Science, maths and technology
Updated: 2008-02-16
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Topic 1 Science, maths and technology
Science is concerned with gathering information by investigation
reorganizing the information to get patterns and regularities looking
for explanations and communicating findings to others. Finding patterns
and regularities simplifies the descriptions of observations.
Observations are information gained by using the senses. Investigations
may be qualitative requiring general observations or quantitative
requiring counting or measuring. Science teachers should conduct
investigations so that the students can observe phenomena before
listening to interpretations. The teacher should not say too much but
should let the experiment speak for itself. Effective teachers select
content, skills and learning experiences in the subjects they teach
which will foster students intellectual and personal growth. Teachers
should be able to express subject aims and goals for what students
should expect to gain from their learning experiences and organize
subject content coherently and at a level that is appropriate to the
student group and their learning.
This document contains ideas on practical teaching for the trained
science teacher. Students should not use this book unless under the
supervision of the science teacher. After choosing an experiment from
this book, the teacher should practice the experiment before
demonstrating it to students or before requiring students to do it. The
teacher has the duty of making the decision about whether the
experiment is safe for the children in the class.
Topic 2. Role of practical work
"The role of practical work", by Rod Watson, School of Education,
King's College London, UK, from Chapter 4 "Good Practices in Science
Teaching" Open University Press, UK ISBN 0 335 20391 4 (pb) First
published 2000 Reprinted with permission.
Rod Watson is a senior lecturer in chemistry education. He has taught
in schools in UK and in Spain. The focus of his research is the role
of investigations and practical work in science education, and he
has directed two major research projects in this area. All the 16
contributors to "Good practices in science teaching" work in, or are
associated with, the School of Education, King's College London. The
book is available from Open University Press.
The role of practical work
by Rod Watson
Empirical work is one of the defining features of science. Many
countries devote considerable resources to give students of science the
opportunity of doing practical work in their science lessons (Beatty
and Woolnough 1982; Watson and Prieto 1994). Does it work? Is it
worth the investment? Can it be used more effectively? Many scientists
and science educators are convinced that practical work must play an
important role in learning science, but the reasons for its prominence
are less clear. This lack of clarity lies in the vagueness of the
questions asked about the role of practical work. Asking about the
effectiveness of practical work for learning is like asking whether
children learn by reading. The answer lies in the nature and contents
of the activities and the aims which they are trying to achieve. Just
as there is a great variety of styles and contents of reading matter,
there is also a great variety of kinds of practical work. A more
focussed question is to ask what kinds of practical activities can be
used to achieve particular aims. Practical work may be used in a
variety of formats such as practicals following recipes,
investigations, skills training, teacher demonstrations to promote
discussion about phenomena and raise questions, problem solving
activities, and heuristic practical activities designed to help
students induce generalizations.
This chapter looks at practical work - its aims, its effectiveness, its
use for teaching conceptual aims, and the strategies for the
development of practical procedural knowledge and its use in
investigations.
Aims: What is practical work? What is it for?
Several studies have collected teachers' views on the aims of practical
work. Of particular interest are the studies of changes over time. Ten
aims in the Kerr (1964) survey were augmented by a further ten in the
Beatty and Woolnough (I 982) survey. That set of 20 aims was again used
in the Swain et al. (1998) study. Despite changes in the kinds of
practical work done over time, in all three studies four aims remained
the most popular:
to encourage accurate observation and description;
to make phenomena more real;
to arouse and maintain interest;
to promote a logical and reasoning method of thought.
There is, however, a cluster of aims that were rated more highly in the
Swain et al. study in 1998 than those in the Beatty and Woolnough study
in 1982. They are:
to practise seeing problems and seeking ways to solve them;
to develop a critical attitude;
to develop an ability to cooperate;
- for finding facts and arriving at new principles. Following the
introduction of more open investigation work in the National Curriculum
in England, this change in emphasis of aims is a product of a change in
the kind of practical work used.
