Lee
A problem-solving approach to STS
Kidney failure and dialysis:
a problem-solving approach
in teaching Science,
Technology and Society
Yeung Chung Lee
How can we engage pupils in learning STS, apart from employing
common approaches like data analysis, case studies and class debate?
Science, Technology and Society (STS), a term first
suggested by Ziman (1980), has become a catchphrase
to describe an approach to studying science and
its interactions with technology and society. STS
elements have been incorporated into the science
curricula to different extents in different places. In
the UK, starting from key stage 2 (ages 7–11), pupils
are expected to ‘think about the positive and negative
effects of scientific and technological developments
on the environment and in other contexts’; and
in key stage 4 (ages 14–16), pupils ‘explore how
technological advances relate to the scientific
ideas underpinning them’ and ‘consider the power
and limitations of science in addressing industrial,
ethical and environmental issues’ (DfEE/QCA,
1999). The National Science Education Standards of
the United States incorporate STS elements within
the ‘Science and Technology Standards’, which
‘establish connections between natural and designed
worlds’, and within the ‘Science in Personal and
ABSTRACT
This article describes the use of a problemsolving approach in teaching a Science,
Technology and Society (STS) issue. A scheme
of work is presented which engaged secondary
biology pupils in devising treatment methods for
patients suffering from chronic kidney failure.
Through the problem-solving process, pupils
were led to understand and appreciate how
science is applied to solve an important health
problem. Apart from enhancing motivation
and engaging pupils in the learning process,
evaluation showed that the approach had the
added value of clarifying pupils’ misconceptions
of important physiological processes.
Social Perspectives Standards’, which ‘give students
a means to understand and act on personal and
social issues’ (National Research Council, 1996). In
Hong Kong, the new senior secondary biology and
physics curricula incorporate ‘STS connections’ as
an extension to traditional content areas (Curriculum
Development Council, 2002a, 2002b).
Many of these curricula advocate an issue-based
approach in teaching STS, focusing on the socioeconomic, environmental or ethical impact of issues
arising from the application of various branches
of science. Common issues are air pollution, GM
food, cloning and mobile phones, to cite just a few.
Approaches such as data analysis, case studies,
discussion and debate are commonly used to achieve
the objectives. To extend our repertoire of teaching
approaches, this short article uses chronic renal
failure as an issue to explore an alternative approach
to teach STS. Pupils were engaged in a problemsolving activity that required them to apply scientific
knowledge gained from their biology class. Through
the problem-solving process, pupils could more
readily understand and appreciate how scientific
knowledge bears on the resolution of human or
societal problems.
Background to the problem
Hundreds of thousands of people around the world
are suffering from chronic renal failure as a result
of different kinds of diseases or disorders. While
there is a general shortage of kidneys available
for transplant, dialysis is a viable option to sustain
their lives until transplant. Dialysis is the means for
removing wastes and excessive fluid from the body
to maintain its proper functioning. It is supposedly
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A problem-solving approach to STS
Lee
Figure 1 Set-up for performing peritoneal dialysis.
employed as a short-term treatment option so that
people’s lives can be sustained while they are
waiting for kidney transplant. However, in view of
the limited number of donors, dialysis has become
the only kind of treatment available to many patients.
It is estimated that more than one million people
worldwide are dependent on some forms of dialysis
(Baxter, 2006). At present, two options of dialysis
are available to these patients: haemodialysis and
peritoneal dialysis. In haemodialysis, the blood of
the patient is pumped through a very long tube made
of artificial dialysis membrane contained in the socalled ‘kidney machine’. Waste substances diffuse
from the blood to the surrounding dialysing solution,
or dialysate, through the membrane, because there is
a concentration gradient between the two media.
Peritoneal dialysis was developed more recently.
