PART I: BACKGROUND

Title: “Helping students understand ‘connections’ between physics and biology” Authors: Shusaku Horibe, Department of Curriculum and Instruction; Bret Underwood and Peter Timbie, Department of Physics, University of Wisconsin-Madison Contact: horibe@physics.wisc.edu; bjunderwood@wisc.edu Discipline or Field: Physics, Biology Date: Course Name: First semester calculus-based introductory physics intended for life science majors (Physics 207)

Course Description: This calculus-based introductory physics course is recommended for those students majoring in science or mathematics, but is also suitable for those with prior experience with calculus.  The course satisfies a physical sciences requirement for the biological sciences major.  The course covers the topics of mechanics, heat, and sound.  The class meets twice a week for a 50 minute lecture given by a faculty member, twice a week for a 50 minute discussion and one three hour lab per week, the latter two led by a Teaching Assistant.  Approximately 250 students enroll in this course every semester, of which approximately 50% are biological science majors, 32% are physical science majors (such as physics or chemistry), and 13% are engineering majors.  The lesson was performed over half-way through the semester, during a unit on fluids, and only took place within the 3 hour lab of one week, in which the students have been working in the same groups throughout the semester.       Executive Summary:

The goal of the lesson is for students to develop an understanding of how physics is connected to biology through the building of physics models of biological phenomena.

We developed three versions of the lesson, evaluating Versions 1 and 2 and making changes based on those evaluations. In Version 1 students engaged in model building activities and were asked to develop physics-based models for a variety of biological and physiological facts. In Version 2 significant modifications were made to address difficulties students had in meeting the learning goals of Version 1. In particular, the number of different biological facts students were asked to model was reduced significantly, and more attention was paid to developing students’ model building skills. Only minor modifications were made in Version 3 to help provide more feedback and a clearer framework for model building to students.

We found that students suffered from several difficulties that prevented them from achieving the learning goals: a lack of conceptual understanding; underdeveloped models; and a lack of reflection on the models that they built. The revisions in the lesson were designed to address these difficulties, resulting in a lesson, which provides ample opportunities for feedback to students on the model building process and how it helps to make connections between physics and biology.

PART II: THE LESSON   In our lesson study project, we have gone through 2 complete lesson-study cycles and ended up with three versions of the lesson, each being revised based on collected findings of student learning. We did not use the version 3 to study the lesson, but it would be interesting to see how some of the changed made to version 2 helped students achieve the learning goals of the lesson.

Version 1  Learning Goals: Students’ primary (immediate) learning goal is: To understand how the principle of pressure is relevant to understanding various physiological facts about different organisms, particularly blood circulation in the absence and presence of gravity. In particular, after the completion of this lab, students should be able to: 

1. Provide real examples of the relevance  2. Provide quantitative analysis of the examples  3. Discuss limitations of the models that they develop

  The long-term (developmental) learning goal of this lab is: To learn some aspects of thinking like a physicist. In particular, students should be able to:

1. To recognize and demonstrate how physics principles apply to real life2. To build simple models of some natural facts using physics principles3. To evaluate advantages and disadvantages of different physics models 4. To appreciate the usefulness of physics in understanding nature

Lesson Design:

Previous Activities: The lesson fits in a standard first-semester calculus-based physics. They have just finished or concurrently learning about the basic fluid mechanics and dynamics, which typically comes after the entire mechanics section.

Lesson Overview: The lesson is for a 3-hour-long lab in an introductory physics course. First, students are introduced to the idea of model and model building in physics by the instructor. Then, the lesson involves a series of group activities, in which students are presented with interesting physiological facts and asked to build models using physics concepts and principles that would explain those facts.

