The Association for Science Education

K1.1 Ideas and Evidence


This article explores the conceptual barriers to understanding the nature of science or 'how science works'. In general many scientists and science educators do not have a clearly articulated view on the subject and it remains a disputed field. It seems clear that 'doing science' is an activity that all humans engege in to some extent and that it requires curiosity, intellectual honesty and a search for understanding, explanation and application in the contexts of observation, experiment and language.

This is one of 17articles whose main aim is to support the processes of teaching/learning between the science education tutor and the trainee science teachers with a focus on “teachers’ knowledge and understanding”. During a primary or secondary BEd, PGCE or GTP we hope that those learning to become science teachers will be able to challenge their own understanding of science and scientific concepts. Unit K0 specifically explores general issues relating to all the knowledge units - to the learning of science.

Standards: This unit specifically addresses Q14 but, appropriately used can contribute to and provide evidence of competence for many others of the standards especially Q4,6,7,8,18, 22 and 25.

Key words: Nature of science, Investigation, Explanation, Theory, Practice.


1.0 Introduction
2.0 The conceptual barriers to understanding the Nature of science
2.1 Personal elicitation
2.2 Guesswork and Checkwork
2.3 Steps in forming an explanation and developing a scientific concept
2.4 Images of a scientist (question 4)
3.0 Implications for teaching
3.1 The Science Enhancement Programme (SEP)
3.2 First -hand evidence and the role of language in developing ideas
4.0 Progression in children's ideas about the nature of science
5.0 Useful References

(NB This unit is written from an unashamedly constructivist viewpoint. You may of course wish to emphasise, to those with whom you discuss the nature of science, particular flavours of constructivism, to be critical of the framework used here or provide alternative or additional perspectives – but as tutors, or students, we must own our own ‘story of science’.)

1.0 Introduction

Children do not come to science as 'blank slates to be written on'. 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. This Ideas and Evidence unit explores the way science teachers can help children construct an understanding of their environment that accords with current scientific ideas. This is achieved through the construction of new scientific ideas or theories.

An interesting and provocative article by James Williams (Sussex) that outlines issues relating to the nature of science and trainees' understandings is provided in Download K1.1_1.0a 'How does science really work?'

Although these 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 and critical evaluation from those who use the ideas in their own work, often in other fields of study, be they scientists, technologists, teachers or students (other scientists may have different ideas too). The Investigative Skills unit examines the experimental and investigative side to science, and covers, amongst other things, the idea of making fair tests. 

The Science Enhancement Programme (SEP) has developed some important and very useful materials to help teachers develop their approaches to teaching this section of the science curriculum, and this unit makes full reference to this material.

2.0 The conceptual barriers to understanding the Nature of science

2.1 Personal elicitation
Trainees, like pupils in school, need to be challenged with questions that elicit their personal ideas about the nature of science so any misconceptions can be addressed. The questions that follow are based on areas that have confused children and students alike. Further details can be found in the PowerPoint presentation, download 2.1a Look at the ‘notes’ section for information on how to use the presentation.

These four questions can be posed to students to begin the process of understanding the Ideas and Evidence strand of the National Curriculum, and more generally to understand how science works. Discussion of these two questions follows in section 2.2 Guesswork and Checkwork.

1) Which model of science do you agree with and why?

Science as Objective Science as Human endeavour to understand and control the physical world
Capable of yielding ultimate truths Producing knowledge which is tentative, always subject to challenge by further evidence
Proving things Creating new, testable, ideas
Having a defined and unique subject matter Building upon, but not accepting uncritically, previous knowledge and understanding
Having unique methods A social enterprise whose conclusions are often subject to social acceptability
The same for everyone Constructed in the minds of individuals but developed in a social context via language and critical debate
Being value free Constrained by values

 2) If you wrap a block of ice cream up in a blanket, will it melt faster, slower or at the same rate as the unwrapped one left in the same room at room temperature? 

3) What is the function of the wax in a candle?

4) Get pupils in your class to “Draw a scientist”

Download K1.1_2.1a 'Ideas and Evidence' contains some suggested workshop activities for trainee teachers to undertake following their first experience in school to consolidate their understanding of the Ideas and Evidence strand.
Download K1.1_2.1b 'Workshop Ideas' (Presentation of the initial elicitation questions and introduction to the topic.)

2.2 Guesswork and Checkwork
Karl Popper (1959) and later philosophers realised that Science progresses by people having ideas (Popper’s Conjectures, Medawar’s (1969) guesswork), which then have to be tested against ‘reality’ (Popper’s Refutations and Medawar’s checkwork). This is reflected in the right hand column in the table in question 1 above. [NB Conjectures/guesses are not unconstrained - they are ‘educated’ guesses based on previous experience (or trusted information sources). One problem is that when we have a reasonable theory that seems to explain something, we no longer tend to ask questions or consider it worthwhile to do experiments. Perhaps teachers should more often encourage students to ask questions and test their answers? This should avoid the unkind - although too often true - caricature of school science as ‘telling children the answers to lots of questions that the children have never even thought of’!]

