naive knowledge and the design of science museum exhibits

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36/3 1993 Naive Knowledge and the Design of Science Museum Exhibits MINDA BORUN, CHRISTINE MASSEY, AND TIIU LUlTER ABSTRACT The Naive Knowledge Study at the Franklin Institute Science Museum in Phila- delphia, Pennsylvania, took place over a three-and-one-half-yearperiod ending in April 1992. It was both a research and application project to uncover widespread misconceptions about the concept of gravity held by museum visitors and to test the efficacy of hands-on exhibits in altering these naive notions. Exhibits were designed to counter typical and persistent misconceptions and enable visitors to shift from the naive knowledge of the “novice” to the more sophisticated under- standing of the science “expert.” The study revealed that hands-on exhibits with carefully worded labels can, indeed, alter naive notions and open the door to new understanding. INTRODUCTION 0 “Without air pressure, things would not fall.” 0 “It is summer when the Earth is closer to the Sun.” 0 “Moving air has more pressure than still air.” 0 “The rotation of the Earth creates gravity.” These statements were made by visitors to The Franklin Institute Science Museum during the course of the Naive Knowledge Study. All represent widely shared misconceptions. Long before receiving formal science instruction, people develop their own ideas about how the world works. These intuitive or “naive” notions are not indicators of developmental stages; they are held by adults as well Minda Borun is Director of Education at The Franklin Institute Science Museum. She also serves as Chair of the Committee on Audience Research and Evaluation of the American Association of Museums. Christine Massey is Assistant Profes- sor of Psychology at Swarthmore College and codirector of PENNlincs at the Institute for Research in Cognitive Science at the University of Pennsylvania. Tiiu Lutter was research assistant on the Naive Knowledge Study. She is currently a project specialist for the PENNlincs program at the University of Pennsylvania. 201

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Page 1: Naive Knowledge and the Design of Science Museum Exhibits

36/3 1993

Naive Knowledge and the Design of

Science Museum Exhibits MINDA BORUN, CHRISTINE MASSEY, AND TIIU LUlTER

ABSTRACT

The Naive Knowledge Study at the Franklin Institute Science Museum in Phila- delphia, Pennsylvania, took place over a three-and-one-half-year period ending in April 1992. It was both a research and application project to uncover widespread misconceptions about the concept of gravity held by museum visitors and to test the efficacy of hands-on exhibits in altering these naive notions. Exhibits were designed to counter typical and persistent misconceptions and enable visitors to shift from the naive knowledge of the “novice” to the more sophisticated under- standing of the science “expert.” The study revealed that hands-on exhibits with carefully worded labels can, indeed, alter naive notions and open the door to new understanding.

INTRODUCTION

0 “Without air pressure, things would not fall.” 0 “It is summer when the Earth is closer to the Sun.” 0 “Moving air has more pressure than still air.” 0 “The rotation of the Earth creates gravity.”

These statements were made by visitors to The Franklin Institute Science Museum during the course of the Naive Knowledge Study. All represent widely shared misconceptions. Long before receiving formal science instruction, people develop their own ideas about how the world works. These intuitive or “naive” notions are not indicators of developmental stages; they are held by adults as well

Minda Borun is Director of Education at The Franklin Institute Science Museum. She also serves as Chair of the Committee on Audience Research and Evaluation of the American Association of Museums. Christine Massey is Assistant Profes- sor of Psychology at Swarthmore College and codirector of PENNlincs at the Institute for Research in Cognitive Science at the University of Pennsylvania. Tiiu Lutter was research assistant on the Naive Knowledge Study. She is currently a project specialist for the PENNlincs program at the University of Pennsylvania.

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as children. Studies of science students from elementary and mid- dle schoollY2 through high school and indicate that stu- dents enter the classroom with preconceived notions about phe- nomena, notions that tend to persist despite instruction. Even stu- dents who give sophisticated answers to test questions often do not apply what they learn to their experiences outside the classroom.

Research on naive notions is changing our view of education. Learning is increasingly seen as an active process in which people select from, transform, and elaborate information to extend or re- vise existing cognitive structures. Learning is thus a shift from naive or novice to expert cognitive structures in a particular field or domain-a shift toward increasingly powerful explanations that ap- ply to a wider set of Teaching, then, is not simply a matter of conveying a correct understanding where there was no understanding before; rather, it must involve a process of concep- tual change from a less-sophisticated to a more-sophisticated con- ceptual organization.’

Even a well-defined, clearly-presented concept cannot be con- veyed if the novice’s conceptual structure is not prepared to accept it. The outcome will be either a failure to learn or a distortion of information to fit the novice’s model. This view of learning as constructive has important implications for teaching in both schools and museums.