In this form of dialysis, the dense capillary network in
the peritoneum, which lines the abdominal cavity and
the gut, is used as the dialysis membrane. Dialysate
is introduced into the abdominal cavity through a
tube called catheter. Just as in haemodialysis, toxic
substances and water move out of the blood into the
dialysate, but this time through the blood capillary
wall instead of an artificial dialysis membrane. The
dialysate is kept in the body for a few hours before it
is drained from the abdomen. New dialysate is then
introduced so that dialysis can take place 24 hours a
day. Figure 1 shows how the dialysate is drained out
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by siphonage and new solution is introduced into the
abdomen by gravity.
With some training, the patient can administer
the treatment at home, hence allowing them to
lead fairly normal lives. Apart from this, patients
under peritoneal dialysis have a more stable blood
composition than those under haemodialysis, since
dialysis takes place more or less continuously within
the body. However, the risk of peritonitis is great
since bacteria may enter through the artificial opening
to the abdominal cavity. Neither of these forms of
dialysis can replace the kidneys, as these have other
functions such as the secretion of erythropoietin
essential for production of red blood cells.
The problem-solving activity
The following activity was tried out with two classes
of 15–16 year-olds in a Hong Kong secondary school,
a total of 79 pupils. They were of average ability
and had learnt about the functions of the kidney
and the principles of diffusion and osmosis. They
had performed dialysis by using Visking tubing to
separate starch from glucose. The aim of the activity
is to enable pupils to understand the role of dialysis
in treating renal failure and to enhance their problemsolving ability. The lesson lasted for approximately
one hour and twenty minutes. At the beginning of
the lesson, pupils were presented with the problem:
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‘How can waste substances be safely removed from
the body of patients suffering from chronic renal
failure?’ Then they were asked to design a simple
system to solve the problem, utilising the knowledge
they had acquired in previous biology lessons.
Materials and apparatus
The pupils were provided with the following:
Visking tubing, string, distilled water, syringes,
beakers, test tubes, test-tube rack, droppers, blotting
paper, bromothymol blue, urease, electronic balance,
materials for making a ‘blood’ sample (sucrose,
glucose, starch, proteins, amino acids, salts, urea,
distilled water).
Guidelines on procedure
To assist the pupils through the enquiry, the following
guidelines were provided:
1 Make up a ‘blood sample’ with the substances
provided. (You should select only the substances
present in human blood.)
2 Construct a set-up to remove wastes from your
‘blood sample’ using the materials and apparatus
provided. Draw your design.
3 Predict what will occur when the system is left
running for some time.
4 Briefly describe the tests you will conduct before
and after the experiment to check if your system
works. [It was suggested to pupils that it would
be helpful to measure the weight of the ‘blood’
sample in the Visking tubing using the electronic
balance. The test for the presence of urea in a
solution sample was provided to pupils since
they had not done this before – see Box 1.]
5 Carry out the experiment and perform the tests
deemed necessary.
6 Record your results.
Follow-up discussion
After the enquiry, pupils were led to discuss the
following questions:
l Could your system perform the functions of the
kidneys? Why?
l How could you apply your design to clinical
use? What technical problems would you expect
to encounter?
Post-activity discussion
After the discussion, pupils were introduced to the
use of dialysis as a treatment method. The principles
of the two forms of dialysis, haemodialysis and
peritoneal dialysis, were explained so that pupils
A problem-solving approach to STS
BOX 1
Test for the presence of urea in a
solution sample
Ten drops of the sample is placed in a test
tube. Five drops of bromothymol blue (yellow
in acidic medium) are then added, followed by
five drops of 2% urease. If the sample contains
urea, it will be broken down into ammonia,
which will turn bromothymol blue from yellow
to blue.
(SAFETY: Urease, like other enzymes, may
cause allergic reactions in some people.
