A study of the effect of sensorimotor experiences on the retention and application of two fundamental physics ideas.

Abstract

The primary objective of this study was to investigate whether sensorimotor experiences can help young students ages 9 to 10 to construct a mental model involving a relationship between the speed of the molecules of a substance and its temperature. The sample consisted of 86 children who were randomly assigned to two groups. The children of the first group were presented with photographs and animated pictures regarding the motion of "little balls"--the molecules--in various con texts, while the children of the other group participated in sensorimotor activities regarding the same contexts. For the assessment of children's understanding, six tasks involving visual material (photographs and animated pictures) were used. This procedure took place one week after the treatment and again four weeks later. The significant difference that was found through a t-test between the two groups on both occasions, the correlation coefficients between the scores on the two tests for both groups, and the effect sizes provide s upport for the effectiveness of the treatment based on sensorimotor activities as far as the development of the aforementioned relationship is concerned. Further research is warranted to confirm whether these findings can be generalized over to other populations and other science concepts.

Introduction

Over the last two decades, empirical studies in the area of science education have provided evidence that mental models play a major role in the thinking of children and adults alike (Hadzigeorgiou & Williams, 1998; Holland, Holyoak, Nisbett & Thagart, 1987; Nussbaum & Novak, 1976; Viennot, 1979; Vosniadou & Brewer, 1992; Vosniadou & Kempner, 1993). The role of sensorimotor experiences in the development of these mental models has been postulated (Driver, 1984; Hadzigeorgiou, 1994), while the notion of "somatic understanding" has begun to be considered as an important form of understanding with implications for pedagogy (Egan, 1997). Gardner's (1983, 1989) theory of multiple intelligences (with the bodily-kinesthetic being one the eight intelligences) also provides support for the idea that movement is an indispensable part of thinking and learning (Hannaford, 1995).

The fundamental idea in Johnson's (1987) book The Body in the Mind: The Bodily Basis of Meaning, imagination and Reason is that almost all of our knowledge derives from bodily experiences through metaphorical projections into abstract domains. According to Johnson (1987), bodily motion and forces give meaning both to our physical experiences at a preconceptual level and to many abstract concepts of our language through the use of metaphors. Drawing on the work of several researchers and philosophers, Johnson argued that the most fundamental of all concepts are those of force and motion, which, through bodily experiences from the day we are born, develop into various mental models such as those of compulsion, blockage, contact, attraction, balance, equilibrium, in/out orientation, containment, trajectory, and so forth. Even emotions like anger are said to be represented through a schema involving a fluid within a container that bursts open. Furthermore, our experience of symmetry is not in our perception of s ymmetrical objects but, instead, in our experience of bodily balance.

Johnson (1987) uses the term "schema" instead of mental model and argues that schemata, as structures for organizing and understanding the world, "fall between abstract propositional structures ... and particular concrete images" (p. 29); however, these schemata can also "constrain our meaning and understanding" (p. 138). There are several empirical studies on students' misconceptions that provide support to Johnson' s arguments, especially in the area of mechanics. The intuitive idea that "motion presupposes a net force," for example, derives from a mental model (or a schema) that has been developed through early sensorimotor experiences (being pushed or pulled in various directions) or experiences involving the pulling and pushing of objects (see Hadzigeorgiou, 1994, for an overview). This mental model--force in the direction of motion--does indeed constrain scientific understanding.

As an ERIC search revealed, at this point, no empirical study was actually done to test the effectiveness of a teaching strategy based upon sensorimotor activities with regard to physics concepts (not skills). It would, therefore, be interesting to investigate, on the one hand, whether certain scientific ideas can be introduced through sensorimotor activities that will, in turn, lead to the development of models that "contain" these ideas, and, on the other hand, the range of the application of such models. The investigation of the effect of sensorimotor experiences on the development of mental models is, therefore, interesting from both a theoretical and a practical point of view. This investigation represents a pilot study and a preliminary evaluation of the effect of sensorimotor experiences on the understanding and retention of certain concepts and ideas. It also represents a sample of the work done by the Mechanics in Action Group at the University of Leeds, England.

Purpose of the Study

The purpose of this study was to investigate the effect of sensorimotor experiences on the retention and application of the following two fundamental ideas from the area of physics:

1. The temperature of a substance is related to the (average) speed of the molecules (the higher the speed the higher the temperature).

