1. Conceptual structuring and critical faculty in physics education. Research examples at university level Laurence Viennot PRES Sorbonne Paris Cité, University Paris-Diderot, LDAR laurence.viennot@univ-paris-diderot.fr

2. Multiple objectives … Engage students with physics Simplify Help students construct a first idea of NOS: inquiry, reasoning Consistency as a goal (NOS), as a need (reasoning) (…) Develop critical stance in students

3. Oversimplification: Some intrinsic risks -Wish to show + belief that seeing is understanding -« Echo-explanation » : mirroring students’ common ways of reasoning - Ignoring some variables, phenomena : conceptual reduction - Ignoring some phenomena: uncontrolled generalisation - « All-or-nothing » approach - Denying de facto the validity of a law As a result: serious inconsistencies Viennot 2014

4. A student: Emergency blanket… aluminium (all agree) Some experiments Conclusion: With aluminium, you cannot protect against cold (no comment) *DVD Acad. of sciences (FR), of Technologies, DGESCO, 2010 Ignoring a phenomemon Uncontrolled generalisation Radiant process ignored Explicit inconsistency A model sequence * : how to protect against cold? Hot water Ice cube With aluminium we cannot protect against cold Ice cube melts first with aluminium at lower secondary school level

5. pOpO pOpO pOpO pOpO A hot air balloon …a total mass of… Whatever the temperature of the air in the balloon, its pressure will be the same as the surrounding air. (……….) …Show that to achieve the lift off…must be heated to about ….° C. A hot air balloon: A typical exercise* *For instance: Since the balloon is open to the atmosphere, the pressure in the balloon is the same as the pressure outside the balloon. D.C. Giancoli, Physics (6th ed): Instructor Resource Center CD-ROM, Prentice Hall, 2005 Viennot 2006 Denying the validity of a law at univesity (first year)

6. Archimedes’ upthrust : a classical solution M air-inside =  air-inside V M air-outside- sameV =  air-outside V W basket+… + gM air-inside = gM air-outside- sameV T in p in = p out = p 0 T out W  = M mol p 0 /RT Etc … … but Denying the validity of a law

7. … serious consequences! But, with uniform pressure… Mg pOpO pOpO pOpO pOpO Archimedes, where are you? Denying the validity of a law

8. How does it work? pOpO Pressure gradients… p int ↘ with the altitude p ext ↘ with the altitude … the very basis of fluid statics! Aperture Top  h p p in > p out Denying the validity of a law

9. Oversimplification: intrinsic risks Teachers’ and students’ critical faculty: an essential condition to good quality learning Perhaps the most difficult, and yet the most important kind of event to create in the classroom is critical dialogue, which recognises that inquiry proceeds by being critical of proposed ideas. It cannot help that essentially no examination questions ever require the student to offer a criticism, even the simplest. Such a focus on being critical is surely one of the greatest deficiencies that the movement for inquiry based learning needs urgently to face. Ogborn 2012

10. Moreover: a common view Students’ « competences », in particular critical faculty, is what matters It should be our primary goal Concepts will come after, as a secondary goal?

11. For instance European Commission Science education for responsible citizenship 2015 Success in the 21st century depends upon acquiring key competences rather than simply learning facts. Being able to collaborate, listen to the ideas of others, think critically, be creative and take initiative, solve problems and assess risk and take decisions and constructively manage emotions are interdependent. … to develop the competencies for problem- solving and innovation, as well as analytical and critical thinking that are necessary to empower citizens to lead personally fulfilling, socially responsible and professionally- engaged lives;

12. Can we help students develop their critical faculty without a conceptual basis? Alarming reports There is a real danger that Inquiry-based learning presents scientific knowledge as “knowledge in pieces”. Ogborn 2012 -These students...(France, end upper second. 2013) see physics as disordered and anarchical. Zabulon 2013 -See also Lie, S., Angell, C. & Rohatgi, A. 2012 Interpreting the Norwegian and Swedish trend data for physics n the TIMSS Advanced Study, Nordic Studies in Education, Vol. 32, pp. 177–195 Oslo

13. To which extent the way students’ critically analyse a very incomplete explanation is linked to, and/or develops along with their comprehension of the topic ? An investigation After a pilot study about the hot air balloon: Mathé & Viennot 2009