The messages here are clear. Teachers see both procedural and content
aims as part of the core of practical science and as inextricably
related to one another. For example, in order "to encourage accurate
observation and description" one has to observe some phenomenon and,
reciprocally, accurate observation and description aids in making
phenomena more real. Beyond these core aims are different sets of aims
associated with different kinds of practical work. The difficulties of
trying to achieve too many aims through one activity are discussed by
Woolnough and Allsop (1985). They argued for different kinds of
practical activity for different aims: that is, short illustrative
tasks to stimulate discussion and learning about concepts; practical
activities to develop practical skills and procedures; and more
extended and open practical experiences to develop investigative
skills.
The effectiveness of practical work in general
Hodson (1993) has reviewed the effectiveness of practical work under
four headings: motivation, acquisition of skills, learning scientific
knowledge and the methods of science, and scientific attitudes. The
results of his study indicate that, in each of these areas, school
practical work leaves much to be desired.
On the whole, students enjoy practical work and develop positive
attitudes to it, but this enjoyment is qualified. A significant
minority of students express a dislike for practical work (Head 1982),
and enthusiasm for practical work of ten declines with age (Lynch and
Ndyetabura 1984). What appears to be important is not whether students
do
practical work but the kinds of practical work used. Open kinds of
practical work are seen by teachers as very motivating - motivation is
improved if students feel a sense of ownership of investigations (Kempa
and Dias 1990; Jones et al. 1992) and greater control is given to
students.
Several studies have shown variable success in performing practical
tasks (for example APU 1982,1985; Gott and Duggan 1995: Chapter 5). The
TIMSS (Third International Mathematics and Science Study) shows great
variability between countries, with grade 8 students in Singapore and
England performing significantly better (Harmon et al. 1997) than
students in other countries, on practical tasks designed to test skills
such as:
measuring; the use of simple experimental and mathematical procedures;
designing and implementing approaches to solve problems or investigate
phenomena;
synthesizing knowledge, application, and personal experience into an
interpretation of the data.
There is also variability between different skills and process. For
example, in the APU study (1985) 15-year-olds were asked to read
pre-set values on several simple measuring instruments. Fewer than one
in five correctly read an ammeter and only about half correctly read
the value on a rule. Performance was better in reading a thermometer
and a force meter. In making and interpreting observations, however,
about 50% of students performed simple observations
successfully.
Planning investigations was a strength of students in the APU (1982)
study, and 15 years later an analysis of the TIMMS data (Harmon et al.
1997) shows that this has been sustained.
Hodson (1993) reported that the research literature indicates that
there is little to show that practical work is effective in helping
students to learn scientific knowledge, and that some reports suggest
that it is less successful than other methods. A recent study by Watson
et al. (1995) gave typical results. The understandings of two groups of
150 15-year-old students were compared. One group had been exposed to a
curriculum with a high practical content (in England) and the other
group with a low practical content (Spain). In spite of having
much more practical experience with combustion, the English
sample showed few differences from the Spanish sample in either their
scientific or naive conceptions about combustion. What may be more
import ant than the quantity of practical work is what use is made of
it in helping students to develop scientific concepts. Hodson (1993)
reports a similarly disappointing picture with regard to learning about
the nature of the methods of science.
He also challenges the efficacy of practical work in teaching
supposedly scientific values such as taking a value free stance, being
objective, open minded and willing to suspend judgement. In contrast,
school practical science is dominated by the need to get correct
answers and find out what ought to happen; to ensure conformity with
the answer in the textbook in such conditions it is difficult to see
how such attitudes can be generated (Hodson 199 3). Mahoney (I 979)
maintains that scientists frequently display different characteristics
anyway: they are often illogical in the way they work, highly selective
in reporting data, and that they will stick tenaciously to their views
even in the face of contradictory evidence. This brings into question
the value of trying to teach such values when recent scholarship in the
philosophy and sociology of science casts doubt on how representative
such values are. In consequence, Hodson concludes that there needs to
be a fundamental rethink of the role of practical work in school
science.