2. A certain type of molecular motion is characteristic of the state of the substance. (In solids, molecules move about in a fixed position; in liquids, the molecules can move around freely with small speeds; and in gases, they move with high speeds.)

These ideas represent an "intellectually honest way," to borrow Bruner's (1966) words, to introduce the particulate model of matter and the idea that "the temperature of a substance represents a measure of the average kinetic energy of its molecules." The presentation of these ideas took place through the use of iconic representations for one group and enactive representations for another group.

Research Questions

1. Can students construct a mental model involving a relationship between the speed of the molecules and the temperature of a substance?

2. Can students differentiate between the type of the molecular motion and the type (state) of the substance (i.e.. solid, liquid, and gas)?

3. Does the mode of information presentation have an effect upon students' remembering and applying the two physics ideas?

Research Design

Sample

The subjects of this study were 3rd-grade students (ages 9 to 10, average age 9 years and 4 months) from four elementary schools (one 3rd-grade class per school) located on the eastern outskirts of Athens, Greece. A total of 86 students--42 females and 44 males--took part in the study. All students came from middle-class families with no essential variation in their socioeconomic status, race, and religion. As a preliminary interview revealed, the students had no prior knowledge about the particulate model and molecular motion. (They are introduced to such concepts in the 6th grade.) Only two students knew something about "little balls" inside solids and gases. These two students were included in the groups and participated in both the presentation of the ideas and the assessment procedure, but were not included in the sample.

Procedures

The research took place in four elementary schools. A two-group design was used (Borg & Gall, 1989; Cohen & Holliday, 1979; Cohen, Manion, & Morrison, 2000). The 3rd-grade students of each school (23, 17, 19, and 28, respectively) were randomly assigned to two groups. The students of the first four groups (11, 9, 10, and 14 respectively) of each school (total number N1=44) formed the "iconic group." These students were introduced to the two fundamental physics ideas through pictures (photographs) and animation (e.g., moving balls on a VCR). The students of the other four groups (total number N2=42 since there was one loss during the assessment procedure) formed the "enactive group." These students were introduced to the same ideas through sensorimotor activities.

The research lasted four weeks. The presentation of the ideas took place during the first three weeks, with a posttest being administered on the Friday of the fourth week. No pretest was used since a preliminary interview revealed that only two students knew something about "little balls" inside solids and gases. A second posttest was administered four weeks later (i.e., eight weeks after the presentation of the ideas). Because it was possible that something unrelated to this study could happen to the groups in those four weeks that would allow them to further understand and remember the concepts involved, attention was paid to the control of the variables (e.g., no reference was made to the ideas relating to the study by the teachers; information was obtained on a daily basis on what students learned outside the school).

The 3rd-grade teachers from each school took the last period of the schedule on Thursdays and Fridays in order to present the two ideas. The first group (in all four schools) were presented with the ideas on Thursdays and the second group on Fridays. A previous arrangement existed between the teachers and the participants of both groups, so that only one group was present in the classroom when the introduction took place.

During the presentation of the ideas, the teachers (one teacher per school) did not attempt to clarify students' ideas about the phenomena presented through the activities. Although the teachers did help students to observe and make the appropriate connections (iconic group), and did explain to them the game they would play (enactive group), they did not provide further explanations about what students were watching or doing. This was done in order to minimize the effect of language (symbolic representation). All four teachers who participated in the study followed the same procedure during the presentation of the ideas. This way the effect of teaching style on students' understanding was controlled for.

The assessment procedure took place in the four schools that students attended on the Friday of the first week after the presentation of the ideas. Given the limited time available (around 50 minutes) and the number of students (23, 17, 19, and 28, respectively), the assessment procedure took place in two classrooms. The steps that were followed were as follows:

Each student (from either group--iconic or enactive)...

* watched both a photograph and an animated picture on a VCR (so that motion and not only a static picture could be actually observed).

* listened to a question related to the animated pictured that was watched (asked by the teacher).

* read the question that was asked (and the teacher made sure that the student did understand the question).

* thought about the question and then responded orally to the teacher.

This was done with each student who, after he or she responded to all tasks, left the classroom and went to the courtyard. In this way, only one student and the teacher were present in the classroom. The students who were waiting to enter the two rooms had no contact with those who had finished with the test. They were all in a room participating in a project that they had chosen to do while waiting to be called to go to one of the two rooms.

