Examining the Connection Between Physics and Biology...

Examining the Connection Between Physics and Biology Instruction

Through Three Lenses: Content, Cognition, and Culture

Edward (Joe) Redish University of Maryland 6/8/14

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Building a physics course for biology majors: Some questions

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  How can a physics course “fit in”? Can it articulate effectively with the biology, chemistry, and math classes that bio students take?   What expectations do bio students have about physics – and science in general – that play a role in how they interpret learning in physics?   How do disciplinary differences effect what and how we ought to teach?

Outline


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  Context: NEXUS/Physics:   Content: Fitting into the Curriculum   Cognition: The Resources Framework

 Concepts: KiP  Epistemology

  Culture: The communication divide   Implication for Instruction: Teaching physics standing on your head

NEXUS/Physics

Context

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In the summer of 2010, HHMI offered four universities the opportunity to:

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Develop prototype materials for biologists and pre-meds in

  Chemistry (Purdue)   Math (UMBC)   Physics (UMCP)   Capstone case study course (U of Miami)

that would  take an interdisciplinary perspective  be competency based


Changing the goals of the course


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  Explicitly serve biology students and faculty by articulating with the biology curriculum

 Provide support for biology majors for difficult physics concepts that they will encounter in biology and chemistry classes, particularly those that cannot be studied in depth in those classes.

  Do this by using methods common in intro physics  Use simplified models to build understanding,  Build a sense of physical mechanism,  Develop coherences between things that might seem contradictory, etc.

Changing the culture of the course

  Seek content and examples that have authentic value for the biology curriculum.

 Students should see the course as helping them understand things are important for learning biology.  Faculty teaching upper division biology (and chemistry) should want physics as a pre-requisite.  Finding specific examples where physics applies to biology is not enough.

  Assume this is a 2nd year college course.  Biology, chemistry, and calculus are pre-requisites.

  Use interactive engagement pedagogy. 6/8/14 Gordon Conference

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Redish et al., Am. J. Phys 82:5 (2014) 368-377

The NEXUS/Physics timeline: Iterative research based design

  2010-11   Extensive discussion and negotiation among stakeholders.

  2011-12   Create on-line reading materials, problems   Teach a small test class (N ~ 20)

  2012-13   Refine and expand materials   Team teach two small flipped classes (N ~ 20)   Create new laboratories

  2013-14   Becomes the required course for all bio majors.   Fall: Deliver in two large lectures (N ~ 120): instructors from the design team.

  Spring: Teach both section in 4 large lectures with 4 new instructions.


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Detailed research on student responses – observation, interviews, surveys

Fitting with the biology curriculum

Content

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Interdisciplinarity: Rethinking the content

  Choose content that articulates with required introductory biology and chemistry classes.   Cover physics content that helps students develop insight into fundamental ideas of importance in biology.   Suppress traditional content of peripheral value.   But ... This is a course in which students are expected to learn the physics – and see how it can be of value to biology. It is NOT a course in “physics add-ons for biologists.”


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So ... maintain the crucial components of “thinking like a physicist”

  Reasoning from broadly valid principles   Quantification,   Mathematical modeling,   Mechanism,   Multiple representations   Coherence   Value of abstract thinking   Value of global principles (true, “whatever” is happening “inside”)


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New topics


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  Focus on modeling and explicating assumptions.   Do micro and macro examples throughout assuming students know about atoms.   Include discussion of chemical energy and reactions   Treat random motion as well as coherent. (Labs!)   Carefully build the basic statistical mechanics support for thermodynamics (conceptually).   Expand treatment of fluids and physics in fluids.

Dreyfus et al., Am. J. Phys 82:5 (2014) 403-411 Geller et al., Am. J. Phys 82:5 (2014) 394-402 Moore et al., Am. J. Phys 82:5 (2014) 387-393

The Resources Framework

Cognition

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Key cognitive foothold ideas

1.  People have a huge store of long-term memories

2.  Items in memory are associated and can activate or inhibit each other.

3. Memory is reconstructive and dynamic. 4. Working memory is limited. 5.  Access to long-term memory is controlled

by executive function.