14. Analysing some internet texts about radiocarbon dating Questions that might be posed: N=N 0 exp (-t/  )  =5730 years No decay in the atmosphere? N 0 ??? What is well known:

15. Radio carbon dating : some crucial conceptual items … [ 14 C ] living organisms+ atmosphere uniform [ 14 C] living organisms+atmosphere constant in time ????? Radioactive decay 14 C  14 N + electron+ antineutrino Creation « Cosmic » neutrons + 14 N  14 C + proton Time rate decay 14 C = time rate creation 14 C « same t-rate » ????? Time rates V/s existing numbers, 14 C dN C /dt= - N C (1/  ) exp (-t/  ) Total number  [ 14 C] + [ 14 N]  N T constant in time Transitory phase adaptation through factor N C beyond N=N 0 exp (-t/  )  =5730 years

16. Adaptation through factor N : an analogy In a country Number of people living in towns U Number of people living in countryside C U+C= constant in time Move from town to countryside 10% per year Move from countryside to town 40% per year Steady state: 0,1 U ss = 0,4 C ss  U ss = 4C ss Transitory states: U > U ss  dU/dt exit > 0,4 U ss and dC/dt exit  0,1 C ss  U↓ and C  U  U ss  dU/dt exit  0,4 U ss and dC/dt exit > 0,1 C ss  U  and C↓

17. Radiocarbon dating, beyond N=N 0 exp (-t/  ) … ????? A series of texts (T1, …, T6) from popularisation literature + web, providing more and more elements of information to the reader. Our research design

18. T1T2T3T4T5T6 [ 14 C] decay after death, known law X 14 N  14 C high atm. X [ 14 C] uniform in living beings XX N=N 0 exp (-t/t )X N 0 (or [ 14 C]) constant in time (lb) X d[ 14 C]/dt time rate of creation : constant in time X decay % creation « same t-rate » X (replacement)X steady stateX transitory regimeXX 14 C  14 N X [ 14 C] + [ 14 N] = N T constant in time X Adaptation through factor N X

19. Prospective teachers, 4th year at university Goal: observing their successive reactions after reading each of these texts Ten interviews

20. PhaseWhat students are asked forsourceAspects of the discussion Step 1Did you hear about Radiocarbon dating … Read T1 … What do you think? Need more? T1 The interviewer is attentive to students arguments, « mca » reactions, questions. Low input from interviewer Step 2Read T2 … What do you think? Need more? T2 Idem  Step 3 Read T3 …Idem  T3 Idem  Step 4 Read T4 …Idem  T4 Idem  + (if not previously raised) a question : « same rate »: coincidence? Step 5 Read T5 …Idem  T5 Idem  Step 6 Read T6 …Idem  T6 The interviewer is attentive to students arguments, « mca » reactions, questions. Strong input from interviewer. Step 7Global evaluation of the designExpressing feelings 20 The interviews: overall structure

21. Coding the interviews (thematic analysis) Conceptual level Extended list of conceptual statements « cci »+ « emergent» ones, e.g. 14 C  12 C + … Coding: a pair conceptual statement implied, number of the step : (same t-rate, S2) Statement spontaneously expressed  Statement from a text, explicitly taken into account  Critical and meta cognitive-affective level (« mca ») Agreement in the end of a step  Half-hearted agreement in the end of a step ≈ Question posed about a detaildl Question posed about a « crucial » pointcq Satisfaction after additional information m+ It is what I needed. I had forgotten. It’s more precise. Frustration because of insufficient explanation m- I wanted an answer, it doesn’t tell us anything more. It doesn’t explain why … It leaves more questions unanswered than before.

22. Some results Presentation restricted to results about: Critical attitude and meta cognitive affective aspects : « mca » aspects

23. S1S1 S2S2 S3S3 S4S4 S5S5 S6S6 S7S7 Prel  m+- cq m- cq 3 m+- cq 1 m- cq 3 m+  4 Bela ≈ dl  dl cq m- cq 3 m- cq 2 m- cq 1 m+  3 Lamb ≈ dl≈ dl 3 m-m- m- cq m- cq 2 m+  3 Olli  m+  dl 2 m- cqm- cq 2 m+  3 Mack  m+ m- dl cqm- cq m+  3 Iago ≈ m- dl  cq ≈ m- m+  2 Boul ≈  m+ m- cq m+  2,5 Vivi  m- cq m+  ≈ m-m- cq 2  3 Tann ≈ dl  m+ dl  m+   m+  4 Thib  m- cq m+  ()()m+  4 notations  OK ≈ OK end of step dl ask « details »crucial question cq unanswered cq answered m+ happy with a new piece of information m- frustrationLikert scale 1>4