Each student was allowed three minutes to think about each task (included was the time the teacher took to ask questions in order to probe students' understanding), after he or she had watched the animated picture and after he or she had listened to the related question, before he or she could move on to the next task. The animated picture, however, could be watched during those three minutes. The student's response and explanation had to be given before he or she could proceed with the next task.

Each question was scored as one point, so that the minimum score a student could get was 0 and the maximum score was 6. Always an explanation of the answer was required, otherwise the student scored zero in that question. A response to any question was considered "right" (and, therefore, the student got one point) when the student could answer, for example, one of the following three questions (see Tasks 1 and 2):

1. Which one of these glasses contain water (or air)?

2. Why do you say so?

3. What difference do you think there is between this glass and the other one(s)?

It should be pointed out that although reference to liquids and gases was made, water and air were used for most activities (in treatment and assessment), since for young children these are prototypes for a liquid and a gas respectively. This means that for young children, water and air represent many liquids and gases respectively (Krnel, Watson, & Glazar, 1998).

The activities used for the presentation of the two ideas for each group, and the tasks for assessing students' ability to apply these ideas and remember them are given below.

Activities Used for the Presentation of the Ideas

1. The Transformation of Ice into Water, and the Water into Vapour

Iconic Group

The students observe a simple demonstration: a piece of ice is placed in a pan and on a gas burner. After some minutes (depending upon the quantity of the ice), the ice is transformed into water, and then the water is transformed into vapour that can be easily observed. After this demo-activity, the teacher uses photographs and animation on a video to illustrate the experiment. Both the normal photographs and the animated ones present the piece of ice as consisting of little balls--the molecules--that are very close to one another, and which start to "break apart" when the temperature of the ice starts to increase and the ice melts. When all the little balls of the ice break apart, all the ice has changed into water. As the water gets hotter and hotter, the little balls are moving faster and faster "strolling around" inside the pan (or beaker). When the speed of these little balls becomes very high, they start to leave the pan until all of them escape into the air.

Enactive Group

The students are invited to play two games. For the first game, the students are divided into three groups. The first group is the "ice group," the second group is the "water group," and the third group is the "vapour group." The teacher tells the students that the ice, the water, and the vapour contain little things which have a name: molecules. The students will then play with these little things. In the ice group, the children move about their position (without taking any steps); they wear a coat and pretend that they feel very cold. In the water group, students walk after they take off their coat; and in the vapour group, children take off even their T-shirt, pretending that it is very hot. The teacher has made three large circles for each group to stand in. The children in the water group are not allowed to go beyond the circle, while in the vapour group the children can leave the circle.

For the second game, all students start out as the molecules in the ice, then they change into water, and then into vapour. As more heat goes into the ice, the movement of children (the molecules) increases and, at some point, when they hear the command "melt," they start breaking apart and moving about the pan until all molecules do so. The more heat that goes into the water, the faster the movement of the children (the molecules). The students gradually increase their speed, and upon the command "evaporate or turn into vapour," they move faster and leave the pan. Children, while acting as the molecules of water, one by one start taking their sweaters off.

2. The Mixing of Two Glasses of Water of Different Temperatures

Iconic Group

The teacher uses animated pictures to represent one glass of hot water and one glass of cold water. The teacher helps students observe the difference between the molecules in the two glasses (by asking questions about how the molecules differ in the picture and in what ways), and tells them that as the temperature of the water rises, the motion of the molecules increases as well. The teacher also helps students to observe the difference between the initial two glasses and a third one into which the two initial glasses were emptied. The teacher helps students link the temperature of the water with the speed of the molecules.

Enactive Group

Students are invited to form two groups: one group to represent the "cold glass of water" and the other group the "hot glass of water." The teacher tells them that in the hot glass the molecules move very fast (students run), and in the cold glass the molecules move very slowly (students walk). When these glasses are emptied into another glass, the molecules would go neither too fast nor too slow (students jog).

3. The Expansion of a Piece of Wire

Iconic Group

The teacher shows students photographs of three pieces of iron wire at three different temperatures. He or she helps students to observe the difference in their length, and then presents them with an animated picture (on a VCR). This picture shows a one-dimensional motion of molecules inside a wire at different temperatures so that students observe the fact that as the temperature rises, the molecules move farther apart and the length of the wire increases.

