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Our students need to realise that children do not come to
science as 'blank slates to be written on'
or as ‘empty vessels to be filled’. They have
ideas about why things happen. These naïve ideas are likely
to differ from the accepted scientific view, and may remain
uninfluenced, if our teaching ignores them
and/or the students do not actively and
intellectually become involved in the investigation itself.
The first part of this unit, ideas and evidence, explored
the nature of the scientific process, summed up by ideas
and evidence, or guesswork and checkwork.
Although scientific ideas are products of our imagination
(or at least the imagination of scientists who thought them
up), they do have to stand up to rigorous testing. The
second part of this unit investigative skills
examines how we can help intending teachers to cope with the
experimental and investigative side to
science, and covers, amongst others, the idea of making fair
tests.
Personal elicitation
These questions can be used to generate discussion
amongst trainee teachers:
1) Children left some seedlings to grow in a warm dark
cupboard, and others on a cool window sill. They watered
them both. The plants on the windowsill grew better than
those in the cupboard. What does this tell you about:
(a) the effect of light and warmth on growing seedlings and
(b) about carrying out a scientific investigation?
2) Some children were testing a range of cars to see
which went the furthest over the carpet. To make the
experiment fair the children took turns in pushing
the cars. Comment on this view of a ‘fair test’.
3) “We did the investigation three times to make it
fair?” Comment on this pupil’s view.
Misconceptions identified
Intending teachers need to understand some of the
problems faced by children as they undertake investigations.
Primary teachers will need to establish the ground rules,
but secondary teachers need to know the misconceptions that
pupils may still retain as they enter their secondary
education.
Question 1 above illustrates two problems children
often face in investigations:
- The need to decide what
is meant by ‘better’?
- The need to change only one variable at a time.
Have the plants in the window grown better? They look
greener and more healthy, but the ones in the cupboard are
taller, but very yellow. If ‘better’ means taller then
the cupboard wins! (In experiments with plant growth
investigations should always start with growing plants that
are as similar as possible - many investigations start with
seeds so the two processes of germination and onward growth
become confused - for more discussion see the units in
Subject Knowledge - science 2).
Many pupils will claim that the experiment shows that the
plants need light to grow well, but is it the extra
light or the cooler conditions that have caused
the window plants to look healthy?
Most intending teachers will see this as a problem of
variables - you must only change one thing at a time if you
want to pinpoint cause and effect. If you think it is light
levels that affect a plant's growth, then place both plants
by the window, but cover one in clear plastic, and the other
in dark plastic. The only difference is light level. If,
however, you think that warmth helps a plant, place them
both in the dark (covered in black plastic), but one is put
in a warm cupboard. (Or both can have light, with only one
kept warm.)
Goldsworthy & Feasey (1994) have developed an
approach that ensures that children:
- distinguish input or independent variables (what
you can change - the light levels, the warmth. . .)
from the output or dependent variables (what you
observe or measure - the number of leaves the plant
has, the colour of the leaves, the height . . .)
- only change one variable at a time (either light
level or temperature, but not both at once)
- identify the question they are asking (eg. “Is
the number of leaves that grow on a plant affected
by the light level?”)
- know that the test is fair (everything is the same
for both plants except the light level)
- are able to record their results in a table or on
a graph
- draw a conclusion that relates to the question
they asked
For further details of their approach see download 2.1
Primary Investigations. Secondary trainee teachers
should also be aware of this approach - their Y7 pupils are
likely to have had experience of investigations in this
format.
Question 2 above relates to the idea of making a test
fair. Young children are likely to see this a taking
turns, rather than controlling variables. It can start in
the reception class using the exaggerated error approach
- when you ask children to see which car goes furthest, push
one very gently and the other very hard. The children will
cry out 'not fair' and start their progress on the road to
understanding that you must keep everything the same (fair)
except the one thing you are testing (type of car).
Investigations with two variables
As pupils enter the secondary school they will begin to
do investigations where two variables are manipulated. Many
investigations go wrong at this stage - see download 2c
Question 3 above, illustrates another misconception about
‘being fair’. ‘Fairness’ relates to variables, but
taking multiple readings relates to reliability. If all your
readings cluster neatly you can be sure that the result is reliable.
If they scatter widely there is likely to be another
variable at work that you have not controlled properly, and
you cannot rely on your results. (It is a matter of
judgement to decide whether a given set of results is
sufficiently reliable for your purposes.)
Investigations with multiple variables
When scientists do observational experiments on complex
systems that they cannot manipulate, such as the behaviour
of animals in the wild, complex statistical methods are
required to determine if a particular observed difference
could have happened by chance or whether it might be 'real'.
These are beyond the scope of primary science, but need to
be explored when evidence is presented. Usually the
statistical methods will allow an estimate to be made of the
probability of an observed difference occurring by chance.
If the probability of chance is more than 1 in 20 (0.05)
then the difference is not usually accepted as real.
Question 3 above also needs attention, and is
discussed in download 2c
Types of practical activity in science
Practical work has many uses in science - it is
important that your trainee teachers identify the purpose
every time they plan practical activities with children. It
is also always important that the teacher does a risk
assessment prior to any activity so that the risk can be
minimised and the pupils know what to do if anything goes
wrong. Pupils should also be encouraged to be aware of
safety issues - although it remains the teacher’s
responsibility. Anyway, here five of the most important
reasons why we ask pupils to do practical work:
1. Gaining experiences
- describing, sorting, classifying (similarities and
differences)
- starting point for investigations, questions,
predictions, hypotheses
Before children can begin to think about why something
happens they must have experienced it. Much of our work at
Key Stage 1 will be in this category, eg children's first
experience 'playing' with magnets.
