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	" ON T.V., I SAW... WHY THERE ARE EARTHQUAKES "OR PICTURES FOR LEARNING SCIENCE

Jean-Charles ALLAIN

IUFM de Bourgogne

Dijon, France

1996

To elicit the title of this communication and the problematics taken on, I will start with a few sentences of a dialogue between 9 and 10-year-old pupils (Cours moyen, cycle III of French Elementary School).

"An earthquake, it is the earth that shakes and opens up when a volcano explodes". This is the way a ten-year-old child expresses himself at the beginning of a lesson on the subject and before any contribution from the teacher.

"I don't quite agree with D." retorts another student, "because he said that the earth shakes when there's a volcanic eruption, but that's not always true. Take San Francisco for example, there was an earthquake but no volcanic eruption !"

And the discussion goes on between the students.

"It's when two plates meet."

"I saw an earthquake on T.V. during the news. Buildings, and walls collapse."

"The highway was bent out of shape and there were cars underneath. There was also somebody filming during the earthquake and you could see the shaking."

"On T.V. they showed a house cut in half with a huge crack in the earth."

"They said on T.V. that a lot of people were hurt and killed when the road split or bent."

"I saw a report on T.V. that said that there was an enormous chasm in the middle of the Atlantic."

"I think that in the beginning everything was linked together, then after, there was an earthquake which made a fissure and everything separated".

These few lines of dialogue between pupils show us the strong attraction they have for volcanic and seismic phenomena plus the enormous impact television has on children. I was able to measure this impact (see chapter 3) with tests given to a group of pupils (8-10). On one hand, these tests helped me locate positive contributions already at work in the pupils' minds modifying their conceptions. On the other hand, they pointed out inaccuracies and mental confusions sometimes created by these pictures seen outside school, then.

A part of this research is on all sorts of pictures available on this subject as well as on the roles they can play in constructing knowledge (see chapter 2 & 3), obviously at a moderate level of complexity taking into account the referred groups.

In fact, in order to facilitate conceptualization, when teaching science more than any other field, we need to supply pupils with visual representations of the objects they need to know. When it concerns the field of teaching methods of science, one can wonder if we could not reverse the traditionally established relation between pictures and knowledge. For a long time pictures simply had an illustrative value to introduce a notion or to replace what had already been said.The new status that these pictures are gaining in the field of science (observation, abstraction, modelling) make one reconsider the didactic roles they could have in the construction of pupils' knowledge.

One of the hypotheses that we make is that pictures, by the modelling activities which they allow form an area for the pupils' minds, an area where they can challenge and control their own inner conceptions and finally a way to shake these ideas and to construct new ones at least for the notional field taken on.

1 INITIAL CONCEPTIONS OF EIGHT TO TEN YEAR OLD PUPILS

1.1 CONCEPTIONS ABOUT EARTHQUAKES

If the pupils' conceptions about volcanoes and eruptions are stereotyped and quite similar, it is another story if we ask these same pupils to talk about earthquakes and their causes. To the question asked "Why are there earthquakes ?" in one classroom, the answers gathered are incredibly diverse. However, despite numerous individual variations, constant categories appear in all the classes tested.

1) Earthquakes are caused by volcanic eruptions. Many pupils describe volcanoes as the cause of earthquakes (fig 1.1). They back up their explanations with different eruptive manifestations, lava emissions at high temperatures, explosions, and sometimes even the influence of underwater volcanoes (fig. 1.2).

2) Pupils talk about natural causes from within the earth.

-Internal heat (fig 1.3).

Fig. 1 - Some examples of initial conceptions on the causes of earthquakes (8 to 10-year-old pupils).

-Internal fire (fig 1.4) : a pupil proposes "earth is like a box that contains fire energy. When the energy is too strong, it makes the earth crack."

-Deep vibrations : "The core at the center of the earth moves and that's what makes earthquakes."

-Air in the earth (fig 1.5) : "Earth has currents of air, the air pushes forward and the earth shakes." One can only think of the famous "subterranean winds" by Aristotle.