Enactive Group

The teacher invites the students to represent an iron bar at various temperatures. He or she tells them to form one line with the students all standing next to each other (shoulder to shoulder). As the temperature of the bar increases, the distance between the students increases a little. Upon the commands "hotter" and "colder," the length of the bar should increase or decrease respectively.

4. The Melting of a Piece of Iron

Iconic Group

The teacher plays a videotape showing the melting of iron. He or she then uses animated pictures to represent this process. The model used consists of four parallel lines of little balls (molecules) moving (oscillating) about their equilibrium position. As the temperature increases, the movement increases; at a certain temperature the molecules start "breaking apart" and the solid iron turns into liquid iron.

Enactive Group

Children are invited to play the above process. They form three parallel lines, with four to five children in each line. This configuration represents a piece of iron which is placed inside an oven. Children are continually moving from left to right and from right to left, but without leaving their position. As the temperature in the oven increases, the movement becomes more and more rapid. When the children hear the word "melt," they start moving around in all directions (but without leaving the oven).

5. Seeing Inside Solids, Liquids, and Gases

Iconic Group

The teacher shows photographs and uses animated pictures on the VCR to present the differences among solids, liquids, and gases (air). The teacher helps students focus on the differences that can be observed regarding distances between molecules, and the type and speed of the molecules' movements.

Enactive Group

The teacher invites students to play "solids, liquids, and gases (air)." She or he tells the students the rules of the game, that is, how they form the solid or the liquid, the way they move, and how fast they move. In the case of the solid substance, children form three lines, and they oscillate about their fixed position. In the case of the liquids, the children have no definite arrangement and can walk in every direction, "rubbing shoulders" with one another when they come into contact. The only constraint is that they cannot leave the glass or the container in which they are (this has been drawn on the floor or ground) unless they start walking too fast, which happens when the temperature of the liquid increases. In the case of a gas (air), the children must jog inside a bottle and collide with one another, leaving the bottle when they are very near its open mouth.

During the presentation of the ideas for both groups, the teacher did not attempt to clarify students' ideas about the phenomena presented through the activities. Although the teacher did help students to observe and make the appropriate connections (iconic group), and did explain to them the game they would play (enactive group), he or she did not provide further explanations about what students were watching or doing. This was done in order to minimize the effect of language (symbolic representation).

Assessment Tasks

The tasks that were used for the assessment of students' understanding of the ideas and the range of their application are given below:

Task 1: Students are presented with three glasses and are asked to identify which one contains water and which one the solid substance (two of the three glasses contained water at two different temperatures and the third one contained sand).

Task 2: Students are presented with three glasses and are asked to identify the glass containing hot water. (One glass contained cold water, one hot water, and the third one hot air.)

Task 3: Students are presented with three bricks and are asked to identify which one is in the oven (the other two are in the freezer and outside the fridge).

Task 4: Students are presented with two identical glasses of water containing hot and cold water. Then they are asked to identify out of a number of glasses the one containing the water resulting from the mixing of the two initial glasses.

Task 5: The students are presented with a metal bar whose one end is over a heater and the other end inside a bucket filled with ice. They are asked to identify which end is inside the ice. (They can observe the oscillation of the molecules along the bar.)

Task 6: Students are presented with five bottles containing water (three of them) and air (two of them) at different temperatures. They are then asked to identify the bottle containing cold air.

Results and Discussion

A t-test for independent samples was utilized for the comparison of the scores of the two groups. The data were analyzed using the SPSS 10 statistical analysis package. The results of the t-test led to the rejection of null hypothesis since statistically significant differences between the "iconic" and the "enactive" group were found both immediately after treatment and four weeks later (see Tables 1 and 3). This statistical significance certainly provides evidence that the difference was caused by the treatment. The effect size (as the difference between the enactive and iconic group means expressed in SD units), however, provides additional evidence of the effect of the treatment (Cohen et al., 2000; Rennie, 1998), since its value was found 0.83 and 1.2 for the first and the second test respectively (see Tables 1 and 3). These values are much higher than 0.4 which is considered an average effect size (Fraser et al., 1987).