24. S1S1 S2S2 S3S3 S4S4 S5S5 S6S6 S7S7 Prel  cq cq 3 cq 1 cq 3  4 Bela ≈ dl  dl cq cq 3 cq 2 cq 1  3 Lamb ≈ dl≈ dl 3 cq cq 2  3 Olli  dl 2 cq cq 2  3 Mack  dl cq cq  3 Iago ≈ dl  cq ≈  2 Boul ≈  cq  2,5 Vivi  cq  ≈cq 2  3 Tann ≈ dl  dl   4 Thib  cq  ()() m+m+ 4 notations  OK ≈ OK end of step dl ask « details »crucial question cq unanswered cq answered m+ happy with a new piece of information m- frustrationLikert scale 1>4 Questions asked by students

25. S1S1 S2S2 S3S3 S4S4 S5S5 S6S6 S7S7 Prel  m+ m- m-m-m+ m-m-m- m+  4 Bela ≈  m- m-m-m-m- m+  3 Lamb ≈≈ m- m- m- m+  3 Olli  m+  m-m-m- m+  3 Mack  m+ m-m-m- m+  3 Iago ≈ m-  m+  2 Boul ≈  m+ m-m-m- m+  2,5 Vivi  m- m+  ≈ m-m-  3 Tann ≈  m+   m+  4 Thib  m- m+  ()()m+  4 notations  OK ≈ OK end of step dl ask « details »crucial question cq unanswered cq answered m+ happy with a new piece of information m- frustrationLikert scale 1>4 « mca » aspects

26. At first, agreement expressed (strong or half-hearted agreement, questions about « details », new pieces of information welcome, (« I had forgotten », « it’s what I was missing ») After the first crucial question, only crucial questions, no agreement, frustration expressed (I wanted an answer, it doesn’t tell us anything more. It doesn’t explain why … It leaves more questions unanswered than before.) In the end, strong satisfaction expressed, anecdotal questions explicitly left aside. Typical progression

27. A model: co-development of critical attitude and conceptual understanding Critical attitude Conceptual progress First crucial question Questions about « details » Only crucial questions Time Viennot 2014b Décamp & Viennot 2015

28. Our question was To which extent the way students’ critically analyse a very incomplete explanation is linked to, and/or develops along with their comprehension of the topic ? Research results suggest: These two processes are strongly interdependent

29. Considering as desirable a Co-development of conceptual understanding and critical stance « Concept-driven interactive pathways » Implications for teaching A learning environment constructed in this perspective: Stressing coherence and links Nature of Science Possible source of intellectual satisfaction

30. Concept driven interactive pathways (CDIP) Conceptual target Interactive (with teacher/other participants) Progressive, step by step Providing links Enabling activation of critique Aiming at intellectual satisfaction Viennot & de Hosson 2015 Some examples

31. 31 Concept-driven interactive pathways about Diffuse reflection and transmission of light through transparent media

32. 32 Viennot de Hosson 2012 Workshop WCPE 2012: Muse project Preliminary investigation Absorption by pigments: beyond a dichotomic approach Research investigation, 8 interviewees*, 3rd year University A workshop, WCPE meeting in Istanbul 2012, N=22, MUSE project

33. 33 A pigment absorbs Pigments -absorb a part of the light received -diffuse the rest Reminder absorbs White light

34. An experiment and a question 34 A dim ambiant light A laser beam (632 nm) is directed toward black or various coloured areas Will the impact on Black, Green, Blue, … be visible? If yes, which colour?

