Research in Science Education, 1993, 23, 259-265

CONCEPTIONS OF WATER-RELATED PHENOMENA

R. A. Schibeci, A. Fetherstonhaugh & S. Griffin Murdoch University Edith Cowan University Murdoch University

ABSTRACT Water is an important resource. Surprisingly, research into students' conceptions of water has been confined largely to studies of change of state. This paper reports the results of interviews about underground water, water pollution, the water cycle, and change of state). There were 45 students interviewed about these phenomena: all were in Year 9 or Year 10 in Western Australia from three schools, two country, one metropolitan. In addition, 715 students in Years 9 and 10 in five government schools, three metropolitan and two country, completed a teacher-made, water topic test. Students appear to have a good understanding of some water-related phenomena, such as the water cycle, but have conceptions about other phenomena, such as the water table, which are not in accord with scientific views. As others have reported, interviews reveal that student~ often use scientific language without understanding.

INTRODUCTION As in many other parts of the world, water in Australia is not an unlimited resource. In the Perth Basin of Western Australia, a rapidly growing population will continue to compete for this finite resource. Important decisions concerning the management and use of water resources can best be made in cooperation with the community. The nature of such cooperation may well be determined by the level of understanding about local water resources.

There are several different interest groups that have specific concerns with water and water resources. These groups include state-wide non-government agencies such as the Conservation Council of Western Australia; specific water interest groups such as the Wetlands Preservation Society; and, the Australian Conservation Foundation. State government bodies which have a direct interest in this area are the Water Authority of Western Australia, the Waterways Commission and the Environmental Protection Authority. All of these groups receive inquiries from the community members about water. The Water Authority, being the principal supplier of water, provides a lot of information on water issues to the public and has become increasingly aware of its accountability to the public. Nancarrow and Syme (1989) suggest that there has been increasing interest within major water authorities in the level of public understanding of water management issues.

Past research findings (Zube, Vining, Law & Bechtel, 1985; Happs, 1986) suggest that general levels of community scientific understanding concerning environmental problems are likely to be low. Environmental decision-making, not surprisingly, tends to be mediated by the pre-conceptions held by individuals (Ghiselin, 1982); this is consistent with current knowledge about information processing as described in the "constructNist" literature 0Nittrock, 1981; Strike & Posner, 1984).

The materials available and currently used in schools regarding water are often general in nature, with limited attention being paid to the particular problems of a local community. In addition, available materials may be unsuccessful in bringing about a change from general community conceptions to scientifically acceptable conceptions.

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A joint project between the CSIRO Division of Water Resources and Murdoch University was initiated to investigate conceptions of water and water-related phenomena among a sample of high school students. Two research questions guided our work, one substantive, the other methodological:

* What are some common student conceptions about water-related phenomena such as change of state, water pollution, the water cycle and underground water?.

* What are some fruitful probes of student conceptions of water-related phenomena, particularly suitable for classroom teachers?

PREVIOUS STUDIES Probes of student conceptions Carr (1991) noted the emphasis over the past decade on qualitative methods which probe what students actually think, as opposed to testing students on aspects of a concept that they are presumed to know about. Among these methods is the interview, which has been used in research on personal construction for many years. Piaget also used a clinical interview technique with children to understand their ideas on several areas of physical science, including some properties of water (Piaget, 1929). More recent applications of interview methods, including Interview-about-Instances and Interview-about-Events procedures, according to Cart (1991), provide for a =focused conversation about external stimuli, and concentration on them removes the oppression of eyeball-to-eyeball confrontation. The focus materials are deliberately familiar and 'real world' so that responses are triggered from contexts outside of, as well as within, the school, laboratory or classroom." (p. 17) Both procedures have been used to explore frameworks held by science students around the world.

The amount of time taken to conduct each interview is a major drawback of the method, as it is difficult to establish reliability and validity of data unless the process has been trialed and modified accordingly. Hill and Wheeler (1991) used the Interview-about-Instances procedure to elicit students' ideas on scientists, science and technology. They found that "reliability was influenced both by the number of illustrations used and in their order of presentation" (p. 127). As teachers generally do not have the time for extended interviews, we explored the use of a questionnaire on water-related phenomena in addition to interviews with a sample of 45 students. The statements in this questionnaire were derived from the literature, reviewed briefly below, and from student interview transcripts.