In looking at the data, several comments can be made in regard to the research questions. In regards to the first question, the idea that the temperature of a substance is related to the speed of its molecules was more remembered and applied than the idea that a certain type of molecular motion is characteristic of the state of the substance (see Table 2, Tasks 3 and 5 for both groups); however, as far as the second research question is concerned, the students from both groups had difficulty in differentiating between molecular motion in water (a liquid) and air (a gas). The students of the iconic group had more difficulty in making this differentiation. As can be seen in Table 2, a lot of students from the iconic group and most students from enactive group could respond to Tasks 3,4, and 5 but not to Tasks 2 and 6. Task 3 appeared to be the easiest to answer, while Task 6 was the most difficult of all six tasks. This provides evidence that students indeed had difficulty in differentiating between molecular motion in a liquid (water) and molecular motion in a gas (air). Yet in comparing the number of students who responded to this particular task (as well as to Task 2), it appears that the enactive group had an advantage. As shown in Table 2, only five students from the iconic group (11. 4%) could respond to Task 6 compared to 16 students (38%) from the enactive group. In addition, only 11 students (25%) could respond to Task 2 compared to 26 students (62%) from the enactive group.

Generally, in comparing the two groups, it can be said that more students from the enactive group could apply the two fundamental ideas (e.g., the conceptual link between motion and temperature as well as the idea that matter consists of little particles moving in different ways and with various speeds depending upon the state of the matter) in different situations. This provides evidence that those students did develop mental models through their participation in sensorimotor activities, since all of them could provide an explanation and justify their answers (Collins & Gentner, 1992). For example, they could say that one bottle contained water or air because the "little balls" inside it moved in a particular way and with high or low speed, which was different from the motion and the magnitude of speed of the "little balls" in another bottle.

The significant difference that was found through a second posttest (with the same assessment tasks), which was administered four weeks after the first test-that is, eight weeks after the presentation of the ideas-provides additional evidence that participation in sensorimotor activities resulted in the development of mental models (see Table 3). Half of the students of the iconic group (51.2%) could not answer the tasks compared to 22.5% of those from the enactive group (see Table 4). Furthermore, while no student from the iconic group could respond to Task 6, there were nine students from the enactive group who did respond to it (see Table 2). Of course, it is quite interesting to note that eight of those nine students could respond to all six questions (see Table 4). One student of those nine students did not respond to Task 2. From the enactive group, 14 students could respond to Task 2 compared to four students from the iconic group. It is also interesting to note that 47.5% of the students of the enacti ve group had a score greater than three points compared to 12.2% of the students of the iconic group.

It deserves to be mentioned that in Task 6, students were deliberately presented with five, instead of three, bottles. It was thought that this would complicate things and that the three minutes that students had in order to think and respond to this particular task would not be enough. Yet, those nine students who did respond correctly to Task 6 (see Table 2) could easily identify "the cold air," explaining at the same time that the motion of the molecules ("the little balls") was different in that particular bottle and that the speed of the molecules was not as high as in the other bottle that also contained air. These students could easily differentiate between the motion of water molecules and the air molecules. This was something that was difficult for the students of both groups.

It should be pointed out that the tasks used for the assessment of the retention and the application of the ideas were animated pictures. It appeared that this would give the iconic group an advantage. The results do provide evidence, however, that sensorimotor activities helped the students of the enactive group to construct a relationship between speed and temperature which they used in a context involving purely iconic representations (e.g., see Table 2, Tasks 2 and 6 for both posttests). This effectiveness cannot be disputed despite arguments that the interpretation of the results becomes problematic due to the fact that the assessment was based only upon iconic material. Of course, there is a limitation--and this is what can make the interpretation of the results somewhat problematic--since some other variables were involved in the treatment of the enactive group (e.g., the simulation of heat by children who were taking their clothes off). This also provides support for the effectiveness of using childre n's own bodies instead of photographs or animated pictures.

Given that the correlation coefficients between the scores of the first and second test were found to be 0.8 and 0.7 for the iconic and the enactive group respectively, the effect of the treatment cannot be disputed. The effect size of 1.2 for the second test does provide additional evidence for the effect of the treatment. The results of this study, therefore, are encouraging for further research into the utilization of sensorimotor experiences as a means to presenting science material; however, further research is needed to confirm whether such findings can be generalized over to other populations and other science concepts.