Cognitive psychologists and science educators have studied what have been called “naive notions,” “alternative frame- works,” “schemata,” “preconceptions,” and “misconceptions.” These notions are common-sense views, widely shared by people of all ages. Many science educators have observed persistent mis- conceptions, particularly in the fields of physics and mathematics, and there have been attempts to rectify them. lo Researchers report success with several approaches to cognitive restructuring: con- cept maps,’ 1,12,13 Socratic dial~gue,’~ and “ideologic confronta- tion and conflict resolution.” ’’ However, few researchers have considered these issues in the context of science museums, nor have they explored the power of interactive exhibits to confront and alter naive notions. Elsa Feher’s work at the Reuben H. Fleet Science Center on children’s concepts of light and vision indicates that the museum is an effective laboratory for investigating how people learn and confirms that research on common misconcep- tions can lead to the creation of more effective exhibits that can help restructure visitors’ ideas. l6

The science museum’s powerful combination of hands-on exhib- its and explanatory text can produce the “aha” or breakthrough

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perception that opens people to new understanding^.'^ But all too often, exhibits illustrate or “embody” science principles rather than “explain.” Principles are embedded in the workings of the exhibits or demonstrated symbolically. For expert viewers, these devices are clever analogues for processes in nature, often delight- ful in their elegance. Unfortunately, the significance of the repre- sentation is lost on the novice visitor, who must base understand- ing on a label filled with technical terminology.

An approach that parallels recent work in classroom settings begins with front-end evaluation to determine visitors’ levels of understanding and possible misconceptions. Then prototype exhib- its can be built, evaluated, and revised. The result is exhibits that create a conceptual bridge from novice to expert explanation.

THE NAIVE KNOWLEDGE STUDY-AN OVERVIEW

The purpose of the Naive Knowledge Study was to investigate visitors’ misconceptions about gravity and to test the ability of hands-on museum exhibits to confront and alter such basic misun- derstandings. This project was part exploratory and descriptive and part experimental. It demonstrates the importance of basing exhibit design on careful front-end and formative evaluation. The study consisted of a number of phases.

Phase I. Exploratory Study-An exploratory investigation was undertaken to determine the focus of the study. Data collection began with a series of open-ended interviews to identify those sci- ence topics treated by exhibits in the museum that are associated with widespread misconceptions. Interviews were conducted in four exhibit halls: Astronomy, Mechanics, Electricity and Elec- tronics, and Aviation. The interviews dealt with five topics: the reason for the seasons, gravity, mechanical advantage, magnetic polarity, and Bernoulli’s principle. It was decided to use the sub- ject of gravity as a focus for our attempt to understand how naive notions are formed, integrated, and changed.

Pilot interviews to elicit visitors’ naive notions about gravity were conducted at the “Gravity Tower” and “Gravity Cone” ex- hibits in the halls of Mechanics and Astronomy, respectively. In- terviews revealed what appeared to be a recurrent and widespread set of misconceptions about the cause and effects of gravity. Since gravity is a confusing topic and even experts disagree about its cause and nature, it is not surprising to find naive notions about gravity. It is important to remember that naive notions are com-

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“ G r a v i t y Tower’ ’- Visitors watch in fasci- na t ion a s a marb le , pumped up to the top of a jo-foot column, falls on to a curved s tee l plate, and bounces in a series o f descending arcs. When asked why the ball eventually falls into the hole at the cen- ter of the dish, some say there must be a magnet below the dish. (Photo by Steven Goldblatt.)

mon-sense explanations held by people who are intelligent enough to have thought about the subject. They may be novices in physics, but they are certainly not naive people! What is interesting is the consistency and frequency of the misconceptions. Visitors’ naive ideas about gravity encompass a large part of the physical uni- verse, including air pressure, planetary orbits, the rotation of the Earth, magnetism, and the attraction of the Sun. Analysis of these interviews led to the development of a questionnaire protocol for an initial baseline sample.

Phase 2. Initial Baseline Sample-Interviews were conducted with a sample of 122 subjects, balanced for sex and stratified for the age groups 9-11, 12-14, 15-18, and 19+. Respondents were selected from people who came to the museum’s Astronomy ex- hibit and used the “Gravity Cone’’ device. Interviews were vid- eotaped to provide a permanent record for review and evaluation. Visitors were asked if they would be willing to answer some ques-

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“Gravity Cone’l-The site of our baseline in- terviews, which begin w i t h t h e q u e s t i o n : “Why does the ball fall into the hole?” Most visitors respond: “Be- cause of gravity.” The next question: “What’s gravity?” elicits a vari- ety of interesting and unexpected responses. (Photo by Steven Gold- blatt.)

tions to “help us find out how people like you understand the exhibit in order to help us make better exhibits.” They were told that “we are not testing you, but testing our exhibits.” A hand-held microphone was used to record the audio portion of the early in- terviews. This was later replaced by a tiny wireless clip-on micro- phone. The video camera was mounted on a tripod nearby. We explained to respondents that the tapes were being made for later analysis of the interviews.

The initial interview instrument consisted of eight questions based on those used in the pilot study. (For typical answers, see the section “Visitors’ Ideas About Gravity.”) The presence of misconceptions was scored quantitatively on the basis of responses to one or two questions for each naive concept.