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Redish & Smith, J. of Eng. Educ 97 (2008) 295-307

The Resources Framework: A multi-level structure


  Concept knowledge (basic knowledge)  Compilation and chunking  Knowledge organization (associations)

  Knowledge about when to use knowledge (switching mechanisms or control structures)

  Cultural knowledge   Framing   Epistemology

  Affect (emotional response)  Feelings (fear, self confidence, aesthetics)  Motivation  Identity

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Level 1: Knowledge in Pieces: Concepts based on embodied experience


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  Phenomenological primitives (observed)   Reasoning primitives (descriptive/inferred)   Associational patterns

Redish, Fermi Summer School CLVI (2003) Sabella & Redish, Am. J. Phys. 75 (2007) 1017-1029


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Example: Why do we have seasons?

  Essentially every elementary school student in the USA has been given the explanation.

  Then why do Harvard graduates give the wrong answer when asked?

R-Prim: Closer is stronger / more effective (neither right nor wrong) P-prim: You can get warmer by standing closer to the fire.(right) Associational p-prim: It’s warmer in the summer, so we must be closer to the source of the heat.(wrong)

A Private Universe, http://www.learner.org/resources/series28.html

Misconceptions


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  A misconception is a student error that is commonly and reliably activated in a given context by many students.

  A misconception may be something that  Has been learned and remembered incorrectly (or taught incorrectly).   Is generated quickly and naturally by students on the spot as a result or commonly held resources and associations. (common)   Is part of a coherent alternative framework that is non-productive for scientific thinking. (rare)

  The appropriate instructional responses to these structures are dramatically different.

Misconceptions


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  A misconception is a student error that is commonly and reliably activated in a given context by many students.

  A misconception may be something that  Has been learned and remembered incorrectly (or taught incorrectly).   Is generated quickly and naturally by students on the spot as a result or commonly held resources and associations. (common)   Is part of a coherent alternative framework that is non-productive for scientific thinking. (rare)

  The appropriate instructional responses to these structures are dramatically different.

Having a fine-grained view of misconceptions suggests paths to more effective instructional environments.


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  It allows us to “refine & reconcile” students’ thinking rather than “confront & replace.”   It makes it possible to avoid the negative epistemological side effect of students deciding that their intuition is untrustworthy.

Elby, Am. J. Phys. PER Supplement 69:S1 (2001) S54-S64

Level 2: Switching mechanisms: Framing and epistemology


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  The limitations of working memory make social knowledge and perception of the learning environment critical. Of all the knowledge we have, what should we use in a given situation?   Framing

 The process by which one answers the question: “What’s going on here?” (calling on social knowledge, experience, and expectations)

  Epistemology  The study of answering the questions: “What is the nature of the knowledge we are learning?” and “What are we supposed to do in order to learn it?” (how we decide we know something)

Framing

  The behavior of individuals in a context is affected by their perception and interpretation of the social context in which they find themselves.   That perception and interpretation acts as a control structure that governs which of their wide range of behavioral responses they will activate / use in a given situation.   Framing is the process in an individual that interfaces the cognitive and the socio-cultural.

6/8/14 Gordon Conference Hammer, Elby, Scherr, & Redish, in Transfer of Learning: Research and Perspectives, J. Mestre, ed. (Inf. Age. Pub, 2004) .

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Structures and concepts useful for analyzing epistemological issues


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  Warrants   Specific statements explaining why a particular claim is true using specific reasoning.

  Epistemological resources (e-resources)   Generalized categories of “How do we know?” warrants.

  Epistemological framing   The process of deciding what e-resources are relevant to the current task. (NOT necessarily a conscious process.)

  Epistemological stances   A coherent set of e-resources commonly activated together in a particular circumstance

  Epistemic games   A structured activity usable for approaching a variety of knowledge building tasks and problems.

Bing & Redish, Phys. Rev. ST-PER 5 (2009) 020108; Phys. Rev. ST-PER 8 (2012) 010105. Tuminaro & Redish, Phys. Rev. ST-PER 3 (2007) 020101.

Epistemic games


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  An epistemic game is “a coherent activity that uses particular kinds of knowledge and processes associated with that knowledge to create knowledge or solve a problem.”*

* Collins & Ferguson, Educ. Psych. 28 (1993) 25 Tuminaro & Redish, Phys. Rev. ST-PER 3 (2007) 020101

Note: This example is a lot more algorithmic than most epistemic games. They tend to provide structures and tools but not step-by-step methods. The canonical non-physics example is “making a list.”


