Transcript Slide 1
Teaching and learning about the nature of science: Implications for physics teaching
Dr. Jim Ryder School of Education University of Leeds, UK [email protected]
Outline
1. What is the Nature of Science?
2. Why teaching/learning about the Nature of Science?
3.
Students’ ideas about the Nature of Science/Physics 4. Implications for physics teaching
World Science
A way of examining and talking about the world
The Nature of Science
Examining and talking about Science (‘Knowledge about Science’)
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The Nature of Science
What are the purposes of scientific investigations?
How do scientists design investigations?
How do scientists assess the quality of data?
What is the nature of scientific explanations?
What are the limitations of science?
How does the scientific community work? (Internal sociology of science) How do scientists/science knowledge interact with social issues? (External sociology of science)
The scientific method?
• Observe phenomena • Develop question • Create hypothesis • Design experiment • Conduct experiment • Analyse data • Draw conclusions Based on: Windschitl (2004) Folk theories of ‘inquiry’: How preservice teachers reproduce the discourse and practices of an atheoretical scientific method. Journal of Research in Science Teaching, 41(5), p.481-512.
The scientific method?
“There is no such thing as ‘the scientific method’. A scientist uses a great variety of exploratory strategems, and although a scientist has a certain (…) way of doing about things that is more likely to bring success than the gropings of an amateur – he uses no procedure of discovery that can be logically scripted.” Medewar, P. (1984) The limits of science. Oxford University Press, p. 51.
Objective observations?
• Do we simply ‘observe’?
• We use theories/ideas to interpret what we see Standing on a hilltop at dawn two people are observing the eastern horizon. One says: ‘the Sun is rising above the horizon and travelling up into the sky. The other person says: ‘the Earth is turning, allowing us to see the Sun above the horizon’
Science Explanations
Science explanations are more than descriptions of phenomena/observations/data
DESCRIPTION
The Sun rises in the East A steaming hot cup of tea cools down In a simple circuit the bulb will light up when the switch is closed.
SCIENCE EXPLANATION
The Sun is at the centre of our Solar System. The Earth spins on its axis once every 24 hours.
Evaporation produces cooling because the most energetic particles leave the liquid.
When the switch is closed the charges in the wire form an electric current which transfers energy from the battery to the bulb.
Models of the atom
Characteristics of explanations in science Generalisable Simplifying Assumptions Predictive Power Abstract ideas Use of analogies particle theory of matter explains cooling through evaporation, solid-liquid-gas phase transitions, minimum temperature, expansion/contraction magnetic field lines in two dimensions; ignoring friction in dynamics; assuming a spherical Earth Particle theory of matter and minimum temperature; Bohr model of atom and chemical valency Electron orbits, electron clouds; Mendel’s theory of inheritance and ‘genes’, Light moving as a ‘wave’ through the ‘aether’, Maxwell’s vortices Mechanism particle theory of matter provides a mechanism for expansion of solids on heating
The role of chance and status in the development of physics knowledge - the discovery of the electron spin
I think that you [Goudsmit] and Uhlenbeck have been very lucky to get your spinning electron published and talked about before Pauli heard of it. It appears that more than a year ago Kronig believed in the spinning electron and worked out something; the first person he showed it to was Pauli. Pauli ridiculed the whole thing so much that the first person became also the last and no one else heard anything of it.
Letter by L.H. Thomas to Goudsmit, 25 March 1926 It is indeed very clever but of course has nothing to do with reality.
Pauli.
Outline
1. What is the Nature of Science?
2. Why teaching/learning about the Nature of Science?
3.
Students’ ideas about the Nature of Science/Physics 4. Implications for physics teaching
The aims of scientific literacy 1
‘… much of the scientific knowledge acquired at school is forgotten by adulthood. Rather, what is needed is a much better understanding of the practices, processes and limits of scientific knowledge. Developing such an understanding is essential if individuals are to be able to make personal decisions and to participate in the public debate about the moral and ethical dilemmas increasingly posed by scientific advances …’
The aims of scientific literacy 2
‘…what is important is not that citizens should be able to remember and recall solely a large body of scientific facts, but that they should understand how science works and how it is based on the analysis and interpretation of evidence. Crucially, citizens should be able to use their understanding of science, so that science can help rather than scare them’.
Scientific literacy should not be taken to mean the knowledge of a lot of science, but rather the understanding of how science really works.
Durant, j. (1994) What is scientific literacy?,
European Review, Scientific theories are guesses that haven’t been proved yet. After the theory is proven it will become a law.
Vol. 2, no. 1, 83-89.
Science and ‘real life’: Interactions with mobile phone technology
• Science concepts: e.g. source-receiver model of radiation, non/ionising radiation… • Technology: use of network of base stations, directivity of the beam… • Nature of Science: the need for a large sample in studies, difficulty of designing studies over a long period of time outside of the laboratory.
Science and ‘real life’: Interactions with mobile phone technology
The case of a parent who was convinced that moving her child away from a school sited near to a mobile phone mast was the cause of a dramatic improvement in her child’s health: ‘she’s a different child now – it’s all the proof I need to convince me there is a link between those wretched masts and the health of children’ (Burgess, 2004, p. 1).
School Science
Established knowledge Hard facts
Science in a Public Domain
Contested knowledge Complex, ‘real world’ contexts
Ready Made Science (Latour) Science in the Making
Outline
1. What is the Nature of Science?
2. Why teaching/learning about the Nature of Science?
3.
Students’ ideas about the Nature of Science/Physics
4. Implications for physics teaching
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In an experiment you should keep taking measurements until you get two values that are the same. That’s then the true value.
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If two scientists disagree about the interpretation of data from an investigation then one (or both!) of them must be incompetent or biased.