-Propellant of magma : "There are earthquakes because the magma which is at the center of the earth has a kind of propellant which little by little destroys the earth with lava."

3) Atmospheric causes.

-Wind, rain, snow.

-Hot, cold : some pupils clearly establish a correlation between hot climates and earthquakes. Association between heat in warm countries and heat from the lava causes confusion.

-The ozone layer : this time the confusion comes from another planetary phenomenon, ecological consequences of a possible destruction of the ozone layer.

4) Local tectonic causes : cracks, fissures, faults, ravines.

5) Large scale tectonic causes : straight out, before any contribution from school, pupils talk about continental drifting, and even the plates, that is to say lateral movements. One pupil goes as far as drawing the California shift in relation to the rest of the American continent. Another one draws the India and Asia confrontation.

6) Formation of mountain ranges : "there are earthquakes in order to make room for other mountains. When the folds of the earth's crust moves they cause earthquakes".

7) An expanding earth : for one pupil, "the earth shakes because it is getting bigger". A theory refuted by many scientists but which still has followers ! Another one suggests a similar explanation "because earth dates back millions or billions of years." Same idea, only here we find the principle of the isostacy theory (one of the first known movements of the earth's crust was the one meter increase each year of Scandinavia.).

8) The rotation of the earth : "I think that a slight gap in the time of the earth's rotations can create an earthquake."

9) Human Causes : "There are earthquakes because people fight wars and drop bombs that explode in cities and countries". Strong influence of the news and surrounding environment , however confusion still exists. In fact, for this age group studied (8-10), only two students (out of 200) suggested human activity. With younger students, this proportion would be much higher (Deunff, 1990).

10) Extraterrestrial causes (fig 1.8) : "Another planet on collison course with earth. The earth quakes because fire balls head toward the earth. There are earthquakes because meteorites crash down." News can perhaps lead to this confusion. For several years the media has been stating that the disappearance of dinosaurs is due to the hypothesis of a meteorite disaster.

1.2 VARIED AND HETEROGENOUS CONCEPTIONS

The preceding inventory allowed us to note that pupils' ideas of these volcanic and sismic phenomena are numerous and heterogenous. This observation is a lot clearer for the causes of earthquakes than for volcanic phenomena. Even if one cannot notice, with the concepts taken on, a progression of the conceptions that would bring to mind the historic evolution of ideas, we can however find a similar situation to that of 18th or 19th century where numerous hypotheses appeared. Some were serious and backed up by long studies and measures (see the correlation between earthquakes and seasons), others, more whimsical (electric fire, cylones...) were quickly forgotten.

In our sample eight to ten-year-old students, almost systematically rely on natural causes (volcanoes, heat, fire, air) to explain these phenomena. Sometimes, they use other explanations (wind, rain, ozone), some even go as far as suggesting extraterrestrial causes (meteorites, stars, planets).

Progression of the child's thought within this age group studied is hard to notice. One can not clearly mark one kind of idea preceding another. Nevertheless, among most of the pupils, one can claim that the stage "volcanoes = cause of earthquakes" precedes that of "tectonic causes with continental drifting, then plates".

Among the ideas expressed by the pupils, a number of them are inaccurate, at least partially. This is the case, for example, in affirming that earthquakes are caused by volcanic eruptions. Some mental models analysed, even false must, for pupils at this age, constitute a temporarily effective explanatory system. In a statement by the children of the existence of a simple lineary causality : "volcanic eruption earthquake", there is an encouraging idea of a link between these two phenomena (badly expressed, of course) and the idea of underlying magma. Two ideas still not clear in their heads but which can be exploited later on in class (third year of secondary school).

Perhaps these conceptions about earthquakes, inaccurate as they are for many of them, do not represent large obstacles that oppose the construction of knowledge. Instead, one might consider them as a rather benign necessary stage for the pupil.

1.3 OBSTACLES, DIFFICULTIES, CONFUSIONS

The analysis of these conceptions reveals some obstacles of the epistemological nature and others simply of a didactic nature.