Turning from a review of the effectiveness of practical work, this
chapter now examines research that explores how practical work may be
improved in two broad areas: developing understanding of scientific
concepts and developing the capability to do scientific
investigations. This next section reviews how practical work may be
used to develop conceptual understanding and the rest of the chapter
then focuses on what is meant by scientific investigations and how
students can be taught to investigate.
How practical work can be used to achieve conceptual aims
"I listen and I forget, I look and I remember, I do and I understand."
This so-called Chinese proverb summarized the discovery learning
approaches of the Nuffield science projects of the 1960s and 1970s.
When reflecting on the work on students' understanding of scientific
concepts, Ros Driver reformulated the proverb as "I listen and I
forget, I look and I remember, I do and I am even more confused!"
There is a belief among science teachers that practical experience of
phenomena is essential for understanding scientific concepts. Recall of
incidents, or episodes (White 1988: 3 1), in the laboratory gives a
dimension to scientific concepts that cannot be achieved simply by
talking about them. However, progression from observations of phenomena
to the construction of scientific concepts is not a simple one.
Scientific concepts and theories are often counter-intuitive and have
to be constructed in the classroom by talking or reading about
phenomena as well as by seeing them. Here, two case studies have been
selected from the large number of studies in this area to illustrate
the importance of the teachers in teaching students to
construct
conceptual understanding in the classroom. One shows the use of a
demonstration within a social constructivist approach to learning, and
the other the use of practical work in a fairly traditional classroom.
Scott and Leach (1998) describe a teaching episode in which the teacher
is building on the idea that reducing the amount of air in a fixed
space reduces the air pressure in that space. The teacher sets up a
demonstration with two partially inflated balloons inside a bell jar.
The air is then sucked out of the bell jar using a vacuum pump and the
students see the balloons slowly inflating. The students are
entertained by
this unusual sight and start offering their explanations. The
scientific explanation of these observations does not flow naturally
from simply seeing the demonstration. Students are used to the everyday
idea that sucking on a straw, sucks up the drink and tend to use a
similar explanation that the air is sucked out of the bell jar and
sucks out the walls of the balloon. The teacher's role is to help
students to understand and use the scientific explanation. To do this,
the teacher focuses on key aspects of the demonstration, selecting and
emphasizing particular aspects of students responses: he points out
that
the balloons are tightly sealed (that is, the quantity of air in them
is fixed); he selects a response from one boy who focuses on the
decrease in pressure in the bell jar, praises him for his explanation
and then repeats in a slow and deliberate voice, "So if you make less
air in the jar there's less air pressure in the jar . . ." What this
shows is that the teacher is crucial in introducing a new way of
talking about the phenomenon, relating selected observations to a
scientific explanation. Observations alone are insufficient.
The importance of the teacher as a mediator and interpreter of the
observed physical phenomena is also seen in a second example - a case
study described by Roth et al. (1997) and McRobbie et al. (1997). These
two papers describe different aspects of six weeks of observation of a
physics teacher and his grade 12 students, doing practical work in
groups. Different students responded to the lessons differently
(McRobbie
et al. 1997). The responses were also different from what the teacher
anticipated (Roth et al. 1997). The teacher expected students would see
the phenomena studied in the same way as he saw them, whereas the
students came to the practical activity with their own ideas about
motion, and this affected what they observed (Roth et al. 1997). The
teacher also expected that his instructions were self-evident, but
failed to realize that the students did not share his theoretical
perspective, which made sense of the practical activities. The result
was confusion for the students in understanding what they were supposed
to do. The role of the teacher in helping students to construct the
accepted scientific view is illustrated in the variable response of the
students. Students who felt able to ask many questions were able to use
the information provided to understand the accepted
scientific view (McRobbie et al. 1997), whereas the others were left
struggling with their own interpretations of the phenomena.