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Scientists are independent of government.
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Scientists should be able to tell us whether something is completely safe (e.g. using mobile phones).
Young people’s ideas about theories in science
‘If you set up a hypothesis not yet clearly proven, it is a theory. After the theory is proven it will become a law’ ‘It’s just a theory – they don’t know for sure’ ‘Theories are guesses that haven’t been proven yet’
Students’ understandings of the nature of scientific knowledge I
Level 1
• Knowledge directly reflects reality. • The goal of science is to invent things.
• Lack of distinction between the goal of understanding a phenomenon and producing a phenomenon. • Lack of distinction between theory and evidence. ‘An experiment is when you try it and see if it works’ The goal of science is: ‘to discover new things’; ‘to find new cures for diseases’ Carey, S., Evans, R., Honda, M., Jay, E., & Unger, C. (1989). 'an experiment is when you try and see if it works': A study of grade 7 students' understanding of the construction of scientific knowledge.
International Journal of Science Education, 11
, 514-529.
Students’ understandings of the nature of scientific knowledge II
Level 2
• Clear distinction between ideas and experiments.
• Inquiry is guided by particular ideas and questions.
• No recognition that the results of an experiment may lead to revision of an idea.
Scientists do experiments : ‘to test to see if their idea is right’
Students’ understandings of the nature of scientific knowledge III
Level 3
• The purpose of experiments is to test and explore ideas - if unexpected results appear the scientist will need to modify their idea. • Science is a cyclic, cumulative activity.
A scientist: ‘probably thinks up an idea, and then builds an experiment out of the idea, and if he’s right or wrong he keeps building up more questions to see, to find out even more stuff than he knows’ ‘He’d probably have to change his hypothesis a little to fit in with the new data’
Level 1 2 3 Key differentiations
No differentiation of ideas and evidence Simple differentiation of ideas and evidence Differentiation among theories, hypotheses and evidence
Nature of knowledge
True beliefs about what happens and what works Well tested hypotheses; generalisations about how or why something works
Process of enquiry
Making observations, doing tests, finding answers Simple hypothesis testing Well tested coherent theories (explanatory frameworks) Cycles of hypothesis testing that test and develop theories (Based on Carey and Wenk, 2006)
Outline
1. What is the Nature of Science?
2. Why teaching/learning about the Nature of Science?
3.
Students’ ideas about the Nature of Science/Physics
4. Implications for physics teaching
21
st
Century Science GCSE Course
We need a curriculum model for science that offers flexibility and genuine choice to cope with the diversity of students' interests and aspirations. The model we propose offers all students the chance to develop the scientific literacy that they need to play a full part in a modern democratic society where science and technology play a key role in shaping our lives - as active and informed citizens. In addition, for some students – perhaps a minority – we are producing courses which provide the first stages of their training as a scientist, or for a career that involves science. http://www.21stcenturyscience.org/home/index.asp
Curriculum purposes
1.
Science education as preparation for advanced study in science 2.
Science education to support people’s engagement with science as citizens
21
st
Century Science
Twenty First Century Science offers three different GCSE science courses for different purposes.
Science: scientific literacy for all
For all Key Stage 4 students (age 14 to 16), taking 10% of their curriculum time and leading to one GCSE grade.
Additional science
Alongside core Science, young people can opt for one of two Additional Science courses, also taking 10% of curriculum time and leading to one GCSE grade: - Additional Science - Additional Applied
21st Century Science GCSE Course
• Module topics (e.g. Air Quality, Keeping Healthy, Food Matters) • Scientific Explanations • Ideas about Science (i.e. the ‘nature of science’)
Teachers’ experiences of 21CS
We notice that the enthusiasm, the engagement level is going up, so they’re becoming more interested in science. We are having pupils who are staying behind to ask questions in certain groups which wasn’t happening before Well with our kids in particular, they love discussion and (…) they are very good at doing it. What I would think our teachers need is strategies on how to actually do discussions (…) a lot of teachers are too scared to kind of let go and just let the kids talk about stuff, and then sort of bring them back together to find out what they think.
Teachers’ experiences of 21CS
There are two things that have happened this year that have not happened before. The first thing is that lessons have been completely taken over by the students asking the questions. The second, and by far the best, thing is that not once, not on a single occasion, not ever this year have I had to answer the question ‘why do we have to learn this?’ (Teacher quoted in IOP Education newsletter Feb 2008)
Teachers’ experiences of 21CS Should Physics be more elitist?
Physics is a subject that requires certain intellectual skills that the majority of the population do not have… there persists a strange notion that anyone and everyone should study… physics … such a notion is patently absurd.
(Headteacher, Physics World, 2004, in an exchange with Jonathan Osbourne)
Leeds study
240 teachers; written questionnaire; open responses End of first run through 2 year courses for 14-16 year olds 38% improved student motivation 30% improved student achievement 45% challenge of managing changes to assessment 29% difficulties with resourcing 14% difficulties with teaching nature of science 12% difficulties ‘finding’ practical work 19% ‘dumbing down’ of science curriculum
Students’ experiences of 21CS
It is a quite up to date modern course that teaches you useful things that you can relate to like real life situations, so you could actually use it in real life.
You remember more out of these lessons because it is more relevant to you now, instead of just you go past and see a sign for like genetic babies and you would say ‘oh I know about that’
Challenges and opportunities ahead
• The curriculum is already overcrowded. How can we possibly teach more in the science curriculum?
• Why change the science curriculum yet again?
• All this is new to me. How do I teach the nature of science?
• I enjoy teaching about the nature of science but many of my students resent it because it isn't on the exam.
• All this ‘discussion’ about socio-scientific issues is going to ‘turn off’ the students who would normally choose to study physics further, and become the physicists of the future