Lesson Sequence:

Introduction Some kind of introduction to what is going on with the lesson study…? Maybe we should tell them to

ignore the people in the back observing, treat them as if they are there. Introduction about the instructor Tell students explicitly about the learning goals of the lesson as well as the end-of-the-lesson task

they will be asked to do

Discussion of Model Building Begin with a general discussion of what a model is.

o Model is a simplified representation that encapsulates and helps us understand the essence of phenomena. Because it is simplified, the model is limited but allows us to make predictions.

o We can do this through the example we used in the pre-lab or use new examples. But the discussion of models should be done through concrete examples that students are familiar with.

o We will not assume that students have read the lab manual and understood it thoroughly. So, the discussion will be a reiteration of what is in the pre-lab sheets.

Based on the pre-lab work in which students were asked to come up with a few examples of models of nature, launch a discussion about what we mean by ‘model building’.

o Students can first share their work within the group and discuss how good or bad their models are or how they could be modified.

o They can share this with the entire class what they have.  

From here on, students will engage in a series of model-building activities. Various physiological facts and some non-physiological facts of different organisms will be presented to the students. They will be asked to build models that are based on physics principles to explain these facts. In the beginning, they will be guided on how to actually make models and apply them. Towards the end, they will have to come up with their own model and explanations largely on their own.  

Giraffe’s Skin Students are given the observation that “The skins of giraffes are tighter in their legs than the upper

part of their body.”    First, we will instruct them to come up with as many hypothetical models as possible. They can be

nothing more than “guesses.” At this stage, brainstorming for ideas may be the best. They will be doing this in the group. 

We do not want to exclude non-physics hypothesis; on the contrary, we would welcome such hypotheses. We want to encourage that there really isn't one right answer at this stage for the value of the answer will be determined by the extent to which it is simple, it explains the phenomena, it is qualitatively accurate, it is connected to other phenomena, it predicts some novel phenomena and perhaps on aesthetics of it. 

After groups discuss among themselves, they will share their finding with the rest of the class.  At this point, students have many hypotheses but have not figured out which one is better than the

other.  We could pose the question here what physics principles may be relevant here? Kinematics, Force,

Energy, Pressure… etc.?  Students have gathered ideas but have not generated any substantive models. After we have identified

a possibly relevant physics principle, we will review it, not through formulas alone, but through a physical embodiment of the principle. Even if we identify the relevant principle, it is difficult to just make the simplification of the natural phenomena. We do not think making the simplification is a trivial task. The result we want to do is to have them say, “Can we treat the giraffe’s blood vessels as a uniform tube of blood?” But, of course, to reach this simplification, it requires the insight that the relevant principle here is pressure. We should try to elicit this insight as much as possible from the discussion, but if we can’t, we will just have to give it to the students. So, we propose actually building a physical model of the very model that we develop using a rubber balloon.  

Balloon Activity I Activity: Fill up latex gloves with water. Fill several latex gloves with different volumes of water

without bursting them. Hold it from the tip and see what happens.  This is a great visual representation of the pressure varying with the height, if this experiment is

successful. Students directly see that the pressure varies with depth.  Now, students can be asked to revisit the first exercise. What is the model that they should come up

with? We expect them to say that giraffes and snakes can be modeled by column of blood.  Interlude: What is blood pressure?

Instructor will give a discussion about blood pressure in human body. Distinguish systolic and diastolic pressure.

Using syringes and tubes, students will simulate blood circulation.  Blood Pressure Measurement

Fact: Nurses measure blood pressure on your arm, why not your calves?   Here they can actually make some quantitative predictions.  We might even have a few pressure measuring devices in the lab.  According to some sources, the modeling human blood vessels as a column of blood may not be so

simple, because there is a myriad of factors we are ignoring. (The blood pressure decreases as one gets further away from the heart due friction; there is no one single value for blood pressure (high and low; etc…) 

Tree Climbing Snakes vs. Non-Climbing Snakes: the Positioning of their hearts Fact: Tree climbing snakes have their hearts much closer to their heads than do non-climbing snakes.  At this stage, we expect students to work on coming up with explanations with models that they have

developed.  Balloon Activity II   

Activity: Water poured into a long skinny water balloon submerged under water fills up the balloon equally, e.g. does not cause stretching at the bottom. 