35. CDIP 1 35 All or nothing? More or less

36. Main results: recapitulation Strong destabilisisation The two groups of pigments are unanimously identified: « More or less » unanimously expressed All interviewees realise that strong sources may « invalidate » the « all or nothing » rules. Striking meta cognitive and critical comments But difficult access to the meaning of percentages CDIP 1 Consequently …

37. 37 Viennot de Hosson 2015 Workshops: Muse project 2013 Concept-driven interactive pathway about Transmission of light through transparent media V/s thickness Research investigation, 6 interviewees*, 4th year Univ. A workshop in EPEC/ICPE 2013 (Prague, N=16), ESERA 2013 (Nicosie, N=12) MUSE project *Teaching interviews, Komorek & Duit 04

38. PhasegoalMaterial setting Aspects of the discussion RemStudents are reminded of the classical rules +cones Question: which operation comes to your mind:+,-,*,/? A colour mixer The students appropriate the classical rules, answer question “which operation …?” Filt-expDraw the curves accounting for the transmission of light through two, then three layers Spectra observed Predictions with arguments Filt-obs Atm Performing the experiment: Do they change their curves? – See the situation as a filtering case. Transform the curve Students asked to reconsider the curves The interviewer provides help for calculation and explains how to use the sensitivity curves (cones).. OilObserve oil’s colours, then apply a multiplicative procedure to the curve idem GeneAsk for an appropriate functionHelp find exponential FeelGlobal evaluation of the designExpressing feelings 38 The interviews

39. Which operation do you associate to the action of filters: + - * / ? Explain your reasoning A question absorbs Unanimous response: subtraction A reminder Mi Er rather…absorbed, there is really something taken off. Int Taken off. That’s what makes you say « subtraction » Mi That’s it.

40. Transmission of light through transparent media V/s thickness CDIP 2 40 Conceptual target For each wavelength, each successive « layer » (of same given « small » thickness) multiplies the incident light by the same factor (<1): a percentage. This may change the shape of the transmission curve with thickness, therefore also the colour of the transmitted light. Introduction to exponential dependence

41. Question Draw the curves accounting for the transmission of light through two, then three layers, knowing the curve for one layer:

42. a One layer b Two layersc Three layers Basis for a correct answer: For each wavelength, each successive « layer » multiplies the incident light by the same percentage 0,95*0,95 0,95*0,95*0,95 0,3*0,3 0,3*0,3*0,3

43. Absorption curves: students’ drawings

44. PhasegoalMaterial setting Aspects of the discussion RemStudents are reminded of the classical rules +cones Question: which operation comes to your mind:+,-,*,/? A colour mixer The students appropriate the classical rules, answer question “which operation …?” Filt-expDraw the curves accounting for the transmission of light through two, then three layers Spectra observed Predictions with arguments Filt-obs Atm Performing the experiment: Do they change their curves? – See the situation as a filtering case. Transform the curve Students asked to reconsider the curves The interviewer provides help for calculation and explains how to use the sensitivity curves (cones).. OilObserve oil’s colours, then apply a multiplicative procedure to the curve idem GeneAsk for an appropriate functionHelp find exponential FeelGlobal evaluation of the designExpressing feelings 44 The interviews

45. The observed spectra And with magenta …

46. Int : What did you use when constructing your answer, a line of reasoning founded on which type of operation? Vi: Subtraction, mainly. To : We add subtractions. Ch : It’s still a subtraction, a wavelength is taken off. Int : Even getting the peak thinner is a subtraction ? To : Yes it’s, yes, still subtraction. Blue is taken off. Students’ reactions to the experiment: do they change their curves? From a focus on subtraction…

47. Mi : Given that it is proportional, … (adding filters) we will end by selecting the spectral band of greatest transmission factor.. Th : We’ve just seen that differences were majored when layers were added. Mi : Yes, finally, yes, (…) a filter let pass eighty per cent, hence two filters let pass eighty per cent of eighty per cent. Yes, that’s really clear. More, we can now understand the fact of increasing the number of layers. (Int: mathematical operation?) Multiplication. Reactions to the xperiment performed (continued) … to a comprehension of the role of multiplication … and some meta cognitive comments To : Even after having done this (a multiplication) right from the beginning, I wouldn’t have interpreted this as a multiplication.