Phase 3 . In-depth Baseline Study-As the project developed, the interview format evolved, increasing in both sophistication and length, with the presence of misconceptions scored across the en- tire interview (see Appendix: Final Baseline Protocol). The order of presentation of major subsections was randomized.

Questions did not always have a “right” answer. The attempt to map the extent and nature of misconceptions sometimes required that a naive notion be temporarily accepted for exploration. To

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make the questions easily understood by naive subjects, we used visitors’ own terms or language rather than the traditional language of the physicist or physics educator. We found this necessary to create a bridge to visitors’ naive notions and effectively elicit de- tailed responses.

As the variety and scope of misconceptions became clearer, additional questions and follow-up probes for specific responses were standardized. Respondents were asked questions that tested for the presence of different aspects of the identified misconcep- tions and were encouraged to say why they offered particular re- sponses. Further, questions related to mass were also included to give us a better estimate of the frequency of misconceptions rela- tive to “expert” views of gravity. Quantitative analysis, while in- formative for overall trends, was supplemented by qualitative anal- ysis of the complexity of visitors’ conceptions.

Since naive notions are common-sense interpretations that are widely shared by adults as well as children, nonscientist readers can expect to hold some of the views about gravity that will be discussed here. It will be helpful to understand that gravity is an attraction between objects which depends on their mass and the distance between them. The bigger the masses, the greater the attraction; the larger the distance between the objects, the smaller the attraction.

The interviews lasted an average of twenty minutes. Interviews were videotaped and then transcribed verbatim. Transcribed inter- views were checked and then coded separately by two researchers. (A detailed coding handbook was developed for the project.) Dis- agreements were resolved by blind coding of the entire interview by the principal investigator.

Subjects for the in-depth baseline study were a stratified random sample of 88 visitors, balanced for sex and stratified for ages 9-1 1, 12-14, 15-18, and 19+. Respondents were selected from visitors who had used the “Gravity Cone’’ device.

The new baseline replaced earlier data and provided a far more detailed view of the cognitive structure of visitors’ naive notions concerning gravity and related concepts. Data in the tables shown here are drawn from the results of the final baseline interview and replace preliminary findings (published elsewhere).

VISITORS’ IDEAS ABOUT GRAVITY

The five categories listed below, or combinations of them, capture a substantial portion of the gravity misconceptions we have iden-

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Table 1 . The misconceptions. Visitor Conception % of Visitors

Air Rotation Orbit Magnetism Sun

51 51 45 41 10

tified. Most subjects were found to hold more than one of these naive notions. Only 36% of the group showed any understanding that gravity is related to mass, and only 15% gave an explanation with no misconceptions.

Visitors were scored in as many categories as applied to their complete interview. The most prevalent misconceptions involve air and rotation and are each found in 51% of the interviews. Con- ceptions relating to planetary orbits and magnetism are also com- mon, with 45% and 41%, respectively. Finally, the idea that all gravity comes from the Sun is expressed by 10% of the sample (Table 1).

While not always present in identical form, there is much con- sistency in the identification of these factors as causes or necessary conditions for gravity. 0 Air: This category contains the idea that gravity is caused by air or air pressure, or that air is necessary for gravity to work. Sub- jects frequently distinguish between air and atmosphere and may attribute gravity to either one.

“Gravity is made of air.” “Gravity is the layer of air mass . . . 14.3 pounds of air per square inch.” “Without air pressure, things would not fall.” “Air pressure, which causes gravity, holds the planets in orbit and makes the

“. . . the atmosphere makes gravity, but [you] have to have [our] air.” tides. ”

0 Rotation: These misconceptions include the idea that gravity is generated by the Earth’s rotation and/or that anything that rotates has gravity. Another idea, shared by quite a few people who oth- erwise explain gravity correctly, is that gravity is helped or in- creased by rotation.

“[If the Earth weren’t rotating] there’d be no gravity because rotation is the

“[If the Earth weren’t spinning] we’d fly off into space.” “I’m not sure what causes gravity, but we wouldn’t have it to the same extent

causal part of the force.”

without rotation.”

0 Orbit: These notions have to do with the idea that gravity is the result of the orbit or position of planets in our solar system or of a

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universal balance such that disturbing or moving any part of the solar system would cause the whole thing to collapse.

“If there was no gravity, everything would lose its delicate balance; and we’d

“Earth’s gravity will operate [only] as long as the Earth is in orbit.” “[No gravity on other planets because] Earth is just right, and the other planets

0 Magnetism: This is the belief that gravity is generated by mag- netism or that gravity and magnetism are the same thing or have the same cause.

“[Gravity is] a magnetic field between the North and South Poles. . . . A

“A lot of proofs about gravity say we have magnetic force, so I’d say there has

go in toward the Sun.”

are too far or too close.”

magnetic field causes gravity.”

to be some sort of interplay. . . . It would be causal.”