They need to recognize that pressure at the inner wall of the balloon is a sum of pressure from inside and outside. 

Tighter Skins of Arboreal Snakes in Comparison to Aquatic Snakes Fact: Tree-climbing snakes have slender bodies with tight skin while aquatic snakes have flabby

bodies with looser skin.  For a real demonstration, we can ask students to simply stand up and bend down to touch their ankles.

How long can they stay in that position? Not for long… This way they get the feel for what it feels like to have the pressure difference in the blood vessels. And they we can instruct them to imagine them selves in the same position in the water. 

More Challenging Observations Fact: There are more valves in the veins in the lower half of the body than the upper half of the body.  Fact: Astronauts, upon returning to earth, or patient laying down flat on bed for a long time, may feel

dizzy and can pass out.  Explanations of these facts may require a bit sophisticated application of the models that they have

built.  The phenomena discussed are more complex and it starts to look like the models are not all that useful anymore; it looks like we are forcing to emphasize the principle of pressure when it is not clear that it plays a distinct, central role in the phenomena under consideration.  

This is a perfect place to discuss the limitation of the model that we have developed.  What have we ignored? To what extent is our model valid? 

We can also discuss the strength of the model   Most importantly, we should end the lesson with a discussion of the usefulness/relevance of physics

principles in explaining biological phenomena.  Why are they useful and relevant? Hopefully, students will recognize that physics is worth studying.

  Version 2

  Learning Goals:   Short Term Learning Goals: Make explicit connections between physics principles and biological fact through model building activities:

1.  Identify relevant physics principles2.  Show explicitly how physics principles explain facts  3.  Use diagrams or pictures to aid explanation 4. Reflect on simplification of models that one develops

Long Term Learning Goals:

1. Make connections between physics principles and real life in general 2. Develop competence with more sophisticated model building 3. Appreciate the usefulness of physics in understanding nature

Lesson Design:

Previous Activities: The course is a standard first-semester calculus-based physics. They have just finished or concurrently learning about the basic fluid mechanics and dynamics, which typically comes after the entire mechanics section.

Lesson Overview: The lesson is for a 3-hour-long lab in an introductory physics course. First, students are introduced to the idea of model and model building in physics; but unlike Version 1, students spend a lot more time developing their ideas about what a model is by engaging in an actual model building activity first on their own, then with the TA and the whole class. Then, students start developing models of various physiological facts; but unlike Version 1, the number of models that they build are significantly reduced and the version allowed more time for students to develop their models.

Lesson Sequence:

Introduction (5 min)  Describe the general structure of the lab  Write and describe on the board the short term learning goals and how the lab will be graded (see

discussion of suggested grading procedure at the end of this guide).    Model Building Practice Session (30 - 40 min) 

Show demonstration of tightrope clown, with and without balancing arms.  Ask students, in their lab groups, to model the tightrope clown so that they can answer the question,

“Why does the tightrope clown stay balanced with the poles?  Why is it unbalanced without the poles?” (~10 min) 

Have each group put the models up on the board.  The TA should also have a model developed that he/she puts up on the board (it could be a pre-made model that every TA uses, for example something they made during the previous week’s TA meeting). 

With the whole class, discuss the features of the models they came up with.  In particular, discuss  The visual diagram they created  What aspects of the situation they chose to ignore  What physics principles were relevant  How they used these physics principles to answer the question 

With the whole class discuss the simplifications made in constructing the models.  In particular,  Whether those simplifications are reasonable  Possible improvements such as more explicit discussion of the physics principles and how

they apply.  Draw out and summarize the important aspects of model-building, referring to the guidelines for

model building (to be found in the worksheets) when necessary. Giraffe’s Skin (20 min) 

Tell students that from here on they are working individually in their small groups as usual.  Pass out a note card to every student.  Each student should come up with a possible explanation of the

giraffe fact and a physics principle that is relevant to their explanation on their own.  Collect the note cards, and redistribute the cards throughout the class randomly.  Every group should pick one idea out of the note cards they are given to develop further into a model. 