48. PhasegoalMaterial setting Aspects of the discussion RemStudents are reminded of the classical rules +cones Question: which operation comes to your mind:+,-,*,/? A colour mixer The students appropriate the classical rules, answer question “which operation …?” Filt-expDraw the curves accounting for the transmission of light through two, then three layers Spectra observed Predictions with arguments Filt-obs Atm Performing the experiment: Do they change their curves? – See the situation as a filtering case. Transform the curve Students asked to reconsider the curves The interviewer provides help for calculation and explains how to use the sensitivity curves (cones).. OilObserve oil’s colours, then apply a multiplicative procedure to the curve idem GeneAsk for an appropriate functionHelp find exponential FeelGlobal evaluation of the designExpressing feelings 48 The interviews

49. One layer: at zenith Transmission of light through layers of air

50. The atmosphere as a filter? A non obvious view! Ya : I see what hasn’t been diffusively reflected. It’s a dispersive medium, it’s not a filter. Int : When you’re told that the sky is blue, the blue light is diffusively reflected, it makes you think of which mathematical operation, with respect to the incoming light? To : Subtraction. What is transmitted is the rest. Ya : Even before doing it (the operation), I knew it was multiplicative. By contrast, from this to see the atmosphere as a filter, this, before, I wouldn’t have done it. Ya : The atmosphere as a filter, I had no idea of seeing things like that. … and still some meta-cognitive comments

51. Given the transmission curve for one layer … Vollmer & Gedzelman 2006

56. Understanding why we see the sun red at sunset

57. Transmission of light through layers of pumpkin seeds oil

58. More and more pumpkin seeds oil

59. Transmission spectrum? Kreft, S. & Kreft, M. 2007. Physicochemical and physiological basis of dichromatic colour. Naturwissenschaften 94, 935-939. A bold simplification

65. Students’ reactions to this CDIP

66. Satisfaction /interest/newness To Exponential function as we just saw it, it’ natural, definitely. Th I will not put any mark, but it would be very good, and I am intellectually very satisfied, and I end this interview with something righter, it means that it’s been useful. Th I wouldn’t have spontaneously used the word multiplication, I was not reasoning like that before coming here. (…) 66 Expressing feelings 3rd year university

67. Meta cognitive comments Th Perhaps, I would use the operation with the right data, but if I was asked an explanation, I would never have used the word multiplication. Critical stance To … Given this, should we tell our students, should we use the law of additivity bla bla bla! Is it correct to use it? No, it’s true, additivity is OK, it’s for subtractivity, (that there is a problem). Vi Show subtraction, if I can say, of colours, and come back afterwards on something that comes down to percentages, it’s rather, err, I don’t know if you would’ve presented it like that. (…) For a student who is not used to it, it might be very disturbing. - I- I 67 Expressing feelings: 4th year university

68. Satisfaction /interest/newness - Tough ideas worked through in groups. Useful discussions -Step by step, new ideas -A simple topic with profound knowledge -Guided process in a sequence with a big framework on the ground -Made me think -Approach to exponential, very interesting with context -Good assignment that really makes you think -…. activities that extended my thinking - …elements of self doubting and surprise 68 Expressing feelings: workshop participants EPEC-ICPE and ESERA (2013) EPEC-ICPE N= 16 (out of 22 participants) Interesting: 16/16 (max rating: 3) useful 12/16 (max rating: 3) ; 4/16 (rating: 2) ESERA N= 16 (out of 16 participants) Interesting: 16/16 (max rating: 3) useful 11/16 (max rating: 3) ; 4/16 (rating: 2); 1 (rating: 1)

69. Meta cognitive comments -It made me think about things I knew about perhaps intuitively, but I still think it was as if I did not know about them previously. Critical stance - The use of different thickness, we usually do with only one and I had the idea of subtraction 69 Expressing feelings: workshop participants EPEC-ICPE, ESERA (2013)

70. The reasons of a CDIP Searching for fundamental ideas (« x » instead of « -», ultimately, « x » means probabilist) While trying to keep formalism reduced Searching/taking into account students’ ideas (subtraction) Taking into account teaching rituals (« subtractive » synthesis, absorption « all or nothing, » ) Stressing links (atmosphere as a filter) Keeping simplification under control (non-toxical modelling) “Conciliation of a rather classical teaching scenario – one that is interactive, progressive, respecting a constraint of formal simplicity – with profound and fruitful ideas.” A new spotlighting for “well known” ideas

71. The content for teaching: a proactive-responsive route for designing a new spotlighting subject matter analysis Search for conceptual coherence, design of a new spotlighting, centrally important concepts, links respecting formal accessibility Student’s ideas, … Teaching rituals CDIP 1-2 Proactive decision 71 Echo-explanation