Learning to Investigate
What are investigations? Teachers working in England and Wales have
identified the following two characteristics of investigations.
In investigative work students have to make their own decisions either
individually or in groups: they are given some autonomy in how the
investigation is carried out.
An investigation must involve students in using procedures such as
planning, measuring, observing, analysing data and evaluating methods.
Not all investigations will allow students to use every kind of
investigation procedure, and investigations may vary in the amount of
autonomy given to students at different stages of the investigative
process.
(Watson and Wood-Robinson 1998: 84)
The same kinds of justifications have been used for including
investigations in the curriculum as those used for practical work in
general. The major aim for investigations for many teachers is to
develop the use of the procedures of science (Watson and Wood-Robinson
1998) with teaching for conceptual understanding taking second place. A
third possible aim is to develop students' understanding of the
relation
between empirical data and scientific theory (Driver et al. 1996).
The APU (1982) envisaged investigation as a cyclical process in which
students worked through different stages of an investigation: problem
generation and perception, reformulation, planning, carrying out
practical work by making observations and measurements, recording data,
interpreting, evaluating the various preceding stages, and finally,
reaching a solution. Investigations were seen as processes which
brought together students' conceptual understanding, scientific skills
and processes to solve a problem. The work of the APU was concerned
with assessing student achievement in specific domains. So, to
focus on scientific skills and processes, assessment tasks were
designed which made low demands on students' knowledge and
understanding.
However, many of these investigations have become incorporated in
current curricula, resulting in an artificial separation between
experimental/investigative work, and the knowledge and understanding
components of the curriculum.
The APU model also placed a heavy emphasis on relations between
variables leading to the domination of "fair testing" in UK curricula.
Fair testing describes investigations where an independent variable is
manipulated to have an effect on a dependent variable, while
controlling all other relevant variables. The range of kinds of
investigations which fit easily within this model has been criticized
as being limited as they fail to represent the variety of methods used
by scientists and over-emphasize fair testing (Watson et al. 1998). At
ages 11-14 in England and Wales, over 80% of all investigations
are fair tests. This means that, if the habitat of animals such as wood
lice is being explored, it is much more likely to be done in the
laboratory using choice chambers (fair testing), than outside in the
natural environment (pattern seeking). Other kinds of investigations
such as classifying; identifying; pattern seeking; exploring;
investigating models; and making things and developing systems are
rarely used (Watson et al. 1998,1999a and 1999b). As well as being
dominated by fair testing, the variety of investigations within the
fair testing category tends to be very restricted. For example, 16% of
all fair testing investigations done at age 11-14 were
investigations of variables affecting solubility or rate of dissolution
(usually of sugar)!
Teaching and learning scientific procedures
There has been much discussion about the different ways in which
scientists go about investigating nature (see Chapter 5). It is now
commonly agreed that there is no one scientific method but that
scientists work in a variety of ways (Millar and Driver 1987).
Scientific skills and processes - the procedures of science - are,
however, applied within a variety of different contexts and
investigations. However, although the ways in which they are utilized
may
vary, there are still some procedures common to many kinds of
investigations. It is to these procedures that we now turn.
The APU (1988) developed test items for different scientific activities
under the headings:
use of graphical and symbolic representation;
use of apparatus and measuring instruments;
observation;
interpretation and application;
planning of investigations; and
performance of investigations.
National surveys of students performance were carried out at ages I 1,
13
and 15. The findings are reported in four series of reports: reports
for teachers (for example Gott and Murphy 1987), research reports (for
example APU 1982), reviews of findings (for example APU 1985) and
reports looking in more depth at specific skills of process (for
example Strang et al. 1991). These reports paint a fascinating picture
of students performance, giving detailed information about progression.