0 Sun: All gravity is seen to come from the Sun. “Earth’s gravity is caused by the pull against the Sun.”

The Rationale for Misconceptions-Naive notions are not idio- syncratic or opportunistic responses to interview questions; they are widely shared, persistent, common-sense views. Sometimes these notions are based on a shared error in reasoning, sometimes on misinformation. For example, a frequent explanation for the air misconception is that astronauts float in space; they are floating because there is no air in space, so without air things must float.

The rotation misconception is often based on a confusion in frame of reference. People refer to a rotating amusement-park ride that thrusts people against the inner walls as it spins. They are actually being thrown outward from the center and held against the inside wall. This is confused with the idea that gravity holds things onto the Earth’s surface. Thus spinning is equated with gravity. The confusion is amplified by the fact that the name of this type of ride often involves a reference to gravity (e.g., “Gravitron”).

Cognitive Structures-Variations among our respondents were found not only in the content of their misconceptions, but also in the ways in which subjects fit various kinds of information to- gether. Sometimes the naive conception was a well-thought-out, coherent view, based on logically-related ideas; but more often the ideas expressed were not well developed and were poorly inte- grated. Often responses to questions were not supported by later comments or answers to other questions. What emerged was a confused patchwork of bits and pieces that did not fit together and contained internal contradictions.

In-depth interviews and careful qualitative analysis were neces-

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Table 2 . Conceptions of gravity by age group. % of Total % of Visitors with

Age Group Misconceptions Expert Explanations*t

9-1 1 12-14 15-18 19 +

28 29 22 21

* “Expert’’ means having no misconceptions. f The difference between total percent expert answers shown here and cited in text is due to rounding.

sary in order to understand people’s logic and explanations. Sub- jects sometimes used principles other than cause-and-effect rela- tionships to associate variables. Some explanations were teleolog- ical: if something is needed, it will come to be. We need gravity to keep us from flying off the spinning Earth, so spinning makes grav- ity! Also common is a view that the world and everything in it was created in a delicate balance, and nothing can be changed without endangering the whole. Such explanations may account for the residual population that did not learn from the prototype exhibits described here, but further research is needed to verify this view.

Within a Newtonian framework, there is the view that motion must derive from motion. Thus gravity, which pulls things in, must be generated by a motion such as the spinning of the Earth. Sim- ilarly, motion must act through a medium. Hence, gravity needs air to make things fall. People who held these views did modify them when exposed to our prototypes.

A common misconception about misconceptions is that they are held by children and replaced through formal instruction. Most previous research on naive notions is based on studies of students in classrooms. ’-’ However, our findings indicate that naive notions are widespread among adults. When we look at the incidence of misconceptions by age group, there is no correlation (x2 = 1.32, p < .73). However, when we consider the number of individuals who gave accurate responses, there is a significant trend toward an increase with age (x2 = 11.70, p < .009). Apparently, while learn- ing expert science information increases with age, misconceptions are also formed and maintained over time (Table 2).

These data give us a baseline picture of the widespread miscon- ceptions about gravity with which people enter the museum.

THE PROTOTYPES

Once the misconceptions about gravity had been identified, the next step was to test the efficacy of interactive exhibits in altering

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naive notions. Exhibit prototypes were developed to address the two most frequent misconceptions: air and rotation. The develop- ment process involved formative evaluation and modification of the device and label copy.

The Air Prototype-An exhibit was constructed to confront the naive notion that air is the cause of, or a necessary condition for, gravity. The device allowed people to experiment with a ball falling in a tube with and without air to see that, in either case, gravity would cause the ball to fall. A four-foot glass tube was attached to a vacuum pump. A ping-pong ball inside the tube fell from one end to the other as the tube was rotated by the visitor. The air could be pumped out and the tube again rotated (a recalibrated gauge fell to zero to indicate the absence of air); visitors observed that the ball did not float-it fell. The accompanying label explained that grav- ity has to do with the attraction of masses and that air is not necessary for it to work. Both the device and explanatory label underwent formative evaluation until people were able to use the device correctly and understand the label.

We tested a label with four different headings to see whether small differences in wording would affect visitors’ perceptions.

1. GRAVITY DOES NOT DEPEND ON AIR 2. GRAVITY IS A PULL BETWEEN TWO OBJECTS 3 . WHAT IS GRAVITY?

Four samples, each consisting of 25 cued visitors, nine years of age or older, were asked to read the label with one of the above headings and to try the device. They were then asked questions from the interview protocol.

The most significant result was the negative effect of the first label. In response to “What causes gravity?” 29% of respondents said “Air pressure” (in comparison to 5%, 0%, 0% for labels 2, 3, and 4, respectively). When asked, “Does gravity need air to work?” 38% of the subjects who read the first label incorrectly answered “Yes” (in comparison to 23%, 4%, and 0%, respec- tively). The impact of the word “not” seemed lost on readers, and the label succeeded in reinforcing the association of gravity and air!

