B) that they had to rush the experiment and had no time to digest the information gained during the experiment. Many of these students also indicated that they would have preferred to do the test in the following laboratory class. The level of discussion relating to the experiment in the classes with laboratory tests seemed to be higher than in those without the tests. Furthermore, students in classes which had weekly laboratory tests asked more questions of the laboratory supervisor and a greater proportion were directed towards an understanding of the concepts involved. These observations are in agreement with the student responses to questions 5-7.

The open ended questions in Part B gave a clearer indication of some of the opinions/concerns of the students. Approximately 60% of the survey forms have been analysed to date and some of the more common responses are listed in Table 2 (the number of responses is given in brackets). The number of responses may exceed the number of survey forms as many students gave more than one point in response to some questions. It should also be noted that a response of 'no' to questions 13-15 is not necessarily a negative result as many of these students already perform at a high level (the students involved in this trial are among our top students).

In the main the comments were very favourable, with the most obvious criticism relating to the added stress caused by the tests. It is believed that by doing the tests in the following laboratory class, prior to commencing the new experiment, much of this stress will be relieved. Students will then have the week to go through their results and properly digest their data. Some students who severely criticised the laboratory tests indicated in an interview that they would be happy with the tests if they were administered the following week. Another criticism stems from the apparent lack of understanding by the students of the objectives of the laboratory tests. Many saw them as assessment tools for theory which was covered in lectures and did not recognise that the questions were directly related to the laboratory. This inability to associate laboratory experience with theory has also been observed by others (Stensvold and Wilson, 1992; Nakhleh, 1994). Some thought that the laboratory work carried out was not adequately rewarded, especially given their perception that the test were theory based. A pleasing aspect of the comments was the large number of times students indicated that the tests stimulated them to modify their behaviour for the better. These improvements included better preparation, more concentration, better attitude, deeper thought and understanding.

Conclusion

It is believed that the laboratory test have been useful in stimulating students to better performances in laboratory classes but improvements are required to enhance these benefits. The most obvious is to give the test on the following week, thus giving students a week to digest their results. Although, this has the disadvantage that students do not get feedback until two weeks after the experiment, the advantages gained in the reduction in stress should greatly outweigh this. Another modification is to better communicate the objectives of the laboratory tests; a brief description at the beginning of the semester is insufficient.

Table 2: Part B of the student evaluation of laboratory tests with some of the common responses.

No.QuestionResponses
13.Has your preparation for the laboratory classes changed since the introduction of the laboratory tests? If so, what do you do differently?no (43)
yes-read background/lab notes (10)
yes-prepare better (7)
14.Has your behaviour changed in the lab as a consequence of the lab tests? If so, how?no (33)
no-still do my best (1)
yes-increased concentration (9)
yes-more rushed/stressed (8)
yes-ask more questions (8)
yes-more careful (8)
15.Has your attitude to lab classes changed as a consequence of the lab tests? If so, how?no (26)
no-still do my best (1)
yes-don't enjoy labs/more stressed (12)
yes-take labs more seriously (8)
yes-increased attention (7)
yes-increased interest (2)
16.Do you feel that the lab tests have helped you learn the concepts covered in the laboratory? If so, how have they helped?no (12)
yes (9)
yes-summarise lab (17)
yes-stimulates thinking/learning (13)
yes-good feedback/revision (7)
yes-links lab and theory (6)
17.Do you feel that the lab tests have helped you learn the concepts covered in lectures? If so, which areas have benefited?no (19)
yes (14)
yes-organic chem. (13)
yes-all sections (10)
yes-phys. chem. (8)
18.Do you prefer the use of lab tests as a form of assessment? If so, why? If not, how would you like to be assessed?no (6)
yes (23)
no-assess reports (10)
no-not fair (6)
no-assess techniques not theory (5)
yes-fair not based on results only (8)
yes-good summary/feedback (5)
yes-but on following week (4)
yes-easier (3)
yes-tests understanding (2)
19.Would you like to see the use of lab tests more widely in your course? If so, in which areas?no (41)
no-not applicable in other areas (8)
yes-subjects with labs (5)
yes-others (5)
20.What do you consider the main advantage(s) of using lab tests?good summary (16)
stimulates deeper understanding (11)
good feedback/revision (9)
stimulates thought (8)
clarifies concepts (5)
tests understanding (4)
others (4)
none (5)
21.What do you consider the main disadvantage(s) of using lab tests?lack of time (26)
stress (15)
questions too hard (8)
have to rush (6)
not based on lab work (3)
collaboration during test (3)
others (7)

Acknowledgments

I would like to thank Dr Peter Simpson for his many helpful discussions and Drs Roland DeMarco and Dierdre Pearce for their enthusiasm in implementing this program in their laboratory classes.

References

Nakhleh, M. B. (1994). Chemical education research in the laboratory environment: How can research uncover what students are learning? Journal of Chemical Education, 71, 201-205.

Simpson, P. (1993). A new approach to teaching and assessing practical work in upper school chemistry. Perth: Science Teachers' Association of Western Australia.

Stensvold, M. and Wilson, J. T. (1992). Using concept maps as a tool to apply chemistry concepts to laboratory activities. Journal of Chemical Education, 69, 230-232.

Please cite as: Mocerino, M. (1997). Learning in the laboratory. In Pospisil, R. and Willcoxson, L. (Eds), Learning Through Teaching, p222-226. Proceedings of the 6th Annual Teaching Learning Forum, Murdoch University, February 1997. Perth: Murdoch University. http://lsn.curtin.edu.au/tlf/tlf1997/mocerino1.html


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