If they don’t like any of the ideas on the note cards they can use one of their own ideas.  Visit the groups and be sure that each model is complete, e.g. they identify relevant physics

principles, have an explanation of how the identified principle(s) helps explain the fact, have a diagram aiding the explanation and have a discussion of the simplifications made in constructing the

model.  Many students skimp on the explanation here – they don’t make the connection to the physics

principle explicit.  Pressure Thought Experiment (5-10 min) 

TA should go around the room, helping students with their misconceptions and misunderstandings of the diagram/setup. 

Students often believe that pressure is constant throughout a water-filled tube  Students often have not differentiated concepts of force and pressure  Students often invoke free-body-diagram by default in their explanations even when they are

irrelevant like when the problem is about pressure not forces on a single particle.  Latex Glove Activity (20-30 min) 

Be sure students hold the glove by the tied (knotted) end, with the tied off fingers pointing down.  If a glove breaks, fill up another by first tying off the fingers, then fill the glove with water until it

begins to noticeably sag.  Then tie off the end of the glove (this is actually easier with more water)  Students tend to easily get distracted trying to include the elasticity of the glove or include individual

forces on the glove.  Try to guide them to use the ideas of pressure from the previous activity.  Blood Pressure Measurement (40-50 min) 

See technical notes about the operation of the blood pressure machine.  If students do not use pressure variation with height as a physics principle when building their model

(part (d)), they will have a very difficult time coming up with a prediction.  Help them by pointing out this direction. 

Some students may feel that the model building exercise (part (d)) is repetitive at this point.  While the physics principles are similar to previous exercises, be sure to emphasize that it is how the physics principle explains the fact that is important.  Of course, that the same physics principles apply in all these different contexts is an example of how physics applies to the real world. 

Make sure that the diagrams in the model building exercise are sophisticated and actually help explain the fact. 

The model is best tested by comparing the P from standing and laying (because it maximizes the change in height), but some students are uncomfortable with laying down.  Tell the students that they may substitute sitting for laying. 

Part (f): Students always have a problem with conversions – be sure they’re converting to mmHg correctly! 

Part (f): Note that the estimated error in the measurements comes from the equipment error.  Part (f): Amazingly, some students merely estimate the height difference between the points where

they measure the blood pressure.  Remind the students that we have meter sticks for this purpose.  Part (h): Be sure students state whether the prediction agrees or disagrees with their measurement, and

that they include a discussion of why they think this.  Part (h): Students will have trouble coming up with a criteria to judge whether the simplifications they

made are valid.  They tend to go with their “gut” feeling.  The only criteria they have at their disposal currently is whether the model agrees with the measurements – if it does, then the simplifications seem reasonable and valid.  Of course, these are not the only criteria scientists use to judge the validity of assumptions, but they are the only ones available to the students at this stage.  The TA should engage the students in a discussion of the criteria if possible – the goal of this activity is for students to devote thought to judging simplifications and their model, not to get a “right” answer. 

Final Model (10-15 min) If students constructed a complete model using pressure at the beginning of the lab, they may feel this as repetitive. If that’s the case, they should use this opportunity as a chance to articulate their explanation, diagram, and discussion of the simplifications they have made. Go around the room to ask each group whether they have components specified in the guideline for model building: Does it identify relevant physics principles? Does it have explicit descriptions of how it explains the fact that needs to be explained? Does it have a diagram that aids the explanation? Do they reflect on simplifications their model makes?