The implications of this experiment are that (1) we cannot simply tell people a naive idea is not so, (2) negative statements are easily misread or misinterpreted, and (3) formative evaluation of labels is necessary to find out if they are effective in explaining an exhibit.

The label headed “GRAVITY MAKES OBJECTS FALL” was associ- ated with the lowest frequency of air misconceptions. This heading was used on the label in the prototype tests described here.

4. GRAVITY MAKES OBJECTS FALL

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Air Prototype-More than half of the visitors interviewed, from chil- dren to adults, thought that gravity needs air to work. Built to demon- strate that a ball will fall in a tube with or without air, this exhibit was very successful in dispelling the misconception that air is necessary f o r things to fall. (Photo by Steven Goldblatt.)

Air Prototype Results-A sample of 72 subjects, balanced for gender, in the four age groups, was interviewed. Cued visitors, who were asked to try the exhibit and read the accompanying explanatory text, were asked the same questions as those in the baseline sample. Their responses were compared to baseline data collected with a separate sample of visitors. The most dramatic, statistically-significant result of the air prototype is shown by re- sponses to the question about what happens to an object in a vac- uum. Only 13% expected the ball to float (compared to 29% in the baseline), a 55% decrease from the baseline level of 29% in the presence of this misconception (x2 = 4.86, p < .05). These re- sponses are typical:

“I would expect that it wouldn’t fall at all, it would just float there. . . . If you watched when they went on the Moon, they were floating in space. It sur- prised me because I think of something without air as floating . . .”

“The ball does the same thing [with or without air], goes right to the bottom.” “If you look at that. . . , gravity doesn’t need air.’’

Using the prototype to demonstrate that the ball behaves in essentially the same way with or without air in the tube was a

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convincing way of altering the air misconception. This finding has important implications for science teaching. It indicates both the efficacy of uncovering and directly addressing naive notions and also demonstrates the instructional power of a hands-on exhibit in an informal setting.

When visitors were questioned more generally about the rela- tionship between gravity and air, the results were only slightly less dramatic. Whereas 43% of the baseline sample predicted that grav- ity could not operate without air, only 23% of the post-prototype group said this-a 47% improvement (x2 = 5.96, p < .02).

Finally, although the purpose of the prototype was to alter a misconception, not to teach what gravity is, we did observe an increase in the frequency of answers indicating an understanding of the relationship between gravity and mass. The text on the exhibit explicitly addressed this relationship. There was a significant in- crease from baseline frequency of 36% to post-prototype, in which 57% of the respondents saw gravity as related to mass-a 58% increase (x2 = 5.96, p < .02). Thus, these data support the hy- pothesis that once their misconceptions have been confronted, people are open to learning new scientific information.

In response to a direct question about the purpose of the exhibit, 82% answered that it was designed to show that gravity does not need air to operate or that objects will fall in a vacuum. This result is a noteworthy transfer from a newly-acquired understanding of the prototype to a more general understanding of gravity. More- over, some people state that this is not what they expected and that they now have a new understanding of gravity. Movement in the direction of the novice/expert shift seems to occur (Table 3, page 215).

The Rotation Prototype-The second most frequent misconcep- tion about gravity is that it is generated by the Earth’s rotation. Here, a misconception-held by 45% of our baseline sample-is the notion that spinning pulls things in. The accepted scientific view is that a rotating object tends to push objects in contact with it away, not toward it. The purpose of the prototype was to dem- onstrate that the Earth’s rotation cannot account for the tendency of the Earth’s gravity to pull objects toward its core.

To demonstrate that spinning pushes things out was a straight- forward task. However, to show that the spinning of the Earth also tends to push things out and that gravity pulls things in, we had to work with a model rather than an actual demonstration. A model has limitations: (1) its relation to the real thing can be misunder- stood, and (2) it can be disregarded or not believed, because “it is

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only a model.” It proved to be much more difficult to develop a prototype to successfully confront the rotation misconception. We built and tested four versions before we found one that worked.

The purpose of the prototype was to demonstrate that rotation cannot account for the tendency of Earth’s gravity to pull objects toward its core, since a rotating object tends to push objects in contact with it away, not toward it. (The tangential direction of motion was intentionally left vague to simplify the explanation and emphasize the distinction between “toward” and “away.”)

The rotation prototype consisted of two parts. On the left was an umbrella-like structure, with two poles or arms attached at the top and a small figure at the free end of each arm. The umbrella was rotated by turning a crank. The arms moved out as the device rotated inside a transparent sphere, showing that spinning moves things outward. To the right of the “umbrella” was a globe with three small figures attached around the equator. Two switches, labeled “SPIN” and “GRAVITY” visually separated the two con- cepts; each switch could be turned on or off. When spin was “ON” and gravity “OFF,” the figures flew off the globe and dangled on the end of thin filaments. When “GRAVITY” was turned back on, they were pulled back to the globe. The main label read:

SEPARATE AND UNEQUAL FORCES If the Earth stopped spinning, gravity would still hold us down.