However, one question that remains unanswered in the APU surveys is the
extent to which the test items measure skills and processes that can be
transferred to other contexts, and to what extent they are measuring
skills and processes that are situated in the particular context of the
test item: differences in performance cannot satisfactorily be
disentangled from the impact of other aspects of questions,
particularly the apparent linguistic demand. Moreover, even within
groups of questions collective performance varies markedly,
indicating the impact of factors which are unidentified.
(APU 1988:93)
One effect - that of context - was studied by constructing equivalent
test items in everyday and school science contexts (Song and Black
1991, 1992). Its effect on performance varied according to the skill
being tested, but often the everyday context seemed to cue students
into a less scientific way of working.
Whether processes are situation specific or transferable is a question
also addressed by Millar and Driver (1987). They argue that the
commonly cited "processes of science" cannot be divorced from the
content and context, which actually give meaning to so-called
"process
based" activities in science. This argument is illustrated using the
processes of observing, classifying and hypothesizing to show that
these only become scientific processes when being used for a scientific
purpose. In other words, scientific processes and scientific knowledge
and understanding are inextricably linked.
The Procedural and Conceptual Knowledge in Science (PACKS) Project
(Millar et al. 1994; Lubben and Millar 1996) explored the influence of
procedural and conceptual knowledge on students' performance in
investigative tasks and, in so doing, developed a model of procedural
understanding.
A central feature of the PACKS model is that procedural understanding
is a knowledge based domain. It is similar to other science "content"
domains, in that children have prior ideas, and
that these ideas may need to be developed or changed through teaching.
The domain of scientific evidence contains ideas which must be taught.
(Millar et al. 1994: 245)
Those ideas which must be taught - what they term "concepts of
evidence" are described as comprising those associated with:
design: variable identification, fair test, sample size, variable
types;
measurement: relative scale, range and interval, choice of instrument,
repeatability, accuracy;
data handling: tables, graph type, patterns, multivariate data.
In the PACKS model there is a shift in emphasis compared with the APU,
with much more stress being placed, in the former, on understanding the
quality of evidence collected rather than on carrying out a particular
process. For example, in measuring, the APU focuses on using measuring
instruments whereas the PACKS model focuses on "understanding the
appropriate degree of accuracy that is required to provide reliable
data which will allow meaningful interpretation."
This redefinition of skills and processes as procedural understanding
leads to the conclusion that there is now "a need to devise activities
which progressively develop and refine children's understanding of the
purpose of scientific investigation, and of the key concepts which
underpin judgements about the quality of data" (Lubben and Millar
1996). This is similar to the conclusion reached in the "content" area:
it is not enough simply to use scientific processes in carrying out
a practical activity, but there is also a role for the teacher in
helping students to understand the underlying concepts of evidence.
Curriculum materials have now been designed to teach such concepts
(Foulds et al. 1997, 1998).
Teaching and learning in whole investigations - students'
interpretation of investigations
The learning of scientific procedures in separate activities and in
whole investigations is different. Whole investigations provide a
context in which there is a scientific purpose. However, do students
see this
scientific purpose? Research indicates that many do not. Kuhn (1989)
proposed a sequence in the development of children's understanding of
the relation between theory and data. In the early stages, theory and
data are fully integrated and are used interchangeably: children see
the purpose of collecting experimental data as being to discover how
the physical world works. For example, some young children, when asked
to explain what has happened to the water in a puddle that has dried
up, will say that it has disappeared. For them, the phenomenon and the
explanation are one and the same thing.
Later, when theory and data are compatible, students tend to mould them
together as "the way things are", but, when theory and data are
incompatible, conflict is avoided by strategies such as selective
attention to data. Only in the upper levels of the developmental
spectrum are theory and data consciously differentiated. For example,
students who observe copper turning black on heating are able to
consider
different theoretical explanations for the phenomenon: the heat may
have changed the copper to carbon, or the heating may have caused
copper to combine with oxygen to form a black product. Here the theory
is clearly separated from the data. Driver et al. (I 996) used a
similar framework distinguishing reasoning about phenomena, reasoning
about relationships and reasoning about models in children of three
ages. The results indicate that the ability to produce a consistent
argument, relating evidence and explanation, increases with age with
only a minority producing a consistent argument at age 9, rising to
more than half at age 16.