*Among the epistemological obstacles defined by Bachelard (1938) in the notional field that concerns us, one can call to mind fixism, that is to say a static vision of earth and an obstacle in the development of the concept of geological time. This obstacle did not really seem to cause a problem for the students observed here. Actually, a lot of them, starting at eight years old, easily envisage continental drifting to the earth's surface.

The analysis of the pupils work shows some examples of two other obstacles of the same nature : anthropomorphism and artificialism.

*Anthropomorphism : in this case, there is an abusive correspondance between the way nature and humans work. When these natural phenomena are concerned, pupils use expressions that show their feelings and human behavior : "A volcano spits out its lava. Fissures that suffers. Earth has discharges of air." In fact, at cycle III these anthropomorphic adherences are not very frequent. They are more frequent with younger pupils.

*Artificialism : humankind and their technology are known for giving an explanation to these phenomena. We encountered a case in this area : an eight-year-old pupil quotes "war" and "bombs" as being at the origin of earthquakes. Another one imagines "a propellant of magma". In that case, there is certainly an idea linked to factual knowledge with a reference to a mechanical model.

* In geology, the slowness of geological processes makes them unnoticable on a human scale, often causing difficulty. It might be the case here when it comes to representing the speed of drifting of the plates on each side of a rift, however, the suddenness of a seismic phenomenon tends to overshadow this problem.

* Deepness and inaccessibility : in fact, most of the tectonic phenomena happen under water and have been, until recently, unnoticed for centuries. That can be a problem for the mechanism of understanding, as shown by the student's surprise when they discover, with the help of pictures, the underwater eruptive phenomena !

* Proportion problems : how is a pupil able to link a local phenomenon to a more general cause and a global theory of earth ? The words that some pupils use express these problems. One of them uses the word "platform" instead of "plate", another confuses the Bay Bridge plates with those of the earth's crust.

Some confusions with the vocabulary and also with the implied conceptions : some of the pupils confuse internal heat, undoubtedly formed in their imagination from the heat of the lava with atmospheric heat. Some of them will go as far as deducing that earthquakes happen in warm climates. What we have here is a sort of analogical reasoning: children bring together two things belonging to different fields.

Their understanding of a lot of these concepts (plate, fault, lava, magma...), taking into account the young age of the pupils, does not correspond to the signification given by scientists. What we have here is more a question of "protoconcepts" according to the Woodfield expression (1992). Nevertheless, plates for them already seem to correspond to mobile entities and bits of the earth's crust. Some hesitate to place these plates at the surface of the earth and pin point them somewhat deeper : "There are earthquakes because plates move under oceans and continents."

2 ACTIVITIES ON PICTURES

2.1 DIVERSE SOURCES

Whenever a natural disaster occurs the news delivers the pictures to us right away. The phenomenon is amplified for several days if the country in question is America with its fabulous media coverage, newspapers and televised reports.

First, they highlight spectacular pictures depicting human incidences and material destruction, stressing the vulnerability of humankind and their constructions. However, sometimes pictures with explanatory value are added to these spectacular pictures. Pictures of faults (see -the San Andreas fault), diagrams, maps, cartoons : continental drifting, expansion or reduction of the rifts are also used to help in understanding the phenomena.

Not only are the pictures different by their social, informative and documentary uses (putting the accent on, either the descriptive and spectacular, or the explanatory), they are also different because of the languages they use. Some of them are very close to the reality surrounding the children, others go further away and take us into the invisible and abstract world to help us understand. On the other hand, they can also be still or animated pictures.

Three kinds of pictures can be retained :

- those that render visible what is not available through direct observation,

- those that show geological phenomena in motion which are normally unnoticeable on a human scale,

- pictures such as cross sections, graphics, diverse diagrams with a high explanatory value.

2.2 PICTURES FOR LEARNING

When we propose different activities based on pictures to the pupils, one can reconsider their role and give them diverse functions as part of the learning process.

* Didactic functions : Pictures allow an access to knowledge. These are the information transmitters.

* Cognitive functions : pictures used progressively in the classroom can effectively help modifiy the pupil's conceptions. Pictures can participate in the process of knowledge construction and act in the transformation of mental models. These are not only copies of what is real but models for learning.