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 Can a fine-grained analysis of disciplinary-specific epistemological resources, framing, and stances help us create better instructional environments and practices in physics for biology students?

The Communication Divide

Culture

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Social knowledge and disciplinary expectations


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  Students choose a field because, in part, they have some expectations about what it does and how it functions.   In learning to become disciplinary experts, students are acculturated to the methods and ways of thinking practiced in the discipline.   These two sets of expectations do not necessarily match, nor do they necessarily match with those of their (outside of discipline) instructors in service courses.

Epistemological resources


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Knowledgeconstructed

from experience and perception (p-prims)

is trustworthy

Algorithmic computational steps lead to a trustable

result

Information from an authoritative

source can be trusted

A mathematical symbolic representation faithfully

characterizes some feature of the physical or geometric

system it is intended to represent.

Mathematics and mathematical manipulations

have a regularityand reliability and are

consistent across different situations.

Highly simplified examples can yield

insight into complex mathematical

representations

Physical intuition (experience & perception)

Calculationcan be trusted

By trusted authority

Physical mapping to math

(Thinking with math)

Mathematical consistency

(If the math is the same, the analogy is good.)

Value of toy models

IntroPhysicscontext

(Small bubbles are shorthand for the big ones.)

Epistemology is dynamic and responds to a variety of expectations.


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Analyzing the framing shift of an engineering student to a physics problem he had not seen before.

Gupta & Elby , Int. J. Sci. Ed 33:18 (2011) 2463-2488

•  Coordinated math and intuition

•  Positive affect

IntroBiologycontext

Epistemological resources


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Knowledgeconstructed

from experience and perception (p-prims)

is trustworthy


Information from an authoritative

source can be trusted


The historical fact of natural selection leads

to strong structure-function relationships

in living organisms

Many distinct components of

organisms need to be identified

Comparison of related organisms yields

insight

Learning a large vocabulary

is useful

Categorization and classification

(phylogeny)

Teleology justifies

mechanism

There are broad principles that govern

multiple situations

Heuristics

Living organisms are complex and require multiple

related processes to maintain life

Life is complex(system thinking)

(Small bubbles are shorthand for the big ones.)

Note:


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  These groupings of resources are labeled as “Intro Bio” and “Intro Physics.”   This is to indicate that these are epistemological resources commonly perceived by students as relevant in their intro classes in these subjects.   Professionals in both fields tend to use both of these sets resources (though with different distributions and depending on sub-field).

Ashley’s response to the use of math in Org Bio


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I don’t like to think of biology in terms of numbers and variables…. biology is supposed to be tangible, perceivable, and to put it in terms of letters and variables is just very unappealing to me…. Come time for the exam, obviously I’m going to look at those equations and figure them out and memorize them, but I just really don’t like them. I think of it as it would happen in real life. Like if you had a thick membrane and tried to put something through it, the thicker it is, obviously the slower it’s going to go through. But if you want me to think of it as “this is x and that’s D and this is t”, I can’t do it.

Discussing the use of Fick’s Law in controlling diffusion through a membrane of different thicknesses.

Another response of a student to math in Org Bio


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The little one and the big one, I never actually fully understood why that was. I mean, I remember watching a Bill Nye episode about that, like they built a big model of an ant and it couldn’t even stand. But, I mean, visually I knew that it doesn’t work when you make little things big, but I never had anyone explain to me that there’s a mathematical relationship between that, and that was really helpful to just my general understanding of the world. It was, like, mind-boggling.

The small wooden horse supported on dowels stands with no trouble. When all dimensions are doubled, however, the larger dowels break, unable to support the weight.

Watkins & Elby, CBE-LSE 12 (2013) 274-286.

Ashley’s dynamic switch


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“Biological authenticity” – •  Coordinated math and intuition •  In a biological context •  Positive affect •  Significant value for

understanding biology

Recitation task: Why do bilayers form?


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Prompt: Which term wins?

Prompt: …explain how phospholipids can spontaneously self-assemble into a lipid bilayer…why this particular shape?