S.t.udent conceptions of chan.qe of state In reviewing studies that address students' perceptions of water, it is important to note that few have been completed in Australia, even though Australia has major water concerns. Studies on water-related phenomena have focussed on student conceptions about changes in state (Bar, 1989; Osborne & Cosgrove, 1983; Russell, Harlen & Watt, 1989; Mangan, 1992). Few studies have involved children's understanding of the complete water cycle or underground water. Bar (1989) reported that children's understanding of certain water-related concepts was a function of age. Her conclusions were based on interviews with Israeli children aged 5 -15 years. For example, children's conceptions of evaporation could be categorised into one of four age-related views, as follows: (1) the water disappears (age 5-6); (2) the water penetrates solid objects (7-8); (3) the water evaporates into some =container" (9-10); or, (4) the water evaporates, it is scattered in the air (age 10-11).

Russell et al. (1989) investigated the views of a sample of UK students aged 5 to 11. They also reported an age-related difference in students' conceptions of evaporation in two of the three experiments that the children in their sample completed. In one of the experiments, the students had to explain the evaporation of water from a tank. The majority of the youngest age group (aged 5-7) did not mention conservation of the water, nor change of phase, but

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instead focused on the water that was left in the tank. In the two older age groups (8-9 and 10-11) the most common response to the waters disappearance from the fish tank was that the water moved in "unchanged form" to a remote site; this view increased with the older (10- 11) sample. Osborne and Cosgrove (1983) used the Interview-about-Events method to gain insights into the conceptions held by chi[dren aged between 8 and 17 years on boiling, evaporation, condensation and melting. They found that students appear to understand these phenomena and to be using the correct words to explain them, but when asked what specific scientific words mean, the same students had "no sound scientific concepts underpinning these labels" (p. 836). In some cases, non-scientific ideas may actually increase with age as students learn more 'science words' and apply them incorrectly. For example, some of the older students in their sample thought that bubbles in boiling water were made of elemental oxygen and hydrogen.

Driver, Guesne and Tiberghien (1985) support this limited use of scientific language: they found that "pupils added the words 'conductor and 'insulator to their vocabulary without substantially changing their ideas about heat transfer" (p. 198). It has been suggested that one reason for the confusion of scientific terms and the actual process that they describe is that so many words used in science are the same words that are used in everyday language, only that they have a slightly different meaning (Gunstone, Gray & Searle, 1992).

Ideas at odds with accepted science ideas may arise from the way that children tend to base their reasoning on things that they can observe (Driver et al., 1985). Similarly, Russell et al. (1989) suggest that "children are susceptible to focussing on very particular attributes of any given stimulus material" (p. 575): this could have important implications in the way that stimulus materials are chosen.

Finally, there is evidence which suggests that even after formal science learning, the conceptions that the students hold before instruction continue to be the conceptions that they use to interpret phenomena (Gunstone et al., 1992).

METHOD

The first approach in eliclting student conceptions of water and water-related phenomena was the Interview-about-Instances technique, which has been widely used in research on students' views on a range of science phenomena. In this study, students were shown a series of eight line diagrams with captions relating to water phenomena. A question, which was the picture's caption, was read. Each question was designed to elicit the student's knowledge in a specific area, such as ground water, rain, lakes or domestic water use. For example, one diagram showed a line drawing of a lake in the middle of winter with water in it, and the same lake in the middle of summer with no water in it. Below the diagrams were two questions: Why is the water no longer there in summer?. Where has it gone?

The second approach was a Water Questionnaire, which comprised 34 statements about water. The statements, which were derived from the initial set of student interviews, as well as the limited previous research in this area, were grouped into clusters of four or five statements that related to a theme. Respondents were required to rate each statement on a scale from 1 to 5:1 corresponded to '1 am sure this is right'; 3 corresponded to '1 don't know if this is right or wrong'; 5 corresponded to '1 am sure this is wrong'.

The third approach was to administer a teacher-made test on water to test students' understanding of school science, as teachers rely on such data from their own testing programmes. There were twenty questions taken from end-of-topic tests on water from a number of schools. (These end-of-topic tests are administered to students (usually in Year 9)

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who have completed the elective science unit, Water: The essential fluid at these schools.) To this set of twenty questions, we added three multiple choice items from Osborne and Cosgrove (1983). These three questions were based on student responses to interviews, and probed student understanding of evaporation phenomena. They allowed us to make direct comparisons with New Zealand data.