* Epistemological functions : the picture is an "instrument one uses to elaborate, to structure, to manipulate knowledge" (Mottet, 1995). Some of these pictures have a very effective explanatory power beause they make hidden structures apparent and show the phenomena in action : the earth's crust in movement. Thanks to their high explanatory value they allow the pupil to progress in comprehending these complex phenomena. They can also accomplish an explanatory work ; their handling makes structuring of thought process visible.

These pictures are not immediate tools of knowledge. They only become so if appropriate didactic activities are organized. One must create situations in which the students actively manipulate these objects : choose, put in order, comment, complete the pictures, even draw them in order to describe or explain a phenomenon. It is quite clear that after exploring the thoughts of young children, one concludes that we must create situations that would facilitate the learning process : the pictures would not only be there to show illustrative information but they would also become an authentic help in the restructuring of knowledge.

3 ROLES OF PICTURES IN CHANGING THE PUPILS' CONCEPTIONS

3.1 MAINSTREAM TELEVISION CAN CREATE A FIRST "CRACKING" OF IDEAS

A large number of pupils in the tested classes reach a better level after having seen televisual pictures on the subject outside the classroom. A very clear relationship appears between television and the formation or transformation of the pupils conceptions for the problem taken on.

However, certain risks exist ; these exterior contributions from media can sometimes create an incorrect or blurred image. For example, a pupil confuses pictures of the plate in the San Francisco bridge seen on television with the plates of the earth's crust ! Another one, influenced by spectacular pictures of destruction (gas pipeline explosions, water canal leaks, fallen electrical lines, fires) caused by the last earthquake in Los Angeles, confuses the causes of earthquakes with the consequences. He talks about " electricity that causes fire" and "a fire energy that is too strong and that makes the earth crack." Some pupils talk about the movement of the plates but get mixed up in the formulation, "platform that moves" or situates the plates "under the earth's crust" or "under continents and oceans." Another one talks about the drifting of California in relation to the rest of the American continent but makes it drift south instead of north. When compared to the established idea of drifting fragments of the earth's crust, this is not a big mistake. Some of these mistakes could infuriate an expert on the subject, but we should take into consideration the pupils' age (the average age 8 to 10), and also remember the fact that these ideas were collected before any teaching of the subject.

And is school not there to organise pupil's knowledge ?

3.2 SEVERAL STRATEGIES

Not everyone benefited in the same way from the televisual pictures seen on this subject outside school. Some kept their former ideas, certainly because they have not understood the proposed explanations (they admit not understanding them), whereas others grasped a relatively satisfying level right away with a beginning of modification of their conceptions. Several "ways of thinking", several mental strategies appear :

- either the pupils do not take into account this new contribution perhaps too fleeting or hard to be understood at their level,

-or they couple their old ideas with the new ones (volcanism and plates),

-or they suddenly change their ideas and integrate the new ones : faults, fissures, continental drifting, even correct ideas of the shifting of plates at the earth's surface.

These scientific explanations, already present in the minds of pupils from eight to ten years old lead one to think that the medias have a strong impact. It seems not only to reinforce the dramatic and catastrophic aspect largely developed by T.V., but as well to supply them with the first elements of understanding. This experiment took place shortly after the San Francisco disaster in 1989 and the Los Angeles disaster in 1994, both of them widely covered by the media. It is therefore logical to think that these televisual contributions outside school have already permitted the creation of first mental models on the explanatory theory of these disasters or at least provoked the first destabilizing "cracks" in the mental models previously at work in these young pupils' minds. This "cracking" should facilitate the setting of a new explanatory model in the future.

3.3 EXAMPLE OF A PUPIL'S PROGRESSION IN UNDERSTANDING EARTHQUAKE CAUSES

Before any work on the subject (T1), Caroline, nine years old (fig.2), a "good student" according to the teacher, uses volcanoes to explain the causes of earthquakes. In T2, after having assimilated new contributions (analysis of documents), she radically changes her conceptions and envisions a shifting of plates (actually, in her mind, continent) : "Africa used to be linked to India. But India started to separate from Africa and linked itself to Asia. India's plate pushed Asia's plate and caused an earthquake and formed the Himalayas."

