Writing challenging science texts: pedagogical implications from research about students question...
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Writing challenging science texts: pedagogical implications from research about students question generation Piedade Vaz-Rebelo [email protected]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
Writing challenging science texts: pedagogical implications from research about students question generation Piedade Vaz-Rebelo [email protected] Faculty
Writing challenging science texts: pedagogical implications
from research about students question generation Piedade Vaz-Rebelo
[email protected] 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
Slide 2
The research a set of empirical studies have been developed
addressing question generation when subjects process written
information.
Slide 3
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.
Slide 4
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.
Slide 5
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.
Slide 6
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).
Slide 7
Other variables moderator variables Input Goal TEXT OBSTACLES
MENTAL REPRESENTATION Question generation Text characteristics
Slide 8
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.
Slide 9
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
Slide 10
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.
Slide 11
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.
Slide 12
Results
Slide 13
-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
Slide 14
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.
Slide 15
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.
Slide 16
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
Slide 17
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.
Slide 18
Study II Results A significant effect of task condition was
found. Reading for understanding Type II questions Reading for
experimenting Type I questions
Slide 19
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
Slide 20
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
Slide 21
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
Slide 22
Slide 23
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
Slide 24
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
Slide 25
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.
Slide 26
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
Slide 27
Slide 28
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
Slide 29
Questions Type I Questions Type II Qyestions Type III Reading
GoalsExperimentingUnderstanding TextProcedimentalIntroductory/
Declarative TextLow causality cohesion
Slide 30
How to write science school texts?
Slide 31
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.
Slide 32
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.
Slide 33
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?