In the ice-cream question (q.2) above, many children (and adults) may have an idea that blankets are intrinsically warm, so the ice-cream will melt faster if wrapped in a blanket. This is the conjecture or guess. It is an idea or theory which we then have to test against ‘reality’. When the experiment is performed many are surprised that the wrapped ice-cream stays frozen longer than the unwrapped one. This result means that they have to re-visit their theory about blankets being warm. Perhaps they will recall that beds are not warm until a living person enters them. A new idea would be that the blanket is a barrier to the flow of thermal energy, so the heat generated by the body remains in the bed. It is not the blankets that are warm, but they are acting as a barrier. Thus in the case of the ice-cream, the heat from the room gets to the unwrapped one quicker than the one wrapped in a blanket.

This view of how science works has an exact parallel to constructivist ideas about teaching. Children make imaginative guesses to explain phenomena around them, and fair testing allows them to make consistent and valid tests to check if their ideas can be believed in. Scientific ideas have changed over the centuries, and are still changing today. What we tell children is our ‘best guess’, and we need to give them a flavour of both the creative guesswork and the rigorous checkwork that is at the heart of our scientific understanding. This unit has a focus on the ideas (guesswork), and the linked unit, Investigative Skills, deals with the testing (checkwork) of ideas.

See P1.6 History and philosophy of science and science education in the Professional Issues section of sci-tutors for more on this, and, for children’s ideas, see Professional Issues/Teaching/Misconceptions.

The problem in school is how to put over this picture of how science works, for, although science teaching in the UK is dominated by practical work, time restraints mean that many of the activities pupils do are tightly structured, rather like following a recipe. Chapter 1 in Teaching Secondary Science (Ross et al. 2004) has a section describing eight activities involving the process of rusting (pages 7-10). They are designed to help secondary trainees focus on the role played by practical work in science lessons, and they are asked to decide, for each activity:

  • Which of these are best in helping pupils to understand what happens during rusting? (pupils may, for example, think the iron ‘rots’ like wood - an idea we need to challenge.)
  • Which give a good picture of the process of being scientific? (guesswork followed by checkwork).
  • Which are unhelpful in both respects? (Perhaps because they are too complex, or are recipes that pupils can follow without thinking)

2.3 Steps in forming an explanation and developing a scientific concept

Pupils find problems with elicitation question No 3 (Para. 2.1) - What is the function of the wax of a candle? The more wax there is the longer the candle lasts. Wax drips down the side. It seems that the wax is retarding the flame - slowing the burning of the wick. A Y6 child said 'the wax is fireproof' See PowerPoint download in children's ideas unit.

How can we, as teachers, challenge this view, and show that burning is a constructive process where it is the wax which burns, joining with the air producing oxides? How can we persuade children that the wax is the fuel?

Download K1.1_2.3a 'What is the purpose of the wax in a candle?'

The act of challenging pupils’ naïve ideas and comparing them with those accepted by the scientific community not only helps children understand the nature of our world, but also helps them appreciate the way in which scientific progress is made.

2.4 Images of a scientist (question 4)

Somehow we need to convince our student teachers and they need to convince their pupils, that we are all scientists. The way we all learn about our environment is by guesswork followed by checkwork. Maybe not formally, nor rigorously, which is where the science teacher has a part to play. See slides 17-20 of download k1.1_2.1a Pupils' images of the scientist may be very narrow and stereotypical.

Download k1.1_2.4a is taken from the BEd Secondary course at the University of Lancaster and gets students to examine the way ideas about forces developed over historical time and can be applied to everyday activities and may help to broaden their view of science and scientists.

Download K1.1_2.4a 'Forces Assignment'

3.0 Implications for teaching 

3.1 The Science Enhancement Programme (SEP)
The work done by the Science Enhancement Programme for Key Stage 3 has implications for teaching about the nature of science at all ages.

Teaching about Ideas and Evidence in Science at Key Stage 3A project funded by the National Strategy and Science Enhancement Programme

The material is available on CD-ROM and includes examples of classroom activities with notes for teachers and pupil materials.

The materials have been collated by a team of science educators working in five Universities involved in initial teacher education.

Martin Braund - University of York
Sibel Erduran - formerly King’s College London, University of London
Shirley Simon - Institute of Education, University of Londo
nKeith Taber - University of Cambridge
Rob Tweats - Keele University

You need to visit the web pages and link to the whole project, but here is one quotation to whet the appetite:

At present, many pupils are learning science as isolated fragments of knowledge, and this does not allow them to appreciate how ideas come about, or how they may not always apply, or why they may not always lead to precise predictions. Pupils often see theories as facts, which have been proven, because science is often presented that way. If pupils could spend more time seeing how ideas develop, and how they change, they would better appreciate the nature of scientific knowledge, and the great cultural achievements of science.

