Supporting Students in Building Interdisciplinary Connections. Chandra Turpen

Transcription

1 Supporting Students in Building Interdisciplinary Connections Chandra Turpen

2 OUR RESEARCH TEAM Chandra Turpen Julia Svoboda Gouvea Vashti Sawtelle Benjamin Dreyfus* Benjamin Geller* Kim Moore* Wolfgang Losert E. F. (Joe) Redish Arnaldo Vaz 2

3 Setting the Stage We have been iteratively re-designing the introductory physics sequence required for all life science majors. Two instructors run 2 small pilot sections of students Six instructors run 6 different sections of ~120 students each One instructor for a small pilot section of 20 students Significant shifts in topics & Significant shifts in pedagogy

4 Shifting Topics - Energy & Entropy Chemical Bond Energy Chemical Energy (ATP) Entropy as the distribution of energy Potential & Kinetic Energy Random Motion & Diffusion Entropy ΔG = ΔH - TΔS (oil & water) 4

5 5 Talk Outline

6 6 Talk Outline

7 Compelling Dilemma Breaking a bond requires an input of energy Breaking the phosphate bond in ATP yields energy

8 ATP: the energy currency of the cell Adenosine triphosphate is produced during cellular respiration and photosynthesis. In ATP hydrolysis, the phosphate bond is broken, stronger bonds are formed, and the net effect is that energy is released. 8

9 Compelling Dilemmas Breaking a bond requires an input of energy Energy is conserved Particles don t know where high concentration is Things tend toward disorder Like repels like (electrostatic interactions) Breaking the phosphate bond in ATP yields energy We worry about conserving energy in everyday life Particles move from high to low concentration Organisms exist (in a stable form) Like attracts like (polar/non-polar intermolecular interactions) 9

10 Why organize curricula around compelling dilemmas? These dilemmas: are grounded in student prior knowledge are related to big ideas that span physics & biology are compelling to students motivate students to refine models and generate satisfying explanations Addressing these dilemmas falls outside of what is canonically covered in physics & biology. 10

11 Addressing dilemmas results in valuable student outcomes Students can make significant progress in addressing these dilemmas While doing so students o build substantive cross-disciplinary bridges o deepen their disciplinary understandings o develop competence in modeling in science We can shift our focus in intro physics & still succeed in teaching central physics ideas. However, instructional support is required. 11

12 12 Talk Outline

13 Attending to Students Ideas What do you know about energy? 13

14 Instructional Support Guidance from the instructor: o o o what do you already know? what do you mean by those terms? does that sound plausible? (inviting students to evaluation the contribution) Students initial ideas point to opportunities for reconciliation Our course provides multiple opportunities to grapple with, pursue, and coordinate these ideas. 14

15 Quiz question (from Galley 2004) An O-P bond in ATP is referred to as a high-energy phosphate bond because A. The bond is a particularly stable bond. B. The bond is a relatively weak bond. C. Breaking the bond releases a significant quantity of energy. D. A relatively small quantity of energy is required to break the bond. 79% 15

16 Discussing the ATP Quiz Question The results were that 79% of you picked C. If you want to make an argument why you think that should be accepted as an answer, write on the back, say I gave C, and I think you want to accept this as an answer because of the following. If you have a good thoughtful answer I don t know how they use the language in chemistry and biology, and if they talk about it as C, you might have a case. If you feel you can make it, do so. I m perfectly willing to listen. 16

17 Negotiating disciplines in-class Gregor: So I, and I guess probably a lot of other people, were assuming something that was not part of the question, that was that a more stable bond would be formed by breaking that bond, which would Instructor: Write it up! Write it up. That's your justification. Gregor: But that's the assumption that we were making Instructor: Yes. And because you had some context that you were assuming that wasn't specified, or because this always happens in some context when you use it in biology that I wouldn't know about it, let me know. 17

18 Interdisciplinary reconciliation vs ATP Breaking bonds requires energy ATP hydrolysis produces energy Gregor ATP hydrolysis involves breaking off a phosphate (energy input) and forming new bonds with water (energy output) 18

19 Students achieve reconciliation ATP -> ADP + P i 19

20 What did Gregor mean? I put that when the bond's broken that's energy releasing. Even though I know, if I really think about it, that obviously that's not an energy-releasing mechanism. Because like, you can't break a bond and release energy, like you always need to put energy in, even if it's like a really small amount of energy to break a bond. 20

21 Reconciling When I was taking the test, I guess I was thinking breaking this bond then leads to these other reactions inevitably. That result in an energy release. I don't [argue] that breaking a bond releases energy, but just like in a larger biological context, that reaction does release energy. 21

22 Tagging the disciplines I guess that's the difference between like how a biologist is trained to think, in like a larger context, and how physicists just focus on sort of one little thing. 22

23 How to bound the system ATP hydrolysis: Breaking the phosphate bond in ATP Formation of new bonds Physics? Breaking a bond requires an input of energy Biology? Breaking the phosphate bond in ATP yields energy 23

24 24 Talk Outline

25 Positive Student Outcomes Skilled at reasoning within each discipline, using its own tools Built interdisciplinary coherence: know how these tools relate & how they are coherent with one another Skilled at articulating modeling choices about how to bound the system This context-dependent reasoning may be productive! 25

26 NEXUS/Physics: A context where Percentage biology majors are successful Pre/Post FMCE Total (37) Force & Motion Conceptual Evaluation: Pre/post assessment Conceptual understanding of force, motion, & energy Total (33) Energy Pre-% Post-% Typical Normalized Gains: Lecture: 10%-30% Interactive: 30%-40% Highly interactive: 40%-80% NEXUS/Physics Gain ~35% Energy Cluster ~.40 26

27 Compelling Dilemmas Breaking a bond requires an input of energy Energy is conserved Particles don t know where high concentration is Things tend toward disorder Like repels like (electrostatic interactions) Breaking the phosphate bond in ATP yields energy We worry about conserving energy in everyday life Particles move from high to low concentration Organisms exist (in a stable form) Like attracts like (polar/non-polar intermolecular interactions) 27

28 NEXUS/Physics: A context where biology majors are successful Utility of Simple Models PRE POST SHIFT 0.0% 20.0% 40.0% 60.0% 80.0% Students make impressive strides into seeing the utility of simple models in physics and biology. 29

29 Students seek connections Catabolic (breaking bonds) Anabolic (making bonds) Release energy? Betsy 31

30 Students seek connections Anabolic & Catabolic Pathways 32

31 Students seek connections So like in bio they kind of just like glaze over this and they just say "Oh, know that these cause these to go" but when I like think of, like the-- more in detail about it, it doesn't make sense to me. Betsy 33

32 Student can: build substantive cross-disciplinary bridges deepen their disciplinary understandings develop competence in modeling in science seek interdisciplinary coherence (beyond our curriculum) 34

33 NEXUS/Physics: A New Physics for Biologists Class Chemical Bond Energy Bound States ATP Essay Question Dreyfus, B.W.., et al. (in press) American Journal of Physics Entropy Random Motion & Diffusion Entropy as the distribution of energy ΔG = ΔH - TΔS (oil & water) Geller, B.D., et al. (in press) American Journal of Physics Redish, E.F., et al. (in press) American Journal of Physics 35

34 END THANK YOU! 36