Can you prove it? (Use the ON/OFF switches)

As in the case of the air prototype, we experimented with the exhibit label. Once we had achieved a necessary balance between brevity and informativeness, none of our alterations contributed to a significant reduction in the frequency of the misconception. The language was reader-appropriate, the tone was consistent and en- gaging, the most vital concepts had been highlighted. Subjects

Rotation Prototype- More than half of the v i s i tors in terv iewed t h o u g h t g r a v i t y i s caused by the Earth’s rotation. This exhibit demonstrates that spin- ning flings things out (not in) and that we would still have gravity if the Earth were not spinning. (Pho to by Steven Goldblatt.)

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were asked to read all of the text, and generally did so. Yet, when asked, “If the Earth stopped spinning, would there still be grav- ity?” roughly a third of the respondents said “No.”

For one version, the label read simply, “Spinning does not cre- ate gravity,” but visitors only remembered that the two concepts had been associated. Again, the use of “not” reinforced the mis- conception. We needed to make a more fundamental change. We had to alter the relationships among user, label, and device.

Most labels act as instructors, placing visitors in a passive in- formation-receiving role. This approach is effective for people who learn well from reading but fails with other learning styles. As long as the label was written didactically, device and label were sequen- tial, not interdependent. We needed a label that sent the visitor back to the device to test the information, then back to the label to interpret the experience, which our last main label accomplished.

Rotation-Prototype Results-A sample of 48 subjects, stratified for age and sex, used the prototype. Subjects read the labels and operated the exhibit and then answered questions. There was a dramatic decrease of 76% in the concrete misconception. Only 1 1 % of our sample thought that spinning pulls things in (compared to 45% in the baseline sample) (x2 = 13.66, p < .001).

A follow-up question explored whether visitors could transfer this information beyond the prototype by asking if we would still have gravity if the Earth were not spinning. Again, there was some- what less improvement in transfer from the specific case to the general. Whereas 55% of the baseline sample predicted that we would not have gravity if the Earth were not spinning, 25% of the post-prototype group said this-a 55% improvement (x2 = 9.78, p < .01). The exhibit text explicitly states, “If the Earth stopped spinning, gravity would still hold us down.” However, including a concept in the text does not at all ensure that it will be understood.

Once again, we looked at the number of people who associated gravity and mass after using the prototype and compared this to the baseline sample. Here too, we saw improvement-in this case, an increase from 36% in the baseline to 52% after using the proto- type-a 44% increase (x2 = 4.20, p < .05).

Such improvement is surprising, since only one line in a second- ary label addressed the concept of mass. Apparently, removing the naive notion opened the door to acquiring accurate information. In the words of one visitor:

“I used to think gravity was somehow related to the Earth’s rotation, but I see that it’s not. So now I need a new theory.”

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Table 3 . Comparison of baseline and post-prototype conceptions.

Air Rotation Visitor Conception Baseline Prototype Prototype

Without air a ball will float.* 29 13 Gravity needs air to work.* 43 23

If it were not spinning, the Earth would not have gravity.* 55 25

Gravity is related to mass. 36 57 52

Spinning pulls things in.* 45 1 1

* Indicates misconception.

DISCUSSION

With both the air and the rotation prototypes, the goal was to explain what gravity is nor-not what gravity is. Our attempt to alter specific misconceptions through interactive exhibits seems to have been successful. Further, visitors appeared to enjoy having their misconceptions addressed. It’s more interesting to learn that you’ve had the wrong idea about something than to simply encoun- ter a set of abstract facts.

We make no claims for the longevity of the learning shown here. Like any other situation in which new information is acquired, there could be a tendency to revert to the naive notion. The new information would have to be reinforced to really take hold.

One of the unanticipated problems we have encountered is the reluctance of experts to accept the existence and prevalence of naive notions. It has been difficult to explain that people really believe that if the Earth were not spinning, gravity would cease, and we would fall off into space! Those with a traditional approach to physics instruction seem to persist in thinking that what’s needed is an exhibit that demonstrates what gravity is (i.e., a Cav- endish experiment). Our research, on the other hand, shows that people are not able to understand what gravity is until they see what gravity is not.

Exhibit design as we have described it here is not intended as a universal model. The gravity prototypes were constructed to re- fute particular naive notions. It is not desirable or feasible to design all exhibits to alter misconceptions. However, the results of this study do underline the importance of beginning exhibit design with an awareness of widespread misconceptions that may interfere with learning. If exhibit developers do not take such misconcep- tions into account, visitors are likely to perceive exhibits through a filter of preexisting naive notions and leave the museum with their misconceptions intact or even reinforced.