SAMPLES

Students from five different schools were involved in the study. Each school was approached (and agreed) to take part in the study. The secondary student population at each school was, respectively:. Deionised, 1021; Aqua, 977; Evian, 402; Distilled, 259; and, Perrier, 50 students. Two were schools in the metropolitan area of Perth, Western Australia (Evian and Deionised); the remaining three schools were outside the metropolitan area (Aqua, Perrier and Distilled). All five were government schools.

Students from Years 9 and 10 were chosen for the study. In all, 45 students were interviewed: 18 Year 9 students and 27 Year 10 students (from Aqua, Perrier and Deionised schools). The multiple choice test was completed by 715 students, and the Water Questionnaire 660 students.

RESULTS Interview Data The interview transcripts were analysed using a conceptual inventory method, described by Griffiths and Preston (1992). These authors used the inventory to establish students misconceptions; however, this method was modified to determine conceptions that the students held, regardless of whether they where "scientifically correct" or not.

The most common conceptual categories were then established and the responses from each interview question were grouped where possible so that the students conceptions could be viewed against the original instance in the interview. A descriptive summary of the conceptions that emerged and the frequency with which they appeared was compiled. After the initial analysis, it was found that there were few significant differences in the frequency of conceptions held by students in the three schools, but there were some differences between Year 9 and Year 10 students.

Evaporation. Several question in the interview were designed to probe student's knowledge of evaporation. Most students said that water from a puddle might evaporate, as would rain that had fallen. Most suggested that water from a lake or puddle would evaporate and go up to form clouds. These results are consistent with the findings of Bar (1989), who reported that the oldest children in her sample (age 10-11 years) believed that water from a tank evaporated and scattered in the air. These students were aware that the water had changed form, from a liquid to a gas, as did the students in the Western Australian sample, although these students are several years older than the students in Bar's sample. The older students in the study reported by Russell et al. (1989) were of a similar age group to those in Bar's study, but they found that the students believed the evaporated water had moved in "unchanged form"; that is, the water had not changed phase to change location. However, the students from both of these groups are much younger than the students used in the Western Australian sample.

Water Cycle. The majority of students in the sample had some knowledge of the water cycle. While most of the answers given were scientifically correct, students often appeared to use the scientific terms without understanding. Answers to questions about boiling water and evaporation of water from both a puddle and a lake, showed that students had scientifically correct conceptions about the process of evaporation. This view was further consolidated by

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the responses that the students gave to the questions about the clouds and rain. The students in the sample most commonly said that rain was made of water droplets, water vapour or evaporated water, and that before the water had formed clouds it was water on the ground or in the atmosphere. Almost all of the students knew that the rain that had fallen would end up being evaporated at some stage, therefore completing the cycle.

Underground Water. Students appear to be confused about underground water. For example, a common answer on a question on what would happen to water in a puddle was that the water would quickly soak down to the water table. Students knew that bore water came from the water table, but there were differences of opinion as to how the water would get out of the water table. The majority of Year 10 students said that the bore water was pumped to the surface. Year 9 students either did not respond or said that natural pressure in the ground forced the water to the surface. Another question probing this area concerned a leaking petrol tanker. Students suggested that the petrol would either evaporate or soak into the ground, and that the petrol that does sink into the ground could affect the water table.

Boiling. The question on water boiling in a saucepan was, at least in part, well answered by most students. The majority of students suggested that the water would evaporate and become water vapour or steam, which would rise to the ceiling and then condense and form water droplets. Students may have been able to answer this question well because it is readily observable at home (supporting the suggestion of Driver et al. (1985), and some students may have completed a similar task in school science. Students, however, appear confused about the composition of bubbles in boiling water. Although the most common response was air, a variety of other responses were also given such as [elemental] oxygen, steam and [elemental] oxygen and hydrogen.

Pollution of Water. Two questions were designed to investigate students' knowledge of water pollution issues. The first was a question about algal growth in summer. The most common conceptions that the students held about algae were that algae grow more in summer than winter and that algae needs "run-off' to bloom. Some students were not clear about what algae actually are: among the responses were pollution, seaweed, bacteria or chemicals. A few students thought that the algae would grow more in winter because of the increase in water supply. The other question that addressed water pollution was the leaking petrol tanker. As stated previously, while some of the students knew that the petrol could soak down to the water table, few students saw this as posing any real threat to the water supply, and those that did mention water supply said that this water would only be used for gardens.

