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Writing challenging science texts: pedagogical implications from research about students question generation Piedade Vaz-Rebelo pvaz@mat.uc.pt Faculty of Sciences and Technology of the University of Coimbra, Portugal J. Otero P. Fernandes J. Morgado ATEE 35th Annual Conference Budapest, 26 -30 August 2010

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The research a set of empirical studies have been developed addressing question generation when subjects process written information.

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Aims Analyse the influence of reading goals on question asking on scientific texts. Identify moderator variables, in particular, text and context features. Develop norms to write educational science texts.

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Justification Reading and understanding texts are competences that must be developed in the scope of the actual science curricula. There is evidence that texts and school science books have a prominent role on the teaching- learning process. Positive attitudes toward reading comprehension leads to positive attitudes toward the scientific themes presented.

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Conceptual framework When a subject reads a text the immediate goal consists in creating an internal representation of discourse appropriate for the attempted task. Building a situation model representation involves generating inferences that elaborate the text base. Obstacles may be found in this attempt.

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The model This work is based on the model that has been developed by Otero et al. Input Goal TEXT OBSTACLES MENTAL REPRESENTATION Question generation Information seeking questions (ISQ) may be asked to overcome obstacles (Ishiwa et al., 2008).

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Other variables moderator variables Input Goal TEXT OBSTACLES MENTAL REPRESENTATION Question generation Text characteristics

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General Methodology Students were provided with booklets that included texts and written instructions on the reading task. They were advised to write all questions that they may have on the passages in the space provided. The questions asked were classified into three categories, according to the taxonomy proposed by Ishiwa et al. (2008): association questions, explanation questions and prediction questions.

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Study I Reading goals The first study involved a sample of 100 12th grade students attending Portuguese schools. Materials Two paragraphs that described and explained physical phenomena that could be reproduced in a laboratory were used: Cartesian diver (143 words) Heating water by stirring (153 words) There were two different suggested reading goals: reading for understanding reading for experimenting

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Heating water by stirring The quickest and most natural way to heat water is to put a coffee pot of water over a fire. What perhaps most people dont know is that water can be heated in another more original way. This can be reproduced with the following experiment that illustrates the Equivalence Work-Heat Principle. We take a very heavy object suspended by a resistant wire. This wire must be rolled in a vertical pipe, connected to several blades which can rotate while bound to it. You put the blades and the pipe into a container with the water you want to heat. When the heavy object falls, the blades will rotate and the water will heat. The explanation of the phenomenon is as follows: the weight of the object falling from a certain height performs work: the object falls and makes the blades rotate thus acquiring kinetic energy. The blades, by rotating, perform work on the water, thus increasing its internal energy. This can be proved by measuring the temperature of the water.

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The Cartesian diver Submarines explore the depth of the oceans, both floating and diving to the oceans bed. To understand how they work, a toy invented by Descartes, the Cartesian Diver may be used. It can be made with a plastic pen cap and a piece of plasticine. The Cartesian Diver is put into a plastic bottle with water near to the top, so that it can float with the top of the cap outside of the water. We must be careful not to choose a cap with a hole and we must test, in a glass of water, the quantity of plasticine so that the Cartesian Diver can float. If we cork the bottle well, when we press the sides of it, the Cartesian Diver will dive to the bottom. To make it come up, we just have to release the pressure on the bottle. A physicist would explain that a body can float whenever its weight balances the buoyant force on it. As this is a force equal to the weight of the displaced fluid, it grows a little when we press both sides of the bottle. However, the Cartesian Divers weight increases too, because of the water that goes inside the pen cap. We can conclude from this that the Cartesian Diver only submerges when its weight supplants the buoyant force.

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Results

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-No significant effects were found for task condition for any of association, explanation or prediction questions. -However, number and type of questions did depend on passage: significantly more association questions were asked on the Heating passage than on the Cartesian diver passage, while the opposite was true for explanation questions.. -This fact points to differences in the characteristics of passages. Study I Results

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Why are the paragraphs processed differently by stydents? In order to examine the sources of differences between passages in a post-hoc analysis, both texts were examined with the computational tool Coh-metrix (Graesser, 2004). An index showing the causal complexity of a text is CAUSC, the ratio of causal particles to causal verbs. Lower ratios point to lower causal cohesion because there are comparatively less particles signaling connections between the events.

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Why are the paragraphs processed differently by stydents? CAUSC equals 0.67 for the Cartesian Diver passage and 1.67 for the Heating passage. That result points to a greater difficulty in understanding causal relations in the former passage compared to the latter. This is consistent with the greater frequency of explanation questions in the Cartesian Diver passage.

