Why can physics be difficult to learn… and challenging to teach?

1. Why can physics be difficult to learn… and challenging to teach? Phil Scott Centre for Studies in Science and Mathematics Education, University of Leeds, UK. Fysikermøtet 200511 - 14 August 2005   Rica Brakanes Hotel, Ulvik i Hardanger.

2. Physics: frightful but fun… Angell, Guttersrud, Henriksen, Isnes (2004) Science Education ‘A general feature of physics pupils’ descriptions of their subject is that physics is regarded as difficult and with a high workload, but also interesting’. ‘All pupils (grade 12) agree to a great extent that physics is difficult’ ‘From our data it appears that physics is different from other school subjects (notably English and social science) in that it has a higher workload and a faster progression and is more conceptually demanding’.

3. What is involved in learning physics? • Learning physics involves developing a new way of talking and thinking about the natural world: drawing on specific concepts, theories, laws, mathematical tools, conventions. • This is a way of talking and thinking which has been developed and validated by the scientific community • It is a way of talking and thinking which must be consistent with observations and measurements of the physical world.

4. Everyday social language (Spontaneous concepts) …Vygotsky Scientific social language (Scientific concepts) What is involved in learning physics?

5. Why can learning physics be so: DIFFICULT?!

6. Everyday view: The ball falls because you let go of it, and it’s heavy. Scientific, physics, view The ball falls because of the gravitational pull of the Earth. Why does the ball fall?

7. Falling • Conceptual tools: not ‘heaviness’ of the object…but the concept of ‘gravity’ • Basic assumptions about the nature of the world (ontological demand): not a contact force…but action at a distance, ‘the pull of the Earth’ • Nature of knowledge (epistemological demand): not a ‘one-off’…but a generalisable explanation: falling, tides, planetary orbits…

8. Learning physics • …involves developing a new way of talking and thinking about the natural world • …always occurs against a backdrop of everyday ways of talking and thinking • …everyday ways of thinking are referred to as ‘alternative conceptions’!

9. BIG and SMALL learning demands • Different areas of physics make different demands • Where the learning demand is BIG physics can be difficult to learn and tough to teach • Where the learning demand is SMALL the physics seems like ‘common sense’. Leach and Scott (2002) Studies in Science Education Designing and evaluating science teaching sequences

10. Learning demand: between the particles • What lies between the air particles?

11. 1. And what is in between those particles? Researcher: And what is in between those particles? Student: Hmm……..space? Researcher: Tell me more about that. Student: Well… there isn’t really space because everything’s made up of something. You can’t just have something exists. Everything has pieces to it so it probably couldn’t be space. It could be….smaller particles? Cos, there couldn’t be nothing…so there’s probably just ones that can move around. Smaller ones.

12. 2. What is in that area between the particles? Researcher: What is in that area between the particles? Student: Erm….probably, as I said before…probably either smaller ones or…. erm….erm…energy? Researcher: Smaller what? Student: Smaller particles. Researcher: And how are those particles different? Student: They’re probably from a different substance, since air’s made up of different chemicals. Erm….the particles probably change…vary….. with the substance that it pertains to.

13. 3. And what’s in between the smaller particles? Researcher: And what’s in between the smaller particles? Student: Well….it couldn’t be nothing. I could guess that there are probably smaller ones…. cos…erm….I’d love to say air but this is air. So…it would be….within air. You can’t have nothing. So you’d have the smaller pieces. Researcher: And why can’t you have nothing? Student: Cos I don’t think that there is such a thing as nothing. Because even air which most people think is nothing….is made up of nothing…is just space…empty space. It has pieces to it as well.

14. Learning about special relativity Posner, Strike, Hewson and Gertzog (1982) Science Education Learning occurs if a new idea is both intelligible and plausible ‘One source of difficulty in learning special relativity stems from its lack of initial plausibility to physics students’.