Bromothymol blue, and the small amount of
ammonia produced in the solution mixture, may
cause irritation. Hence, care should be taken to
avoid contact with eyes, skin and clothes when
handling the above chemicals. Pupils should
wear safety goggles. Hands should be washed
thoroughly after handling. Adequate
ventilation is needed to avoid breathing
vapours of bromothymol blue and ammonia
solution. Any spills should be mopped up with
inert material immediately.)
could compare them with the set-ups they had
designed. Using information provided on the
website of the International Society for Peritoneal
Dialysis (see websites), pupils were guided to trace
the development of peritoneal dialysis, leading to its
establishment as a treatment option to haemodialysis.
This was to enable pupils to appreciate the painstaking
process scientists and technologists carry out in
their continuous quest to provide better solutions
to this chronic health problem. Pupils were also led
to consider the limitations of dialysis as an option
to kidney transplant and why there were so few
transplants compared with the number of patients
on the waiting list. They were then encouraged to
consider various possible ways of increasing the
number of potential donors, and the legal, ethical
and educational implications of different options.
Evaluation
The approach described in the previous section
was designed to introduce pupils to the application
of scientific principles in technology and how it
impacts on society. Through the problem-solving
activity, pupils were actively engaged in developing
solutions to the problem by applying what was
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A problem-solving approach to STS
Figure 2 A set-up for dialysis designed by pupils
with ‘blood’ inside the Visking tubing and dialysate
outside.
learnt in previous lessons. They found this activity
interesting yet challenging. In designing their setups (an example is shown in Figure 2), pupils had
to draw on knowledge about the composition of
blood, functions of the kidney as an excretory and
osmoregulatory organ, the principles of diffusion
and osmosis, and the concept of semi-permeable
membrane.
They also needed to draw on the dialysis
experiment they had carried out previously, using
Visking tubing to separate starch from glucose.
Hence, an added value to this activity is to enable
the teacher to check pupils’ understandings of these
aspects. As a result, a number of misconceptions
were identified during the activity. For instance,
some pupils erroneously added starch to their
‘blood’ sample, thinking that blood contains starch.
Some appeared doubtful as to whether proteins were
present in blood, with the understanding that proteins
could not be absorbed through the gut. Nearly all
pupils used distilled water as the dialysate, believing
this was most effective in extracting wastes from the
‘blood’. When pupils were asked to predict whether
their blood sample would increase or decrease in
weight after the treatment process, nearly all said
that it would lose weight because of the movement
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of solutes out of the Visking tubing. This showed
that many pupils did not realise that, in their case,
there was a net gain of water in the Visking tubing
because of osmosis; nor were they fully aware of the
osmoregulatory function of the kidney. There were a
lot of ‘aha’ responses when they came to realise the
problem of using distilled water as the dialysate. At
this point, they began to see the need to add essential
solutes such as glucose and salts to the dialysate to
draw out excessive water from the ‘blood’ and avoid
loss of these essential substances during dialysis.
At the end of the lesson, I administered a
questionnaire to the pupils to elicit their perceptions
about the lesson. They were asked to indicate their
agreement with a number of statements on a fivepoint Likert scale, ranging from ‘strongly agree’
(5) to ‘strongly disagree’ (1). In general, pupils
agreed quite strongly that the lesson increased
their understanding of osmosis (mean = 3.81), the
composition of blood (mean = 4.11) and the functions
of the kidney (mean = 4.04). The lesson also helped
them understand how dialysis could help patients
filter out unwanted materials (mean = 3.93). Aside
from conceptual understanding, the lesson was also
effective in achieving certain affective outcomes;
for instance, pupils became more aware of the
importance of the kidneys to bodily health (mean
= 4.12), showed more concern with protecting their
own kidneys (mean = 4.14) and valued their health
to a greater extent (mean = 4.16). Pupils seemed to
become more willing to donate kidneys after death
(mean = 3.69). Yet, the moderate mean value of
agreement relative to other statements implies that it
is difficult to change pupils’ attitudes towards organ
donation, which is perhaps deeply rooted in societal
culture.