Version 3

Learning Goals:

Short-term learning goals: Make explicit connections between physics principles and biological fact through model building activities. This means that students are able to…

Identify relevant physics principles Show explicitly how physics principles explain facts Use diagrams or pictures to aid explanation Reflect on simplification of models that one develops

Long-term learning goals: Make connections between physics principles and real life in general Develop competence with more sophisticated model building Appreciate the usefulness of physics in understanding nature

Lesson Design:

Differences between Version 2 and 3: The changes that we have made to the third version from the second version is minor compared to the changed made between the first and the second version. Here I describe the changes that are made. Refer to the appended worksheets for details.

Articulated our learning goals: In the previous lesson, we have emphasized that the aim of this lab is to connect physics and biology through model building. This meant that our short-term learning goals were a list of things that student should be able to do. In the version 3, we have identified each item on that list to be a component of model building. Therefore, we emphasized in the version 3 that the main learning goal is to learn what it means to build physics models of biological phenomena. This re-focusing of our learning goals helped students to be aware more explicitly that model building is the central piece of the lesson than they have been able to in the previous lesons.

Added explicit model-building framework: in order to facilitate even further students’ model building process we have added a box of framework (see below) in the student worksheets when we asked them to build models. The framework is intended to make explicit for students what needs to be included for an adequate model building.

Clarified language throughout: Based on student responses, we have identified several points in the worksheets where students did not follow through with model building. In order to communicate

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clearly to the students what they were being asked to do at those troubled spots, we have made the instruction more explicit throughout the worksheet. Refer to the appended worksheet for details.

Generated TA materials and TA training session on model building: because the labs are taught by teaching assistants, we needed to have a way to communicate to new groups of teaching assistants—as they change semester to semester—what the lesson is about and how the lesson should be conducted. Especially, instructors of this lesson needed to be clear about what the lesson meant by a model and model building. In order to facilitate the preparation of teaching assistants for teaching this lab, we have devised a detailed hand out for TAs and two hour-long training sessions. See the appended TA materials for details.

Finding alternative to borrowed blood pressure cuffs: This is a technical point. The automatic pressure cuffs that we were using in version 1 and 2 were borrowed from Biomedical Engineering Department, because, not knowing whether the lesson will continue to be taught, we could not justify the costs of purchasing expensive equipments ($1500 each). We have identified a much less expensive alternative ($80 each) now that we know we wanted to implement the lesson in regular introductory physics curriculum.

Rationale:

Why connect physics to biology? While the relevance of physics to biology may be obvious to experts, students often fail to see it, or, at best, understand the connection very naïvely seeing physics simply as a study of smaller units of nature. Helping students understand how physics is connected to the real world is not only an important goal of physics instruction, but also is becoming imperative as the nature of modern scientific research increasingly becomes interdisciplinary. While various efforts have been and are being made to help students grasp this connection, a focused, systematic study on how students might make this connection—knowledge that would be helpful in improving instruction on the relationship between physics and biology—has not yet been conducted. In this study, we attempt to illuminate challenges and difficulties students may have in learning this topic by constructing and conducting a single lesson that engages students in building a model that explains some physiological facts about various organisms using the concept of pressure and by closely observing how students respond to the lesson.

Why do the lesson as a lab? In order to engage students in model building, we needed much longer than the length of lecture or discussion periods. Needless to say, current introductory physics courses are already overcrowded with topics to be covered. The parts of the course that were most flexible were labs.

PART III: THE STUDY

Approach

We collected data of student thinking and learning via a variety of techniques designed to make student thinking visible. 

1) Observation of students. The primary task of the observers is to observe how students respond to the lesson and collect evidence on how well the students learned.  Observers take note the behaviors of the students and the benefits/difficulties of the lesson, NOT the behaviors of the instructor.  In particular, we directed observers to be sensitive to the following:

Lesson: Observe how students respond to a lesson in which they apply the physics principles of pressure to understanding biological function and structure in a model-building format.  Physics: As a result of the lesson, students should be able to understand how the principle of pressure is relevant to understanding various physiological facts about different organisms. More specifically, students should be able to: (1) provide real examples (2) provide quantitative analysis of their examples (3) recognize the limitation of the relevance (Primary Learning Goal).  Model: Be able to appreciate the broad relevance of physics to real life, build simple models using physics principles that explain some real-life facts, and evaluate different models based on their advantages and disadvantages (Developmental Learning Goal).