Water Test Scores on the twenty questions of the water topic test ranged from 0 to 19; the mean was 11.0, with a standard deviation of 3.6. Just over one quarter (27 per cent) of the sample scored 9 or less. The internal consistency of the test (coefficient alpha) was 0.67. Discrimination indices for twelve of the twenty items were 0.4 or greater, with five of those twelve items 0.5 or greater.

Water: The essential fluid is an elective science unit taken by some students in Year 9 or, less commonly, Year 10. Interestingly, the mean score for the 24 per cent of students who had studied this unit was 11.8 compared with a mean of 11.0 for those who had not studied the unit. This difference was not statistically significant. Similarly, there was no statistically significant difference between the mean score for females (48 per cent of the sample) and males. It may be that students who had done the unit had forgotten some of the material they had learned that was specific to the unit. Some ideas (such as change of state) are reinforced in other units, which provides an opportunity for revision.

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Chan.qe of state Three multiple choice questions were based on earlier work by Osborne and Cosgrove (1983). Of our sample, 41 per cent incorrectly thought that the bubbles in the boiling water question were made of elemental oxygen or hydrogen. Just over half (52 per cent) of the students answered the question on evaporation correctly:, water would become "bits of water in the air". However, 33 per cent of the students said that the water would "change into oxygen and hydrogen in the air". Finally, 35 per cent of students chose the correct answer to the question on condensation, that water in the air sticks to the outside of the glass jar; 41 per cent chose the incorrect answer that condensation on the outside of a glass of ice was caused by coldness making oxygen and hydrogen form water. Over 30 per cent of students chose the answer that mentioned elemental oxygen and hydrogen, even thought they were the wrong answers, in all three questions. It is possible that, as Gunstone et aL (1992) suggest, students are answering with what appeared to be the most 'scientific' answer of the three choices.

Water Questionnaire Frequencies of responses to each statement were computed. A number of models were specified and confirmatory factor analyses (JSreskog & SSrbom, 1989) conducted to test these models. None of the models was congruent with the data, which suggests that the students in this sample do not have well-defined conceptual structures about water-related phenomena. Responses to individual items, however, can provide teachers with useful 'snapshots' of student conceptions.

CONCLUSION

Osborne and Cosgrove (1983) suggest that many students appear to understand scientific concepts by using the correct scientific terms when discussing concepts, but cannot elaborate further when probed. This was confirmed in our study. In particular, students appear to focus on [elemental] oxygen and hydrogen in questions about water, no doubt because they remember that water is H~O. This leads some of them to look for these two elements as cues to the perceived correct answer.

The interviews provided valuable insights into the students' conceptions of water- related phenomena. However, such interviews are time consuming. For classroom teachers, the 34- item water questionnaire may provide an alternative (even if limited) probe to the more time-consuming interviews. Frequencies of student ratings of the 34 statements can provide an indicator of students' certainty about the conceptions they hold. The multiple choice question approach is another alternative. We have recently developed a set of multiple choice items based on student interview data. These items, like the three from Osborne and Cosgrove (1983) may provide another probe into student understanding which will be of benefit to classroom teachers.

A recently-published variation on these approaches is to combine the multiple choice format with ratings. Rowell, Dawson and Madsen (1993) suggest offering students a multiple choice format in which students rate each response, rather than choosing one response only. This approach is similar to our Water Questionnaire approach. These varied approaches can, together, contribute to our understanding of conceptions of important physical phenomena, in this case, water-related phenomena. Some of these probes may be of particular use to classroom teachers.

Acknowled.qement We thank all students, teachers and administrative staff at each of the five schools that assisted us in this project.

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AUTHORS

DR RENATO SCHIBECI, Senior Lecturer, School of Education, Murdoch University, Murdoch, WA 6150. Specializations: educational technology and the teaching-learning process; public understanding of science and technology.

TONY FETHERSTONHAUGH, Doctoral candidate, Department of Science Education, Edith Cowan University, Perth, WA.

SUSAN GRIFFIN, Research Assistant, School of Education, Murdoch University, Perth, WA.