72. – Extreme conceptual reduction: There is a price to pay, need to be very careful, avoid ruining consistency, keep simplification under control, mind rituals – Students’ reactions: They appreciate consistency, need to reach a threshold of comprehension before daring to express their frustration in this respect, need: co-development of critical thinking and conceptual comprehension subtractive synthesis: all or nothing? – Showing that science aims at a unified « description » of the world: value of stressing conceptual coherence and links. -The merits of stressing « new » spotlightings of the content: « New » does not mean reinventing physics. Means attention to aspects of physics commonly disregarded, or kept implicit. Multiplicative instead of subtractive Concluding remarks

73. – Nourish a more balanced discussion about the objectives (content/ competences) and modalities of physics teaching (avoid manicheism). – In particular, see « active learning » as compatible with several types of learning activities, including critical dialogue. You made me think – Need to propose various approaches and means to be used in class practice, thus enlarging the range of teachers’ choices. Ex: CDIPs on the MUSE website MUSE More Understanding with Simple Experiments www.EPS.org Education, MUSE Concluding remarks …

74. Perspectives for research – More fine-grained investigations on what triggers a critical stance and a renewed exigency in students. – Investigate meta cognitive-affective components of students’ intellectual paths: *Awareness of the distance between doing and understanding: « Perhaps, I would use the operation with the right data, but if I was asked an explanation, I would never have used the word multiplication. … » * Intellectual satisfaction as an outcome of teaching/learning process

75. Thank you for your attention

77. Décamp, N. & Viennot, L. 2015. Co-development of conceptual understanding and critical attitude: analysing texts on radiocarbon dating, International Journal of Science Education, http://dx.doi.org/10.1080/09500693.2015.1061720http://dx.doi.org/10.1080/09500693.2015.1061720 Ennis, R. H. 1992. The degree to which critical thinking is subject specific: Clarification and needed research. The generalizability of critical thinking, 1992, p. 21-37. Komorek M, Duit R. 2004 The teaching experiment as a powerful method to develop and evaluate teaching and learning sequences in the domain of non‐linear systems. IJSE, 26(5):619–633. W. F. Libby, "Nobel Lecture: Radiocarbon Dating", In Nobel Lectures, Chemistry 1942-1962 (1964), Elsevier Publishing Company, Amsterdam. S. Lie, C. Angell & A. Rohatgi, Interpreting the Norwegian and Swedish trend data for physics in the TIMSS Advanced Study, Nordic Studies in Education, Vol. 32 (2012), 177–195. Mathé, S., & Viennot, L. 2009. Stressing the coherence of physics: Students journalists' and science mediators' reactions, Problems of education in the 21st century. 11 (11), 104-128. More Understanding with Simple Experiments: http://www.eps.org/ education, MUSEhttp://www.eps.org McPeck, J. 1992 Thoughts on subject specificity In S. Norris (Ed.) The generalizability of critical thinking: Multiple perspectives on an educational ideal (pp. 198–205) New York: Teachers College Press. Viennot L. 2006.Teaching rituals and students' intellectual satisfaction, Phys. Educ. 41, 400-408. http://stacks.iop.org/0031- 9120/41/400http://stacks.iop.org/0031- 9120/41/400 Viennot, L. 2014. Thinking in Physics, The pleasure of reasoning and understanding in physics. Springer/Grenoble Science Viennot, L. 2014 Codevelopment of conceptual understanding and critical attitude: an essential condition for physics learning. Invited address. Frontiers of fundamental physics FFP14, Marseille July 2014. PoS(FFP14)011 Viennot, L. & de Hosson 2012 Beyond a dichotomic approach, the case of colour phenomena. International Journal of Science Education, 34:9, 1315-1336. Viennot, L. & De Hosson, C. 2015. From a Subtractive to Multiplicative Approach, A Concept-driven Interactive Pathway on the Selective Absorption of Light, International Journal of Science Education, 37:1, 1-30. DOI: 10.1080/09500693.2014.950186 Willingham, D.T. 2007. Critical thinking, Why is it so hard to teach ? American Educator, 8-19. T. Zabulon, On the linking between secondary teaching and higher education in physics and chemistry, 61e National Conference of Union of Physics and Chemistry Teachers (UdPPC) Reports on round tables, BUP (2013), 2011-2016.