Because of time constraints, there was only
limited discussion toward the end of the lesson on
the evolution of dialysis, though pupils were eager
to listen. With hindsight, this part could be treated as
extended project work. Pupils could be asked to find
out the answers to the following questions:
l What prompted scientists to develop peritoneal
dialysis as an alternative to haemodialysis?
l What were the difficulties encountered by
scientists in researching into peritoneal dialysis
and how were they overcome?
l What were the milestones or turning points in the
development of peritoneal dialysis?
l Can you distinguish between the roles played by
scientists and technologists in developing viable
systems for peritoneal dialysis?
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A problem-solving approach to STS
l What are the advantages and disadvantages
of peritoneal dialysis as compared with
haemodialysis?
l What are the limitations of dialysis as a longterm treatment method? What are the functions
of the kidneys that cannot be replaced by this
kind of treatment?
l What are the implications of dialysis for the
health-care system and society as a whole?
l What future developments do you predict will
occur in the continuous evolution of treatment
methods for kidney failure?
famines?’ and ‘How can we recycle domestic wastes
in agricultural or other man-made ecosystems?’ In
the first example, pupils could be asked to suggest
food rations for relieving hunger or malnutrition. To
do this, they need not only to apply knowledge about
nutrition but also to take into account budgetary
and logistical constraints in sending food to faminestricken areas. From this, pupils could enquire into
more long-term solutions to resolve the problem
of starvation, from both scientific and political and
socio-economic perspectives. In the second example,
pupils could experiment with composting and
laboratory models of wetland ecosystems as a means
to recycle solid and liquid wastes, and consider the
technological and environmental implications of
large-scale adoption of these methods. The process
pupils go through in this type of activity mirrors
that undertaken by scientists and technologists in
solving real-life problems. With pupils’ personal
involvement in these activities, it is easier for them to
develop a sense of ownership of the problem-solving
process typical of science and technology. This
problem-solving approach, coupled with follow-up
discussion on the implications of possible solutions,
could serve as an effective vehicle to enhance pupils’
understanding of the interactions between science,
technology and society.
Summary
Teaching of STS can go beyond analysing data,
discussing the socio-economic, environmental or
ethical implications of scientific and technological
developments, or debating controversial issues.
Teachers could engage pupils in solving genuine
human problems through the application of scientific
knowledge, hence prompting them to think more
deeply about the issues. This short article suggests
how this could be done in the case of treating
kidney failure. There are other problems relevant
to secondary science curricula to which a similar
approach could be applied, such as ‘What kinds of
food could be delivered to areas devastated by wars or
References
Baxter (2006) Kidney disease. Available at:
http://www.baxter.com/conditions/sub/renal_failure.html
(visited: February 2006).
Curriculum Development Council (2002a) Biology
curriculum guide (Secondary 4–5). Hong Kong SAR:
Printing Department. Available at: http://cd1.emb.hkedcity.
net/cd/science/en/syllabuses/biology/synopses/s4-5bio_
e.pdf
Curriculum Development Council (2002b) Physics
curriculum guide (Secondary 4–5). Hong Kong SAR:
Printing Department. Available at: http://cd1.emb.hkedcity.
net/cd/science/en/syllabuses/physics/synopses/phy_
cg2002e.pdf
DfEE/QCA (1999) Science: The National Curriculum for
England. London: The Stationery Office.
National Research Council (1996) National Science
Education Standards. Washington, DC: National Academic
Press.
Ziman, J. (1980) Teaching and learning about science and
society. New York: Cambridge University Press.
Website
International Society for Peritoneal Dialysis (for the
emergence of peritoneal dialysis): http://www.ispd.org/
history/genesis.php3 (visited: January 2005).
Yeung Chung Lee is a science lecturer at the Hong Kong Institute of Education, Hong Kong SAR, China.
Email: [email protected]
School Science Review, March 2006, 87(320)
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A problem-solving approach to STS
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