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Hollis: I mean, in terms of like bio and biochem, the reason why it forms a bilayer is because polar molecules need to get from the outside to the inside ... so you need a polar environment inside the cell. But I don't know how that makes sense in terms of physics. So... Cindy: So like what I'm saying is, you have to have, like if it's hydrophobic and interacting with water, then it's going to create a positive Gibb's free energy, so it won't be spontaneous. So, in this case, you have the hydrophobic tails interacting with whatever's on the inside of the cell, which is mostly water, right? Hollis: Or other polar molecules. Cindy: Yeah, other polar molecules. It's going to have, and that's bad ... That's a positive Gibb's free energy. Hollis: Yes. See, you explained it perfectly ... Cause I was thinking that, but I wasn't thinking it in terms of physics. And you said it in terms of physics, so, it matched with bio.

Disciplinary epistemologies


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  “in terms of bio, the reason why it forms a bilayer is because polar molecules need to get from the outside to the inside   “ if it’s hydrophobic and interacting with water, then it's going to create a positive Gibb's free energy, so it won't be spontaneous and that’s bad..”


41 IntroPhysicscontext

IntroBiologycontext



Teleology justifies

mechanismSatisfaction(smile,

fist pump)

Interdisciplinary coherence

seeking

“Interdisciplinary coherence” – •  Coordinated resources from

intro physics and biology •  Blended context •  Positive affect

Teaching Physics standing on your head

Implications for Instruction

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Does this help?


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  An epistemological analysis provides a finer-grained approach to understanding student response to instruction.   That might help us both understand the problems in student-faculty communication and in helping us design effective instructional environments.

 Example 1: The “go-to” e-resource  Example 2: A potentially useful e-game

Example 1: The “go-to” e-resource


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 The epistemological stances naturally taken by physics instructors and biology students may be dramatically different – even in the context of a physics class.  One example from my observations of other faculty teaching NEXUS/Physics yields an insight.

The figure shows the PE of two interacting atoms as a function of their relative separation Is the force between the atoms at the separations marked A,B, and C attractive or repulsive?

C

B A Total energy

r

Potential Energy


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How two different professors explained when students got stuck on this.


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  Remember! (or here)   At C, the slope of the U graph is positive.   Therefore the force is negative – to smaller r.   So the potential represents an attractive force when the atoms are at separation C.

F = −∇U F = − dU

dr

This figure was not actually drawn on the board by either instructor.

Wandering around the class while the students were considering the problem, I found a good response with a different approach.


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  Think about it as if it were a ball on a hill. Which way would it roll? Why?   What’s the slope at that point?   What’s the force?   How does this relate to the equation

F = − dU

dr

I conjecture that a conflict between the epistemological stances of instructor and student make things more difficult.


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Calculationcan be trusted







Mathematical consistency

(If the math is the same, the analogy is good.)

Physics instructors seem more comfortable beginning with familiar equations – which we use not only to calculate with, but to code and remind us of conceptual knowledge.

Most biology students lack the experience blending math and conceptual knowledge, so they are more comfortable beginning with physical intuitions.

Teaching physics standing on your head


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  For physicists, math is the “go to” epistemological resource – the one activated first and the one brought in to support intuitions and results developed in other ways.   For biology students, the math is decidedly secondary. Teleology (structure/function) tends to be the “go to” resource.   Part of our goal in teaching physics to second year biologists is to improve their understanding of the potential value of mathematical modeling. This means teaching it rather than assuming it.

Example 2: A game they missed


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When a small organism is moving through a fluid, it experiences both viscous and inertial drag. The viscous drag is proportional to the speed and the inertial drag to the square of the speed. For small spherical objects, the magnitudes of these two forces are given by the following equations:

Fv = 6πμRv

Fi = CρR2v2

For a given organism (of radius R) is there ever a speed for which these two forces have the same magnitude?

Students were seriously confused and didn’t know what to do next.


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  “Should I see if I can find all the numbers on the web?”   “I don’t know how to start.”

 “Well, it says ‘Do they ever have the same magnitude?’ How do you think you ought to start?

  “Set them equal?”   “I don’t know what all these symbols mean.”

 “Well everything except the velocity are constants for a particular object in a particular situation.”

  “Oh! So if I write it .... Av = Bv2... Wow! Then it’s easy!”

A useful epistemic game


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Conclusion


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  In trying to create a new, more effective physics course for biology students, our qualitative research gave us many surprising insights into what worked for this population of students and what didn’t.   An cognitive modeling of student responses focusing on epistemological resources gives a fine-grained understanding of disciplinary differences that may lead to a better understanding of how to create effective instructional environments.

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