In T3, she draws a correct diagram (very simple, cross sectioned, with directions) which shows an intellectual progression and indicates the impact of the explanatory pictures used during the session. One month later (T4), she redoes the diagram that had been constructed in her group : the direction is good and the links are clear between the confronting of plates and formation of volcanoes, earthquakes and mountain ranges. Three months later (T5), her interpretation of the diagram is a sign of persistence of a good level : "There are underwater volcanoes in the ocean that separate the plates. One goes to one side the other goes to the other side. When moving to one side the plate meets another plate and creates an earthquake".

However, one must note, for this age group, the limits of the constructed model : oceanic expansion as the only cause of drifting is a partly incorrect conception from a scientific point of view.

Fig.2-Caroline's progression of answers to the question :

Can you explain why there are earthquakes ?

3.4 IMPORTANCE OF PICTURES WITH EXPLANATORY VALUE

Children are primarily stricken by the sensational pictures of the unknown, for example, underwater volcanoes. Granted, one can accuse the children of being attracted to the sensational. However, one can also notice that retained pictures bring information about how the bottom of the ocean is created : underwater effusive volcanism of the oceanic rifts. On the other hand, they are barely stricken by realistic pictures (for example, the destruction of buildings) perhaps it is because they are so familiar, rendered commonplace by external influences.

More than half of the pupils admitted that the pictures with explanatory value helped them : maps, cross sections, cartoons, and models facilitate comprehension of a mechanism. Certainly these pictures that we sometimes call "explanatory pictures" can have an explanatory value in a particular learning context. They supply elements of explanation. Most often they are simplified pictures and designs which facilitate conceptualisation of the problem taken on. Thanks to their simplification and varying degree of abstraction, they bring out the essential to be seen and understood of a complex phenomenon.

Nevertheless not all pictures are as effective in the construction of a given concept. Moving pictures seem to be more effective than still pictures in the process of modelling a reality whose movements are unnoticeable. It is very clear with an animated representation in a cross section of oceanic expansion in the medio-Atlantic ridge which appears in a cartoon shown. The cartoon proposes an analogy based on the rift to help understand movement of the bottom of the ocean. It compares the movement to that of a rolling sidewalk. It is not a snapshot of reality. It is a vision removed from reality, filtered, simplified, relying on a strong schematization. By using metaphors and analogies, one substitutes simple elements to a much more complex reality. With these kinds of pictures, young children can understand the upward motion of magma at the heart of an oceanic ridge and the spreading of these two lips. "We saw it separating, it was fascinating."

In constructing the diagrams, the children were helped also by the different televisual pictures. Spontaneously after watching bits of film the children had the idea to draw diagrams themselves. It is necessary to note the important stage of simplification and of abstraction reached by these pupils. Their diagrams are extremely basic but nevertheless very explicit and clear. In some of their propositions the idea of plate clearly appears.

4 CONCLUSION : LEARNING SCIENCE WITH PICTURES

Some descriptive pictures, because they are unusual, (like the bottom of the ocean) permit ten-year-old pupils to imagine the earth's movements at the heart of the ridges themselves. Other pictures, cartoons for example, help them grasp a general idea of the dynamics of the earth. Maps of the distribution of volcanoes in the world, those of earthquakes and plates limits, help the pupils situate local phenomena at a global scale, permitting access to a global explanatory theory. It appeared to us that pictures were even more useful at an explanatory stage than as a tool to describe the seismic and eruptive phenomena. Pictures are helpful in constructing concepts. For instance the sismogram picture allows the visualisation of waves and therefore allows one to understand that an earthquake is defined by vibratory manifestations which are propagated in the earth's crust ; a cross section of the earth's depths permits to visualise expansion or reduction phenomena and therefore to predict a movement. In this learning context an picture does not only have a neutral informative value, it also has a strong explanatory value in understanding these complex tectonic aspects.

