Linda Webb and Ian Morrison

School Science Review, March 2000, 81 (296) Pages 99-103

Primary school children do not hold a consistent view of the direction of gravity. Two models of thinking are explored within the context of the National Curriculum for Science

ABSTRACT This article reports a small-scale study of primary school children's ideas about the direction of gravitational force. Previous research from other sources had suggested that there were up to six different views held by children and that it was difficult to identify a 'view' held by the majority of children. This research found that two views were commonly held, including the scientific model, but, more importantly, that the majority of pupils did not use a model consistently. We argue that this casts doubt on the most popular assumptions of constructivist practice in primary science education. The research was carried out within the context of the National Curriculum for Science in England and Wales.

A result of the implementation of the National Curriculum for Science in England and Wales (DES, 1989a) was that all children, including those in primary schools, learn astronomy. The revisions (DES, 1991) further strengthened the place of this topic, entitled 'The Earth's place in the Universe', especially at key stage 2.

The Science Processes And Concept Exploration (SPACE) project (Osborne et al., 1994) reported on how primary age children understood the various concepts, including the force of gravity, in this area of the curriculum now called 'The Earth and beyond'. It suggested that teachers should be properly sceptical of the detail within the National Curriculum for Science. The data in the study described in this article support the view that it is difficult for many pupils at the upper end of key stage 2 to achieve a consistent, scientific view of the world and how it works against the pull of 'common-sense' evidence. Indeed, the results support the view that there is a period when pupils can hold, simultaneously, two alternative or contradictory models. This article places the research methodology and findings in the context of other studies and draws out implications for teaching and the curriculum.

Ausubel (1968: vi) encapsulated the research/l earning process in the following quotation:

The most important single factor influencing learning is what the learner already knows. Ascertain this and teach him accordingly.

Similarly the National Curriculum non-statutory guidance (DES, 1989b) states that 'They (the pupils) bring these informal ideas into the classroom...'. From the early 1980s there was a growing body of research proposing 'alternative frameworks', obtained by I interviews about instances' and other techniques. This led to evidence of the various conceptions that children hold about the world around them. Suggestions for teaching, based on the constructivist model of learning, appear in a number of publications, including the Children's Learning in Science project (CLIS) reports (e.g. Brook and Driver, 1984; Brook et al., 1984) and the SPACE reports (Osborne et al., 1990, 199 1). For example, the Nuffield Primary Science scheme (1993) was developed from the findings of the SPACE project. Hodson (1998) provides a useful summary of the main features of the various constructivist approaches to science teaching:

Constructivist approaches generally involve creating opportunities for students to make their own ideas explicit, share them with others, subject them to critical scrutiny and test their robustness by observation and /or experiment. (p. 3 5)

In the literature there are intriguing descriptions of children's perceptions of gravity. The idea most commonly held by young children and also by some adults is that the world is represented with Britain and the north at the top and Australia and the south at the bottom. This response is understandable for those whose idea is that the Earth is a sphere and that there is an absolute Earth- independent 'up-down' direction in cosmic space. The focus of the study is to investigate the use of this model and the scientific model of gravitational force with respect to the Earth and to see how consistently the two models are held by the children.

It is evident from reading the research findings that it is very difficult to identify a 'view' held by the majority of the children. For example, Nussbaum (1985), using a pencil-and-paper test to research the

'Earth in space', concluded that there are five qualitatively different notions or beliefs. Baxter (1989) identified four notions, one of which can be identified as an amalgam of two defined by Nussbaum. He later used this to propose a constructivist model for the teaching of astronomy in the National Curriculum (Baxter, 1991). Vosniadou and Brewer (1992) cited similar notions to those of Baxter. Arnold, Sarge and Worrall (1995) identified six different notions. As the research instruments were different in each study, and the notions were derived from different sets of information, it is difficult to make direct comparisons of these findings. In any case, as Solomon (1994) has suggested, even while it has identified children's understandings, constructivism has often 'skirted around' the issue of how to teach the established body of knowledge. Solomon likens this process of learning to I arriving on a foreign shore', or 'struggling with conversation in an unknown language' (p. 16). According to Solomon, it is essential that we recognize that 'children's ideas' and 'established scientific theories' are of an entirely different nature. Scientific theories are established through a collaborative and collective enterprise. It is therefore inevitable that children will find:

... that words are used in new but standardised ways: problems which were never seen as being problems are solved in senses which need to be learnt and rehearsed. For a time, all pupils may feel that they are on a foreign land and no amount of recollection of their own remembered territory with shut eyes will help them to acclimatise. (p. 16)

This article reports a small-scale study of primary school children's ideas about the direction of the gravitational force as a concept in the 'Earth in space'. The pencil- and-paper test was based on the work of Nussbaum and Novak (1976), Nussbaum (1979,1985) and Baxter (1989), and sought to find out which of the notions were held by 10- 11 year-old pupils, and how consistently those notions were held. The study was conducted in a class of 26 pupils in a mixed rural primary school. There were eight questions in the test and pupils were allowed to take as long as they wished ' I They were encouraged to ask for help if there was a part of the test they did not understand. The test was administered in April 1995, just before the SATs, and so the class had recently revised this section of the curriculum. It should be noted that none of the teaching or revision had been in a 'constructivist' manner.

Since the research was carried out, the National Curriculum for Science has been further amended. The 'Earth in space' is now described as 'The Earth and beyond'. This section focuses on knowledge of the Sun, Earth and Moon as being spherical, about periodic changes in, for example, the length of the day, and about shadows. Under 'Forces and motion' pupils should be taught that objects have weight because of the gravitational attraction between them and the Earth. Attainment target 4 says that 'They [the pupils] make generalizations about physical phenomena, such as motion being affected by forces, including gravitational attraction'.

The proposed changes to the National Curriculum from September 2000 onwards have now been published (QCA, 1999). At key stage 2 there is still a section on 'The Earth and beyond' and under 'Forces and motion' the statement has been only slightly modified to read 'pupils should be taught... that objects are pulled downwards because of the gravitational attraction between them and the Earth.'

Accordingly, it would seem that this research and that reported elsewhere is still directly relevant to the current National Curriculum in England and Wales. This research is about the way the Earth is represented with North at the top and Australia at the bottom. It is also about gravitational forces, and weight, always acting towards the center of the Earth. In England these two views partially overlap. In the southern hemisphere, using a conventional globe, they do not. The pupils' response in England is understandable as common language includes such expressions as 'down south'.

This article will refer to questions 2, 3, 4 and 5 (questions 1, 6, 7 and 8 were about more general notions to do with Earth and space and are not especially relevant to this discussion) and these, together with the results, are reproduced in Box 1. In analysing the results the following two models of the Earth in space were employed. They are shown in Figure 1.

From questions 2, 3 and 4 it was found that 17 (65 %) of the pupils held a consistent 'up-down' model on all three questions, while 6 (24%) consistently held a scientific model. The remaining 3 pupils (I I %) held no model consistently on all three questions. Interestingly, in this latter group some pupils were able to show the ball falling correctly at the South Pole, but from a person standing in the down position.

Question 5, showing tunnels drilled through the Earth, brought a different set of responses from many of the pupils. The number using the scientific model increased substantially to 12 (46%), the 'up-down' model was used by only 3 (12%), while the number using different models within the question increased to 11 (42%). Seven in the last group correctly responded that a ball will fall from the South Pole to the center of the Earth. However, when confronted with a ball at the Equator they invoked the scientific model combined with an 'up-down' model, i.e. the ball traveled in an oblique tunnel. It appears that they were unable to totally reject the 'up-down' model but combined it with some notion of gravity. It is as though they are combining two forces, one real and one intuitive.

Across these four questions only 7 (27%) of these year 6 pupils used a model consistently. Four pupils used the scientific model throughout and three pupils used the 'up-down' model on all questions. One pupil used the scientific model for questions 2, 3 and 4 but abandoned it for question 5. By contrast six pupils (23%) used the 'up-down' model for questions 2, 3 and 4 and the scientific model for question 5. So the largest category of children (73%) is the group which does not hold a consistent model for the direction of gravity.

