Chemical Education Today
Reports from Other Journals
A View of the Science Education Research Literature Visual Aids in Laboratory Manuals Improve Comprehension by William R. Robinson
There are two interesting aspects to the report "Effect In their study Dechsri, Jones, and Heikkinen focus on of a Laboratory Manual Design Incorporating Visual Inforthe effects of drawings. They start with a review of research mation—Processing Aids on Student Learnthat indicates that pictures and drawings ing and Attitudes" by Precharn Dechsri, may be particularly concise ways to commuLoretta Jones, and Henry Heikkinen, pub- …visual images can act as nicate information. These results indicate lished in the Journal of Research in Science conceptual pegs for conthat visual images can act as conceptual pegs Teaching 1997, 34, 891–904. The authors for concepts or for complicated procedures. describe a laboratory manual with changes cepts or for complicated The authors then explore the use of imthat lead to significantly higher student scores procedures. agery in presenting laboratory work. They on measures of laboratory-related achievedeveloped two versions of a laboratory ment and psychomotor skills in addition to manual: an experimental version that promore favorable attitudes toward laboratory activities. They motes visual information processing by incorporating diagrams also provide a useful checklist and rubric for scoring laborathat contain text and that are integrated into the text, and a tory skills. control version with identical activities and structure, but As summarized by Alex Johnstone in his Brasted Lecwithout integrated diagrams. The diagrams were used to ilture (1), studies of the cognitive demands of laboratory work lustrate new equipment, to illustrate construction of apparashow that it places great demands on students' working tus and its correct use, and to indicate procedural sequences. memories. Working memory is the conscious part of our Eighty-three students from four laboratory sections (two minds that holds ideas and facts while we think about them. treatment and two control) of a fundamentals of chemistry We use working memory to process new information gained course were assessed. Students used the manuals for four labofrom our senses and to interpret that information in terms ratory experiments. Achievement pretest and posttest coverof concepts and images recalled from our long-term memory. ing major chemical concepts relevant to these laboratory Thus we use our working memory both for thinking and for activities were used to measure cognitive outcomes. Laboratory short-term storage of new information or recalled informamanipulative skills (methodical working, experimental techtion. As we manipulate information we also hold the results nique, manual dexterity, and orderliness) were measured using of its manipulation in the same space. a checklist and scoring rubric modified from an instrument Working memory has a limited capacity. The maximum published by others. Attitudes toward laboratory were assessed number of different concepts or algorithms that an individual using a survey from the literature. can coordinate at one time ranges from five to seven for adults. This places a tradeoff in our ability to use the space. …visual information aids consisting of pictures If there is too much information to hold, we do not have sufficient space to process the information. If we need to do and diagrams that contain text and that are a lot of processing, we cannot hold much information. Try integrated into the text of laboratory manuals the simple test of capacity described by Johnstone (1); it procan help students perform better in the cognivides persuasive evidence of the existence of the trade-off imposed by our limited working memory. tive, affective, and manipulative domains of The large cognitive load imposed by the text-based inthe laboratory. structions in conventional laboratory manuals laboratory often overloads a students' working memory. Thus students resort to the well-known cookbook approach to laboratory Significant differences were observed in half of the four in order to coordinate the amount of information associated laboratory experiments studied. The differences include inwith the instructions, manipulations, observations, and record terpretation of solubility data, comprehension of reaction keeping that accompany laboratory procedures. rates and equilibrium, favorable attitudes toward laboratory Johnstone and El-Banna (2) suggest that the cognitive experiences as appropriate parts of chemistry learning expedemands associated with laboratory instructions can be reduced riences, favorable attitudes toward the quality of the laboraby using a manual that states clearly what is introductory and tory experiences, and manual dexterity skills and methodical what is central to the experiment, that uses simple and precise working skills. In each case the treatment group achieved at language, that directs students to practice skills before they a higher level than the control group. are used in investigative activities, that lists steps in a proceThe results led the researchers to conclude that visual dure, and that includes drawings of equipment and steps. information aids consisting of pictures and diagrams that
Chemical Education Today
contain text and that are integrated into the text of laboratory manuals can help students perform better in the cognitive, affective, and manipulative domains of the laboratory. Finally, we should note that in the process of designing a research instrument, Dechsri, Jones, and Heikkinen have also given us an instrument that can be used to assess student manipulative skills in the laboratory. This scoring rubric should be useful to instructors who want to supplement their written assessments (quizzes, examinations, or laboratory reports) and use a broader approach to evaluating their students' accomplishments in the laboratory. The rubric could
be used as presented, or could serve as a model to develop a more specific instrument for your situation and expectations. Literature Cited 1. Johnstone, A. H. J. Chem. Educ. 1996, 74, 262–268. 2. Johnstone, A. H.; El-Banna, H. Educ. Chem. 1986, 23, 80–84.
William R. Robinson is in the Department of Chemistry, Purdue University, West Lafayette, IN 47907; email:
[email protected]