With regard to the present study, it would be interesting to investigate the effect of color on the construction of mental models (e.g., students playing "cold water" could hold blue ribbons while students playing "hot water" could hold red ribbons, or the area on which they are standing and moving could be painted blue and red respectively). Wave motion is another area that could be researched, as well as the area of electricity in which the effect of sensorimotor experiences on the understanding of such concepts as electric current and resistance would be also worth investigating. In the area of mechanics, the effect of sensorimotor activities may certainly appear more obvious. Newton's third law (action and reaction), transference of momentum, equilibrium, and stability are among the topics that provide fruitful ground for investigation (Hadzigeorgiou, 1987. 1994). In a study with very young children (ages 4 to 5), participation in sensorimotor activities (e.g., walking on a balance beam while carrying, f irst with one hand and then with both hands, buckets of different and the same weight) did help with the construction of a mental model for mechanical equilibrium (Hadzigeorgiou & Williams, 1998).

Given the evidence that human knowledge has characteristics which are attributed to procedural (knowing how) rather than to declarative (knowing that) systems (Rumelhart & Norman, 1981), as well as the important role of enactive representations and modelling in children's thinking (Ackermann, 1999), the idea of utilizing sensorimotor experiences should be seriously considered in planning curriculum activities, particularly for early childhood science education. In view of the notions of "learning style" (Kolb, 1985) and "multiple intelligences" (Gardner, 1989), however, learning episodes in the form of activities involving the child's own body, and which are designed in such a way that they contain unambiguously general ideas, appear to be a potential educational tool in the hands of teachers even in the case of older students.

If the process of concept development involves the construction of relationships among concepts (Case, 1985; Hadzigeorgiou, 1997; Novak & Gowin, 1984; Prawat, 1989) and this process does not always lead to the construction of the accepted (from a scientific point of view) relationships, as research with students of all ages has shown (Novak & Gowin, 1984; Reif & Larkin, 1991), then it would be wise that children be given opportunities to construct such relationships at an early age. Sensorimotor experiences provide the starting point, no doubt. In such a case, the curricular implication would be the consideration of a spiral curriculum in which certain scientific ideas are introduced through sensorimotor activities at an early age before they are introduced more formally later on. Of course, there needs to be enough evidence--not just arguments--that sensorimotor activities do have a significant effect upon children's learning performance. This study certainly provided such evidence but, as has already been said, further research is needed before any generalizations can be made.

Table 1

T-Test Results for the First Posttest

Sample    N   Mean   SD

Iconic    44  2.41  2.04
Enactive  42  4.12  1.92

t (83.98) = -4.011; p< 0.001, effect size = 0.83
Table 2

Number of Students Responding Correctly to the Tasks Immediately after
Treatment (A) and Four Weeks Later (B)

         Iconic Group       Enactive Group
         A         B         A         B
Task   N   %     N   %     N   %     N   %

1     22  50.0  10  24.4  33  78.6  24  60.0
2     11  25.0   4   9.8  26  61.9  14  35.0
3     29  65.9  19  46.3  37  88.0  29  72.5
4     18  40.9  11  26.8  32  76.2  21  52.5
5     21  47.7   8  19.5  33  78.6  25  62.5
6      5  11.4   0   0.0  16  38.0   9  22.5
Table 3

T-Test for the Second Posttest

Sample     N  Mean   SD

Iconic    41  1.27  1.63
Enactive  40  3.25  2.33

t (69.63) = -4.429; p< 0.001, effect size = 1.2
Table 4

Number of Students and Their Scores Immediately after Treatment (A) and
Four Weeks Later (B)

          Iconic Group      Enactive Group
          A         B         A        B
Score   N   %     N   %     N   %    N   %

0      12  27.3  21  51.2   4   9.5  9  22.5
1       6  13.6   5  12.2   1   2.4  4  10.0
2       2   4.5   6  14.6   1   2.4  3   7.5
3      13  29.5   4   9.7  10  23.8  5  12.5
4       3   6.8   2   4.9   4   9.5  2   5.0
5       3   6.8   3   7.3   8  19.0  9  22.5
6       5  11.4   0   0.0  14  33.3  8  20.0

Manuscript accepted March 26, 2001.

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Correspondence regarding this article should be directed to

Yannis Hadzigeorgiou

Assistant Professor

Department of Education

University of the Aegean

Rhodes, Greece

[e-mail]