3.2 First -hand evidence and the role of language in developing ideas
Children are more likely to make links between their existing naïve ideas and scientific ideas if teachers present ideas which are related to the children's experiences. So, to establish such links we need to encourage children to relate everything to their own experiences and to put forward their existing explanations. They are then allowed to test predictions against their existing and against the new (teacher presented) ideas. See paragraph 2.2 above for an example of this approach.

Investigations in science are the tool for rearranging their existing explanations into more generally accepted world views. When children are working in groups their ideas can be brought out into the open and verbalised - this verbal exploration allows their thinking to be tested.

Talking is essential to learning, and exploratory talk is needed for children to be 'in charge' of their learning. No college student will write an assignment straight into 'best', no politician will write their speech directly as the final version. This web-page was not written once and never amended. We all need to draft our ideas first - and the first draft is best done verbally. In school this will allow children to make sense of things - only then might it be sensible for them to try to make a written record.

We need, too, to be careful in our judgement of children’s ideas. Their use of a word does not indicate that they have a grasp of its public or scientific meaning. They may have the right concept but using the wrong word. For example, if a child says, 'A ton of feathers is lighter than a ton of lead', the statement is true if by 'lighter' the child means less dense, but false if they mean the reading on a weighing scales.

Several examples are needed to illustrate an idea because the existence of different meanings only comes to light when a range of situations are explored. For example, see how the meaning of the word animal changes with context:

No animals allowed in this shop.
We, like other mammals, feed our young on milk, and mammals are animals.

The implication is that a wide range of experiences is necessary to challenge children's ideas.

Ideas change as children become older (in the reception class humans are definitely not animals, by Y6 they are beginning to be so but by Y11 at the age of 16 humans are certainly classed as animals).

What can teachers do?
1) Accept that children's ideas can influence teaching.
2) Be aware of children's ideas on a topic.
3) Provide first hand experiences before discussing ideas.
4) Encourage children to express ideas and appreciate other views verbally.
5) Value new ideas by using them to solve problems and make sense of experiences.
6) Realise that communication is important.

4.0 Progression in children's ideas about the nature of science

Research into children's ideas has mainly concentrated on the conceptual side of the National Curriculum. An excellent 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 the purpose of 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. This is why medical trials are done 'double blind', ie half a population of people in a trial are given a 'placebo' with no drug in it, and neither the patient nor the doctors know who is taking the real drug. So if the effect is purely psychological, all the patients get better. If the doctors are allowed to know who has been given the drug, they may 'see' an improvement in the treated patients that is not really there.

When scientists do observational experiments on complex systems that they cannot manipulate (e.g. the behaviour of animals in the wild), complex statistical methods are required to determine if a particular observation could have happened by chance or whether it might be 'real'.

To begin with pupils need experiences. Much of the science we present to pupils in school, especially in the early years, provides them with new experiences, or examples of phenomena that they will find hard to distinguish in their real world (e.g. magnetism, electricity, growth of plants). It is only when they are aware of the phenomenon that can we begin to get them to think about ideas and explanations, causes and relationships.

The right hand column in the elicitation question no 1 in paragraph 1 above gives a provisional, negotiated view of scientific ideas - a view that scientific ideas develop and change, not only in the scientific community as a whole but in children as they experience more of the world.

At KS3 and 4 we need to help pupils assume the role of being a scientist within the constraints of the school laboratory. This process involves thinking and is not just practical. Pupils need to predict what will happen and only then test their ideas and expectations. A successful investigation needs purpose - something that the pupil can relate to and have empathy with. Investigations need to be seen as a part of the activity of the wider scientific community, not a way of getting marks at GCSE, however important that also has to be. The new orders for GCSE will help to bring back this sense of purpose into investigations and about how science works.

5.0 Useful References

  • NCC (1993) Teaching Science at Key Stages 1 and 2 York: National Curriculum Council
  • CCW (1992) Science - Starting with Children's Ideas Cardiff: Curriculum Council for Wales
  • Driver et al (1996) Young People's Images of Science Buckingham: Open University Press
  • Osborne, J., Erduran, S. and Simon, S (2006) Ideas, evidence and argument in science education. Education in Science pages14-15 Number 216 February 2006
  • Ross K (1998) Brenda Grapples with the Properties of a Mern in Littledyke M & Huxford L (eds) Teaching the Primary Curriculum for Constructive Learning London: David Fulton
  • Ross, K.A., Lakin L. and Callaghan P. (2004) Teaching Secondary Science - constructing meaning and developing understanding. Second Edition. London: David Fulton.
  • Ross, K.A., Lakin, L and Burch, G (2005) Science Issues and the National Curriculum CD-rom. Cheltenham: University of Gloucestershire
  • Sutton, C. (1992) Words, Science and Learning, Buckingham: Open University Press.
  • Teaching about Ideas and Evidence in Science at Key Stage 3 A project funded by Key Stage 3 National Strategy and Science Enhancement Programme

Other References

All the websites were accessed on 8 March 2006 

Section Developed by:
Keith Ross, University of Gloucestershire with support from Alan Goodwin and Aftab Gujral

Published: 31 Mar 2006, Last Updated: 12 Sep 2008