2. Illustrations of scientific ideas
- give instructions of what to do
- illustrate concept or process for discussion
When you have challenged children's ideas about why
something happens you may want them to test out this new
idea you are giving them in a controlled environment. For
example, asking them to feel their heart beat after exercise
suggests a link between blood flow and supplying food and
air to the muscles.
3. Making observations
- opportunity for use of knowledge and understanding
Observations cannot be naïve. What we observe is always
a combination of the ideas stored in our brains, and the
sense data we receive. Each child will observe only what
they are able to make sense of. Asking children to 'observe'
carefully is a good way of finding out what ideas they do
have in their minds, eg asking them to observe and draw
their shadows.
4. Basic skills
- selecting or using equipment
- communication skills (eg writing, drawing, making
and interpreting graphs)
- techniques (eg measuring force, temperature etc)
Sometimes it is important to teach children how to use a
particular technique or piece of equipment. It is much
better to combine such introductions with an investigation,
but the newness of the task means that you want the
investigation to be simple. An example is learning to use a
thermometer by leaving it around in different places and
recording 'room temperature', or feeling the temperature of
cups of water before and after mixing or sharing them. It is
important, even here, that pupils should try to understand
the question and have contributed to the purpose of
measuring temperature, or at least predicted the
temperatures about to be measured.
5. Investigations
- arise from observations and discussions - pupils
should understand and ‘own’ the discussion.
- encourage pupils to think, plan, carry out and
interpret
Investigations are the ultimate aim of children's
practical work in school, and all trainee teachers should
undertake an investigation , and attempt to assess their
success as part of the process of coming to terms with what
we are asking pupils to do in school. It is vital that
pupils/students do not see the purpose of an investigation
as being to gain high marks in an assessment.- clearly an
assessment should be serious, but the marks ore an outcome
of how the investigation is done and communicated NOT why an
investigation is done.
Teaching scientific enquiry 
The Science Enhancement Programme has developed some
important resource material which our intending teachers can
make use of. This is an extract from http://www.sep.org.uk/proj_skees.html
“Different kinds of enquiry place different emphasis on
various skills and processes, so using a wider variety of
enquiries offers new opportunities and contexts for teaching
and learning scientific skills and procedures. The AKSIS
project generated a range of strategies for developing
specific scientific skills and processes, and these
strategies will be advanced further in the SKEES project.
The project is taking place in three phases:
- Development of scientific enquiries
- Trial of scientific enquiries in collaboration with
teachers
- Development of exemplification materials and trialling
with a wider sample
The work is being done at Kings - follow this link: http://www.kcl.ac.uk/education/skees.html
Anna Cleaves and Rob Toplis have written a paper for School Science Review (a link will appear here on publication) entitled: "Assessment of Practical and Enquiry Skills: lessons to be learnt from pupils’ views"
They report research into the views of pupils from nine state-maintained secondary schools about assessed investigative work at Key Stage 4 (14 to 16 year-olds) in the English National Curriculum. It presents a discussion of pupils’ views about the role of the teacher, the timing of investigations in relation to curriculum content, time allowances and apparatus provided.
They conclude that there is little benefit in being trained to do a limited range of investigations at Key Stage 4. This situation seems to have arisen from a culture of high stakes assessment, where a difference between a GCSE grade D and a grade C is critical for comparing school with school and has had the widespread effect of conflating the teaching and assessment of investigations.
They support a less prescriptive assessment policy that relies less on a performance model for assessment and more on teachers’ professional judgement and decision-making. Such a policy would improve the scope and variety of investigative work.
Teachers may consider, in the light of the research they reported, that GCSE programmes starting in 2006 are an opportunity for reclaiming
investigation for science learning by teaching science
through investigation, and not divorced from it, thereby avoiding the confusions and lack of motivation depicted by the pupils who have to fulfil the Exam board criteria of 'standard' whole investigations.
The research is published in full in Toplis and Cleaves (2006)
Research into children's ideas has mainly concentrated on
strands two, three and four of the National Curriculum. The
best account of children's views about the nature of science
and how science happens is in Driver et al (1996). Research
suggests that children see no point in scientists doing
experiments if they already suspect what might happen. Most
children have a 'eureka' view of science. A scientist does
an experiment, not knowing what might happen and suddenly
out plops a discovery at the end.
Driver suggests that it is not until pupils sit their
GCSE that they truly begin to see experiments as testing
ideas - that scientists do know what they think (and
hope!) will happen, because they are testing an idea that
they are trying to believe in.
- Goldsworthy A & Feasey R (1997) Making Sense of
Primary Science Investigations Revised Edition Revised
By Stuart Ball. Hatfield: ASE isbn 0863572820
- QCA/DfEE (1988) Science: A Scheme of Work for Key
Stages 1 and 2 London: QCA (See Science Teachers'
Guide Table C pp16-17 - Experimental and
Investigative Science from Years 1 to 6)
- Ross K (1998) Brenda Grapples with the Properties
of a Mern in Littledyke M & Huxford L (eds)
(1998) Teaching the Primary Curriculum for
Constructive Learning London: David Fulton
- http://www.sep.org.uk/proj_skees.html
- http://www.kcl.ac.uk/education/skees.htm
- Toplis and Cleaves (2006) Science Investigations: the views of 14 to 16 year old pupils. Research in Science and Technological Education 24 (1): 69-84
Downloads in this Unit:
Section Developed by:
Keith Ross, University of Gloucestershire
March 2006
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