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Study II The second study involved 65 students attending the 12th grade. The Heating passage was substituted by another, Ethanol Gun so that it could be of comparable difficulty to the Cartesian diver passage. Two conditions were used in this experiment: reading for understanding reading for experimenting

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Ethanol Gun In order to understand how cannons function, the ethanol gun (gun with vulgar alcohol) can be used. The Ethanol Gun is prepared sticking a great iron nail of each side of a strong bottle. The extremities of the two nails must be to a concrete 0,6 m distance one of the other and without nothing between them. About 1 mL of ethanol is lain down inside of the bottle and it is agitated very well. It is covered later, with a well adjusted cork. Then, the bottle is fixed to a support, with security, with the mouth slightly turned for the top. With an electric lighter one becomes to jump a spark on the head of one of the nails stucked in the bottle. A noisy explosion occurs and the cork is gone for the other side of the room. A Chemist would explain that an explosion is produced because a combustion reaction inside the bottle happens. The combustion is an exothermic reaction of the ethanol with the oxygen of the air provoked for the spark. Its clear that the combustion increases the pressure inside the bottlebecause the reaction increases the temperature very much. This explains why the cork is gone off as a cannon bullet.

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Study II Results A significant effect of task condition was found. Reading for understanding Type II questions Reading for experimenting Type I questions

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Study III 145 9th grade students participated in the this study. The reading goals of these students were the same _ Understanding and Experimenting, but they more specific: reading for rewriting a text (Understanding) reading in order to carry out an experiment (Experimenting). The text has two paragraphs Introductory Presenting the problem Procedimental Key sentence

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The general condition Mixtures in Metal Objects (Gold Rings ) A person wants to buy an object of a precious metal that someone tries to sell. However, suspects that this object has mixed metal that is more cheap. The object weighs 10 grams, the doubt is that it contains exactly those 10 g of pure metal. One way to check if the object is made of pure metal or whether it is a mixture, is to place it in a liquid and measure the volume fluid displaced. In fact, it is very common that these objects are not made of pure metals. Study III

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No differences due to text were found. Questions on the whole paragraph More T1questions More T2 questions per student were asked on the rewriting condition (nT2= 0.8 ) than in the experimenting condition (nT2= 0.4) But more T1 questions per student were asked in the experimenting condition (nT1= 2.5 ) than in the rewriting condition (nT1= 1.9 ). There were a few T3 questions Study III Results

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Questions on the key sentence/procedimental nT1 experimenting> nT1 rewriting, as in the whole paragraph nT2 experimenting =nT2 rewriting The obstacle in the key sentence is not directly causal. Study III Results

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STUDY IV 60 9th grade students from one secondary school in Seia, Portugal. A new text was written Gold mixtures and other metals that explained again how to detect mixtures in metal objects. The text includes two distinct parts: An introductory paragraph A procedimental paragraph Reading goals were similar to those on first study: Rewrite the text. Plan and do an experiment

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Mixtures of metal objects Gold is used in jewellery because it does not deteriorate with time. However, pure gold should be mixed with other metals to make jewels. Therefore, a gold ring has a fraction of pure gold only. A simple experiment allows one to know this fraction. First, the ring is weighted in a balance with enough precision. The ring is put into water using an appropriate container. The volume of displaced water is measured with exactitude. This volume and the weight of the ring determine the proportion of gold.

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Results confirmed the influence of reading goals on questioning Text characteristics appears as a moderator variable of that relationship. More T2 questions asked in the understanding condition always. Providing explanations seems to be a tacit aim in understanding More T1 questions asked in the experimental condition only for the procedural paragraph. Otherwise less T1 questions. Readers do not spontaneously elaborate a text, as found in other studies on inferences. STUDY IV Discussion

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Study IStudy IIStudy IIIStudy IV Reading GoalsNo effectExperimenting > TYPE I Understanding > TYPE II Experimenting (Plan and do the experiment) >TYPE I Understanding (Rewrite the text) > TYPE II Experimenting (Plan and do the experiment) >TYPE I Understanding (Rewrite the text) > TYPE II TextA significant effect Cohometrix Causality A significant effect Cohometrix Causality Procedimental Text Understanding T1=T2 Key sentence (Procedimental) T1>Experimenting

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Questions Type I Questions Type II Qyestions Type III Reading GoalsExperimentingUnderstanding TextProcedimentalIntroductory/ Declarative TextLow causality cohesion

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How to write science school texts?

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There is strong evidence that the goals established influenced the students questioning. However this result is more evident when reading goals are specified. Therefore, it is important to formulate and present reading goals Reading goals must be formulated in a clear way.

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How to write science school texts? A sequential and also hierarquical model can be established that guides the organization of pedagogical situations and text writing. Concepts are really understood when they can be put to practice/exemplified in experiments. Only after, they can explain the scientific phenomena. It is important to present examples/cases, first, and only after formulate patterns. Comprehension leads to causal relations, in a higher cognitive world. Misunderstanding them, will lead to alternative conceptions.

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There exists also a moderate evidence that the text features are associated with the formulated questions. Text features generate different questions. Describe/explain or procedure ? Or both? Write texts with a degree of challenge. Write different kinds of science texts for different educational goals. Nevertheless deeper investigation is needed in this area. How to write science school texts?

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Thank you