Because they allow various activities and the development of diverse "pictures-situations", pictures are also a way of challenging knowledge and therefore a way of transforming it. It is unquestionable, at least for the subject taken on, that pictures have a role in organizing the structure of knowledge : they allow diverse manipulations and confrontations, activities on the links between language and pictures, use and production of pictures. The evolution of the pupil's drawings during the activities as well as the progression of their knowledge show the impact of pictures in improving conceptualization levels.

Pictures that permit children to discover and understand scientific phenomena gained a new function : they are no longer simple attractive illustrations. It has been shown that young pupils who didn't know the causes of earthquakes (due to their young age) were helped by the challenging effects of pictures in creating new mental models (sometimes with errors). They also help change the explanatory model when the pupils already have an idea on the subject.

These pictures become instruments of knowledge treatment, essential helpers when teaching these notions. They act in the "conceptual change" (Posner, 1982) to challenge most of the pupils' way of thinking and contribute in changing them and then restructuring them. A true cognitive absorbtion of these pictures.

In my opinion, teaching science today can no longer be done without taking into account the extraordinary potentialities of pictures, provided that they are integrated in a pertinent way in a didactic device. It is necessary to use the complementarity to represent reality. Not only do pictures expose a knowledge which can instigate an effective challenge in the learner's mind but they also have a privileged role in the evolution of concepts, and therefore in the process of the elaboration of knowledge.

5 BIBLIOGRAPHY

5.1 PICTURES AND TEACHING METHODS

ALLAIN, J.-Ch. (1994) L'évolution des conceptions d'élèves de huit-dix ans à propos des causes des tremblements de terre grâce à l'utilisation d'images. Mémoire de DEA. Paris VII.

ALLAIN, J.-Ch. & DINARD, G. (1994) Volcans, tremblements de terre - Figures, schémas et modèles - Des images pour schématiser et modéliser. In Actes du colloque Audiovisuel, formation initiale et formation continue des enseignants, 23-25/11/1992. Paris : Institut national de recherche pédagogique.

MOTTET, G. & al. (1994) Des images pour apprendre les sciences. In Actes du colloque Audiovisuel, formation initiale et formation continue des enseignants, 23-25/11/1992. Paris : Institut national de recherche pédagogique.

MOTTET, G., ALLAIN, J.-Ch., BOUTOT, B., MINGUEZ, R. (1995) Volcans, tremblements de terre - Images descriptives, images explicatives. Paris : Institut national de recherche pédagogique.

POSNER, G.-J. & al. (1982) Accomodation of a scientific conception : towards a theory of conceptual change. In Science Education, N°66, 211-227.

WOODFIELD, A. (1992) Un modèle à deux étapes de la formation des concepts. In Introduction aux sciences cognitives. Sous la direction de M. Andler. Paris : Gallimard, 273-290.

5.2 VOLCANOES AND EARTHQUAKES

BARDINTZEFF, J.-M. (1992) Volcanologie. Paris : Masson.

BARDINTZEFF, J.-M. (1993) Volcans. Paris : Armand Colin.

DEUNFF, J. & al. (1990) Contribution à la définition de modèles didactiques pour une approche de la géologie à l'école élémentaire et dans la formation des maîtres. Compte rendu de recherche. Paris : Ministère de l'Education Nationale/Direction des Ecoles.

GOHAU, G. (1987) Histoire de la géologie. Paris : La Découverte.

KRAFFT, M. (1991) Les feux de la Terre. Histoires de volcans. Paris : Gallimard.

NICOLAS, A. (1990) Les montagnes sous la mer. Orléans : Bureau de recherches géologiques et minières.

TAZIEFF, H. (1972, 1991) Volcans et dérive des continents. Paris : Presses Universitaires de France.

ANNEXE

Résumé : Jean-Charles ALLAIN

L'analyse des conceptions initiales d'élèves de huit-dix ans sur les causes des tremblements de terre met en évidence leur grande variété, les difficultés et les protoconcepts en construction. Pour ce champ notionnel particulier, l'impact des médias est très fort. Des activités sur des images choisies font évoluer ces conceptions et participent à la création de modèles persistants.