The results show that relatively few of the pupils tested (27%) used a model consistently and, of these, fewer, only 15%, used the scientific model throughout. These results are supported by other research. Nussbaum and Novak (1976) represented the Earth as a simple sphere and found that 22% of Year 6 pupils opted for a radial model, i.e. they showed the balls falling radially towards the center of the Earth under gravity. The SPACE research (Osborne et al., 1994) used similar items but the drawing of the sphere included continents. They found that some 55% of upper junior children invoked this scientific model, possibly assisted by the more realistic drawings of the Earth. The difference in the findings of Nussbaum and Novak compared with those from the SPACE project may also be due to the fact that the former used more items, and, in testing the pupils more exhaustively, may have identified pupils for whom the models and especially the scientific model were not firmly embedded.

In the study reported here, the percentages whose views were in the scientific domain and those who were consistent in the 'up-down' model are also much lower. There are two possible reasons for this. As with the findings of Nussbaum and Novak, increasing the number of questions, and hence the number of situations, may have led the children to question their own notions. Secondly, research undertaken by the SPACE team about children's ideas on electricity showed that the teaching of circuit concepts to primaryage pupils led to an increase in the lack of consistency. Young children's notions are easily disturbed and the test pupils in this study had revised this topic in preparation for national testing. Research previously undertaken by one author (Webb, 1983) also in the field of electricity, showed that children worked with a model until they met a conflicting real-life situation, whereupon many then abandoned the scientific model.

So previous research evidence and this study suggests that the development of scientific thinking in top junior school pupils may be fragile.

Driver and Easley (1978) report on children who were presented with counter examples and conflicting evidence in order to challenge their existing conceptions. It was found that this did not, in itself, encourage a change in pupils' thinking and at times only produced confusion. It may be that in a typical upper primary class, many are in the transition from intuitive ideas to those in accordance with the scientific model and that the breadth of questions asked, and recent teaching, may lead to inconsistencies, examples of which have been reported here.

It may be that if we accept Solomon's (1994) powerful arguments regarding the essential differences between pupils' ideas and scientific theories then we also have to accept that children learn science because they can simultaneously hold conflicting views rather than despite it.

The challenge for teachers is to explore, in detail, the way pupils are thinking, and to try and understand the logic that governs their notions. What are the questions posed by the teacher and what are the scientific examples presented to the pupils which will help them acquire a consistent set of scientific strategies for understanding the world? It may be that the development of the next National Curriculum for pupils should include teaching materials to support teachers in this task.

Ian Morrison wishes to acknowledge the contribution of the local primary school in which Linda Webb carried out this research and is grateful to those colleagues who supported him in completing this article.

Arnold, P., Sarge, A. and Worrall, L. (1995) Children's knowledge of the Earth's shape and its gravitational field. International Journal of Science Education, 17(5), 635-641.

Ausubel, D. (1968) Educational psychology: a cognitive view. ) New York: Holt, Rinehart Wilson.

Baxter, J. (1989) Children's understanding of familiar astronomical events. International Journal of Science Education, 11(5), 502-513.

Baxter, J. (199 1) A constructivist approach to astronomy in the National Curriculum. Physics Education, 26(l), 38-45.

Brook, A. and Driver, R. (1984) Aspects of secondary students' ideas about energy: full report. Leeds: The University of Leeds.

Brook, A., Briggs, A., Bell, B. and Driver, R. (1984) Aspects of secondary students' ideas about heat: full report. Leeds: The University of Leeds.

Department of Education and Science/Welsh Office. (I 989a Science in the National Curriculum. London: HMSO.

Department of Education and Science/Welsh Office. 1989b) Science in the National Curriculum: Non-Statutory guidance. London: HMSO.

Department of Education and Science/Welsh Office. (199 1). Science in the National Curriculum. London: HMSO.

Driver, R. and Easley, J. (1978) Pupils and paradigms; a review of literature related to concept development in adolescent science students. Studies in Science Education, 5, 61-84