In their study of investigative work, Millar et al. (1994) noted four
kinds of response: an engagement frame, in which students engaged in
activities without obvious plan or purpose; a modelling frame, in which
they tried to produce a desired effect; an engineering frame in which
they tried to optimize the effect; and a scientific frame. Although the
use of the scientific frame increased from ages 9 through 12 to 14,
still only a minority were using the scientific frame at age 14. The
author (Watson 1994) studied groups of students carrying out practical
investigations in a normal classroom setting and explored the factors
that influence the approach of groups of students to an investigation.
The findings showed that some students were found to do the
practical activity with little purpose (engagement frame), but it was
possible to influence the way the groups worked by explicitly focussing
on the relationships between the research question and the data being
collected by providing thinking time within the lesson structure, and
by focussing classroom talk on the rationale behind the investigative
strategies being used rather than on what was being done.
Openness of investigations
Carrying out whole investigations can be seen as a process of making a
series of decisions. This means that students must have enough
autonomy to be able to make decisions for themselves (Qualter et al.
1990; Woolnough 1991). Johnstone (1997), however, warns against
overloading students' short-term memory and recommends structuring
lessons in such a way as to reduce demands on the short-term memory.
Students' decision making can also be supported by providing activities
designed to scaffold students' thinking. The difficulty of achieving an
appropriate balance between providing structure to support students'
thinking, and providing a structure that directs students to do an
investigation, in a pre-determined way is illustrated in Watson and
Wood-Robinson (1998). Teachers were often unaware of the extent to
which they were making most of the important decisions. Teachers
sometimes frame an investigation very heavily, leaving little for
students to decide.
One aspect of giving students autonomy over their own learning is
whether
they can use the autonomy effectively to achieve the desired learning
goals. Watson et al. (1998) compared teachers' aims for specific
investigation lessons with what their students thought they learned.
Over
50% of the teachers' aims were procedural, such as proposing
hypotheses or planning a fair test, compared with 20% of
student
responses. Most student responses (74%) were about
learning content compared with 33% of teachers' responses. The
mismatch between teacher and student perceptions is striking. Students
concentrate on more surface features of investigations: If they are
given a task "to investigate the factors affecting the rate of sugar
dissolving in water", they tend to see the purpose of the lesson being
to learn about dissolving. Similarly, when they mentioned procedures,
half their responses were very specific (for example, to learn to
operate a balance). It is more difficult for students to recognize the
gradual learning of scientific processes such as developing better fair
testing strategies or approaches to planning. The implication,
therefore, is that a key task for teachers is to communicate
effectively to students what the educational aims of the investigation
are; to differentiate between the aim of answering the question being
investigated and the educational aims of activity.
Providing structure in an open situation
Two approaches to providing support in an open situation are through
the overall structure of the investigation lessons, and through the
organization of the activities within the different sections of the
lessons. Watson and Wood-Robinson (1998) describe a lesson structure
used to report 32 investigations carried out by teachers of students
aged 7 to 14. The lesson structure can be simplified into three phases:
a thinking phase before collecting evidence;
the collection of evidence;
a thinking phase after collecting the evidence.
The initial thinking phase includes a focus on relevant knowledge and
setting the problem in context, allowing students to clarify and refine
the problem, and then planning what they are going to do. Typically,
teachers spent about a third of the investigation time on these stages.