15. How can two clocks read different times? Student: I mean how could they (the clocks) change? Time only goes at one rate, right? Student: Yeah, I mean, absolute time, it just seems to go on at a certain rate everywhere. It just seems natural that it’s constant everywhere. I mean, even though you see these results

16. Shrinking rods Student: I see them as being – as changing their length, or changing their time. But I can’t talk to the person who’s moving at the same velocity as the stick and the clock. He’s telling me they don’t change…I feel they haven’t changed, but the way I’m looking at them has changed…I guess I’m allowing for the fact that the person who’s seeing things at rest, who has his clock at rest, his metre stick at rest, has [pause] a little more right to say what is really happening to the sticks. Student: …the fact that it’s moving makes it appear to me as if it were foreshortened.

17. Feynman: on physics learning …there is this possibility: after I tell you something, you just can’t believe it. You can’t accept it. You don’t like it. It’s a problem that physicists have learned to deal with: they’ve learned to realise that whether they like a theory is not the essential question. Rather it is whether or not the theory gives predictions that agree with experiment. The theory of QED describes nature as absurd from the point of view of common sense. And it agrees fully with experiment. So I hope you can accept Nature as she is…absurd. Richard Feynman (1985) QED The strange theory of light and matter

18. Students’ everyday ideas • Air is weightless…or has negative weight • Heat is a kind of substance • Matter disappears during dissolving • Particles (molecules) expand on heating • Light travels further in the dark • We see things through light leaving our eyes • Energy gets used up • A force is needed to sustain steady motion • Things fall because they are heavy

19. Students’ alternative frameworks: Pfundt and Duit, 1991:Numbers of published papers.

20. An approach to planning physics teaching • Identify the key physics concepts to be taught • Consider the nature of students’ existing thinking in this area • Analyse the differences between the physics way of knowing and the students’ existing thinking: specify the learning demand • Devise teaching approaches to address the learning demand.

21. Simple electric circuits • Year 7 pupils (age 11-12 years) • No tuition in high school on electric circuits

24. Where does the ‘electricity’ come from? Students’ thinking: ‘The electricity flows out of the battery when the circuit is complete’ Physics view:The electric charges originate in the circuit. When the circuit is completed the charges start flowing in all parts of the circuit simultaneously.

25. The learning demand From point to point… • the circuit is initially empty and fills with a ‘substance-like material’ that eventually reaches the bulb and causes it to light. • Students use a ‘linear causal’ pattern of reasoning

26. The learning demand To all at once… • When the circuit is completed the charges are set in motion in all parts simultaneously • Students need to use ‘cyclic causal’ reasoning in which causes and effects co-occur. Perkins and Grotzer (2005) ‘Dimensions of Causal Understanding’ Studies in Science Education

27. What to do about it? • The BIG circuit! • The ROPE loop analogy

28. Key questions Battery In this circuit, the bulb is lit. Read each of the statements below about what is happening in the battery. For each statement, put a tick in one box to show if you think it is correct or incorrect.

29. Institute of Physics: Supporting Physics Teaching 11-14 • IOP sponsored • to support non-specialists in teaching physics at grades 7-9. • to strengthen their confidence, understanding and competence in physics teaching. • CD ROM based

30. What do you need to know? • The physics ‘story’ • Teaching and learning ‘challenges’ - pupil starting points - the nature of the learning demand in different topic areas • Teaching approaches - demos/practical activities - analogies/explanations/anecdotes

31. Structure of the SPT materials

32. And Einstein… A human being is a part of a whole, called by us ‘universe’, a part limited in time and space. He experiences himself, his thoughts and feelings as something separated from the rest... a kind of optical delusion of his consciousness. This delusion is a kind of prison for us, restricting us to our personal desires and to affection for a few persons nearest to us. Our task must be to free ourselves from this prison by widening our circle of compassion to embrace all living creatures and the whole of nature in its beauty.

33. Physics learning …as: breaking free from ‘everyday thinking’…

34. Physics teaching …as: working the GAP between ‘everyday’ and ‘physics’ thinking