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Through front-end evaluation, developers can gain a sense of how novice visitors “understand” phenomena. The novice view should then be compared to the expert view or desired final state. If there is no gap between the novice and expert views, a conven- tional teaching exhibit can be used. If there is a very large gap, it is probably advisable to rethink instructional goals. If there is some correspondence but there are also crucial areas of disagreement, it is important to address some of these problem areas in the exhibit and to build explicit connections between the novices’ current approach and more sophisticated ways of looking at the topic.

The educational efficacy of a science exhibit depends on its ability to clearly demonstrate the scientifically acceptable (expert) explanation. If misconceptions are present, visitors need to see the error or limits of their naive ideas. If we know people’s precon- ceptions and explicitly address them in exhibit design, we may hope to move toward the cognitive restructuring needed for sci- ence learning.

Our efforts indicate that hands-on exhibits, developed on the basis of an understanding of naive notions, can be effective in altering the misconceptions. The findings indicate both the efficacy of uncovering and directly addressing naive notions and the in- structional power of hands-on exhibits in an informal setting.

Uncovering naive notions complicates the task of teaching sci- ence. The new techniques required to restructure misconceptions are more demanding than didactic presentation. But the rewards are worth the effort. Instead of encouraging rote memorization of science language, this approach can help people arrive at a more powerful understanding of the world around them.

Science museums face a difficult challenge. They attempt to teach expert ways of understanding science to learners whose knowledge structures are widely varied. To succeed, museums must come to know their audience as well as they know their science. With tools such as front-end evaluation and a grasp of the naive/expert model of learning, this task can be accomplished.

ACKNOWLEDGMENT

This project was supported by grant #MDR-875 13% from the National Science Foundation. Any opinions, findings, conclusions, or recommendations expressed herein are those of the authors and do not necessarily reflect the views of the National Science Foundation.

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APPENDIX: FINAL BASELINE PROTOCOL

Beginning Questions* I . What does this show? What makes the ball go down into the hole? 2. What is gravity? 3 . Does gravity push from above or pull from below? 4 . Is there gravity on the Moon? Why? 5 . Is there gravity in outer space? Why? 6. Is there gravity on other planets? How can you tell? 7. Is there gravity on the Sun? Why? Other stars? * Ask questions at “Gravity Cone.” Let exhibit experience elicit first responses. Rotation Questions (A) A. l Suppose you were out in space holding onto the outside of a space station. All

of a sudden the space station starts to spin. What would happen to you? ( I f l y 08, fall, orfloat offl: Why? (Nothing. I would just spin with it. OR I would be stuck or pulled to the side):

(Still stuck to station): Why? (Gravity): What does spinning have to do with gravity?

What would happen if you let go?

A.2 What would happen if you were inside the spinning space station? A.3 What about here on Earth, does the spinning of the Earth pull objects toward

A.4 What about the people and things in this room-does the spinning of the

A S Why aren’t we flung out into space? A.6 Would there still be gravity if the Earth were not spinning? A.7 Does gravity need spinning of some kind to work?

the surface or push them away from it? Why?

Earth pull us toward the ground or push us away from it?

(ZfS says no, ask all of the following:) a. If the Earth had never been spinning, would there still be gravity? b. If the Earth stopped spinning, what would happen to us? c. Does any spinning object cause gravity? d. Does anything besides spinning (of Earth) cause gravity? e. If the Earth were to spin faster, would it have an effect on gravity?

Air Questions (B) B.1 Does gravity need air to work? Why?

(Yes): Will any kind of air work or must it be Earth’s atmosphere? Why? (No): Is any sort of atmosphere essential for gravity? Why?

B.2 If I dropped a ball from the roof, as it is falling does it fall at the same speed or does it get slower or faster?

B.3 If I had a ball sealed in a tube and the tube had no air in it, and I turned the tube on its end, with the ball at the top, what would happen to the ball?

(If S deliberates for more than a “minute” without an answer, ask, “Will ball fall or float?”)

B.4 Would there still be gravity if the Earth had no air or atmosphere around it? Solar System Questions (C) C.1 If the Earth weren’t part of the solar system, if it were in space all by itself,

away from the Sun and other planets, would the Earth still have gravity? Why?

C.2 If the Earth were not in orbit around the Sun, would it still have gravity? Why?

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C.3 If the Earth and Neptune switched places, would Earth’s gravity change?

C.4 Is there a gravitational pull between the Earth and the Moon? How or why?

(Yes): If the Earth and the Moon were further apart from one another, would the gravity between them be different?

Magnetism Questions (D) 0 . 1 Does gravity depend on magnetism? How? 0 . 2 (Ask one or all of the following as appropriate to above)

a . So if you increased the Earth’s magnetism would gravity be affected? b. So if you put more magnets idon the Earth would gravity be affected? c . So if you increased the metal in the Earth’s core would gravity be affected?

(If S says they are sort of the same or related in any way): How are they similar or different?

0 . 4 (If S links gravity and magnetism): Does gravity pull on objects no matter

Mass Questions (E) E.1 Does something’s gravity depend on its size or weight?