In the next stages the focus is more on practical activity: making
measurements and observations, recording and describing results and
presenting their results in different forms. The focus then shifts back
to thinking about what the evidence means: interpreting the results,
evaluating the quality of the evidence collected and students
reflecting on their own learning. Even when teachers planned time for
the later thinking phase, this was often eroded because other parts of
the investigation took longer than expected. The result was that the
latter stages of the investigation were often either done alone at home
or not done at all. This was seen as a serious weakness. For, if one of
the purposes of investigative work is to develop a better understanding
of evidence and its role in science, it is essential that time is given
to critically analysing and discussing the interpretation and meaning
of the data that students collect. The teacher has an important role in
focussing on significant aspects of students' investigations, in
challenging them to defend the quality of their evidence and arguments,
and in creating a classroom environment in which students become
critical
of their own and others' evidence. As well as providing support through
the structure of the lessons, support can be provided within different
stages of the lessons. Two illustrative examples are given below.
One way of providing guidance for students in the first thinking phase
is
using a sequence of displayed questions (variously called planning
sheets, prompt sheets or planning boards). Watson and Wood-Robinson
(1998) found that such scaffolds are very common, with many teachers
using them most or all of the time. The effectiveness of such scaffolds
depends on how they are used. They can be used like a traditional
worksheet, almost like a recipe, to take the students through the
investigation stage by stage. Used in such a prescriptive way, there is
little opportunity for students to learn to make decisions.
Alternatively, and more efficiently, they can be used to display and
discuss the main features of students' thinking and can be used to
expose this thinking for discussion either within a group or with the
teacher.
Another aid to planning is the use of a variables table (Jones et al.
1992; Watson and Fairbrother 1993). In this study students identified
the
key variables relevant to their investigation as headings to columns on
a blank table. Having brainstormed all the things that could be changed
in their investigation, they wrote the variable they want to find out
about (the outcome or dependent variable) as the heading for the last
column. All the other variables that might affect the outcome were used
as headings for the other columns. They then chose one of these as the
independent variable and chose different values for it. The remaining
columns represented control variables. The teacher was then able to
meet the group, peruse the table and engage the students in discussion
about their thinking. For example, Table 4.1 reveals that the group had
not considered the effect of temperature on the rate of growth and had
not written down exactly what aspect of growth they would examine.
Table 4.1 Example of a student's table of variables
| Water |
Soil |
Plants (grass seedlings) |
Amount of Light |
Growth |
| 20 mL |
Bag of soil |
2 cm |
Dark cupboard |
- |
| 20 mL |
Bag of soil |
2 cm |
Natural light |
- |
| 20 mL |
Bag of soil |
2 cm |
40 W bulb in 24 hours |
- |
These two devices are not merely scaffolds for students, they are tools
to expose students' thinking and make it more accessible to discussion
and development.
Closing thoughts
Practical work is one of the hallmarks of science, and many educators
argue that a science education without practical work fails to reflect
the true nature of scientific activity. This has led to a widespread
acceptance in many countries of a strong emphasis on students doing
practical work. There is now a need to examine carefully the purposes
of different kinds of practical activity to select appropriate
strategies for achieving different aims. Some clear messages emerge
from the literature.
Scientific skills and processes are embedded in the context of the
particular scientific purposes that they serve. Theory and practice are
interrelated.
Practical work has in the past been seen, not surprisingly, as a
practical activity - doing things. Research indicates that this is not
enough. Practical work needs essentially to be about thinking: that is
about trying to understand the relations between evidence and theory
and to stimulate and challenge students. This is particularly true in
investigations and so it is important to provide time for discussion
and to encourage students to make their ideas explicit.
Explicit teaching of concepts of evidence is recommended. There is,
however, a difficult balance to be struck between providing support
which gives students enough freedom to make decisions for themselves,
and imposing a structure in which the teacher has made most of the
important decisions.
Autonomous learners need to be aware of the educational purposes of
activities in which they are engaged (see Chapter 2 on formative
assessment).
References
APU (1982) Science in Schools: Age 13, Research report. London: DES.
APU (1985) Science at Age 15, Report No. 1. London: DES.
APU (1988) Science at Age 13, Review report. London: DES.
Beatty, J. W. and Woolnough, B. E. (1982a) Why do practical work in
11-1 3 science? School Science Review, 63: 758-70.
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