0.3 So magnetism has nothing to do with gravity?

what they’re made of? What about magnetism?

(Yes, nor sure, equivocal, etc.): Why? If the Earth were bigger, would its gravity be different? (No): Why not? So if the Earth were bigger, its gravity would be the same?

E.2 Here is a picture of two lead balls. Is there any gravity between the big ball and the little ball?

Here’s another picture in which the same balls are further apart. Is the gravity between them the same as when they are closer together? Whywhy not?

Here’s another picture in which the same balls are further apart. Is there any gravity between them now?

(Yes): Are they pulling on each other? Whywhy not?

(No): Why Not?

Final Questions If you wanted to increase the Earth’s gravity, what would you do? What causes gravity? Can more than one thing cause gravity?

(Insert appropriate all-purpose probes here. if mass has not been mentioned previously, ask floating questions here. Use conversational statements as needed.) Floating Questions (If visitor spontaneously mentions mass at any time):

What is mass? If I have a Styrofoam ball and a lead ball of the same size, do they have mass? (Yes): Is it the same for both balls? Do they have gravity? (Yes): Is it the same for both balls or does one have more? Do they have their own gravity or are they getting it from somewhere else?

All-Purpose Probes ( X and Y stand for any two factors that have been cited as causal. If S says X and Yare related to gravity):

Can you have gravity without X? Can you have gravity without Y?

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If you have X but not Y will there still be gravity? If you have Y but not X will there still be gravity? Is X (Y) alone sufficient to cause gravity? How do X and Y (Z, etc.) work together to cause (influence, affect) gravity?

NOTES

1. Nussbaum, J. (1979). “Children’s Conceptions of the Earth as a Cosmic Body: A Cross-age Study.” Science Education 6311: 83-93.

2. Pines, L. A., and Novak, J. D. (1985). “The Interaction of Audio-Tutorial Instruction with Stu- dent Prior Knowledge: A Proposed Qualitative Case-Study Methodology.” Science Education 69/2: 2 13-228.

3. Clement, J. (1982). “Students’ Preconceptions in Introductory Mechanics.” American Journal of Physics 501 1.

4 . McCloskey, M.; Caramazza, A.; and Green, B. (1980). “Curvilinear Motion in the Absence of ExternaI Forces: Naive Beliefs About the Motion of Objects.” Science 210/5:1139-1141.

5. McDermott, L. C. (1984). “Research on Conceptual Understanding in Mechanics.” Physics To- day 371 24-32.

6. Gentner, D., and Stevens, A. (Eds.) (1983). Mental Models, Hillsdale, NJ: Erlbaum. 7. Carey, S. (1985). Conceptual Change in Childhood. Cambridge, MA: MIT Press. 8. Gardner, H. (1991). The Unschooled Mind, New York, NY: Basic Books. pp. 143-166. 9. Carey, S. (1986). Cognitive Science and Science Education:, American Psychologist 41/10: 1123-

1130. 10. Helm, H., and Novak, J. D. (1983). “Misconceptions in Science and Mathematics.” Proceedings

of the First International Seminar on Misconceptions in Science and Mathematics. Ithaca, NY: Cornell University Press. p. 12.

11. Cullen, J. F., Jr. (1983). “Don’t Lose Your Students, Use a Map.” In Helm and Novak, op. cit. 12. Novak, J. D. (1983). “Metalearning and Metaknowledge: Instruction As Strategies to Reduce

Misconceptions.” In Helm and Novak, op. cit. 13. Bar-Lavie, B., and Novak, J. D. (1983). “A Twelve-Year Study of Conceptual Development

Using Concept Mapping as an Evaluation Tool.” In Helm & Novak, op. cir. 14. Clement, J. (1987). “Overcoming Students’ Misconceptions in Physics: The Role of Anchoring

Intuitions and Analogical Validity.” Proceedings of the Second International Seminar on Misconcep- tions and Educational Strategies in Science and Mathematics. Ithaca, NY: Cornell University.

15. Nussbaum, I., and Novick, S. (1981). “Creating Cognitive Dissonance Between Students’ Pre- conceptions to Encourage Individual Cognitive Associations in a Group Cooperative Construction of a Scientific Model.” Paper presented at the annual convention of the American Educational Research Association, Los Angeles, April 1981.

16. Feher, E., and Rice, K. (1985). “Development of Scientific Concepts Through the Use of Inter- active Exhibits in a Museum.” Curator 28/1: 3546.

17. Feher, E., and Rice, K., op. cit. 18. Borun, Minda. (1989). “Naive Notions and the Design of Science Museum Exhibits.” Proceed-

19. Borun, Minda, and Massey, Christine. (1990). “Naive Theories Project-An Update.” Proceed- ings of the 1989 Visitor Studies Conference, Center for Social Design, Anniston, AL.

ings of the 1990 Visitor Srudies Conference, Center for Social Design, Anniston, AL.

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