2) Individual Worksheets.  In both versions of the lab, students completed worksheets individually (although they worked together in a group).  In Version 1, the worksheets of the entire section (20 students) which performed the lab were collected and analyzed, while for Version 2 the worksheets of 30 students were collected as a sample of the entire class of 200 (the 30 selections were made by randomly choosing 2 worksheets to analyze from each lab).

3) Prelab worksheets.  In both versions of the lab, students were asked to complete a prelab worksheet and turn the worksheet in at the beginning of the lesson.  In Version 1, the worksheet contained a description, with examples, of what is meant by "model building" in physics, and 3 exercises, one of which asked students to build a model on their own for a given scenario, while the other two were given by a quantitative and qualitative question involving water pressure.  In Version 2 we only asked the students to build a model on their own for a given scenario.

4) Student perceptions and comments.  In Version 1 we collected student feedback about how they viewed the connection between physics and the real world both in the prelab and at the end of the lab.  Additionally, at the end of the lab we asked students to rate how confident they felt they achieved the learning goals of the lesson, and asked for general feedback and comments.  In Version 2 we only asked for student comments.

Findings:

Version 1 

1) Students were much more comfortable to use force in their models and lacked a solid conceptual understanding of pressure. 

It was quite revealing to see that students repeatedly employ the concept of force in constructing their models. In dealing with problems involving fluids, force is not a useful concept. However, most students used the concept of force to explain the various phenomena. For instance, drawing free-body-diagram (FBD)

was very common. In the latex-glove activity where students were asked to build a model that explained the shape of gloves, students identified forces like gravity, tension and normal force and drew them on their FBD.

Although most groups mentioned pressure as one of the relevant principles, they did not apply the concept to explain the shape of gloves; instead, they continued discussing how forces that they identified (like normal force and gravity) account for the shape. Students did not give up their models based on their FBD even when such approaches appeared unlikely to yield a satisfactory model.  Throughout the lab, the development of models based on forces was dominant, which reflected students’ comfort level with forces as well as their unfamiliarity with the concept of pressure. 

Some students came to the lab with a misunderstanding about pressure. In one of the pre-lab exercises meant to review the basic principle of pressure in fluid, students were asked to select a drawing that best represented the pressure exerted on the walls of a water-filled container. In their responses, 43% (6/14 responses) of the students chose the drawing that showed no variation in pressure with depth. Several students during the latex glove experiment also made factually incorrect statements such as “pressure is equal everywhere in the liquid”. Such conceptual misunderstandings contributed to their difficulty in building a model based on the concept of pressure and to their difficulty in connecting physics with biology. It is interesting to note that all students were able to solve correctly quantitative problems involving pressure in liquid from the pre-lab despite their misunderstanding about pressure. This finding is consistent with well-documented facts that students who do well in the course do not necessarily do well on conceptual assessments. 

2) Although most students were able to correctly recognize physics principles that were relevant for different situations, their models were often underdeveloped. 

In the giraffe example, for instance, one group recognized that gravity was responsible for blood pooling and therefore gravity was relevant to the variation in the tightness of giraffe’s skin. However, this group stopped at this stage in their model building. The group did not discuss or spell out how this relevant principle explained the fact about the giraffe’s skin. In fact, we did not observe any groups discussing in detail how the principles they identified explained the fact. Instead, many students used concepts as “buzzwords” to explain the facts without understanding the content of the buzzwords or their implications. When asked to provide visual representations of their models for the latex glove activity, students did not articulate how their drawings explained the observed fact that a water-filled latex glove bulges out more toward the bottom. They simply drew a figure representing the glove with no accompanying explanations. They seemed to think that identifying correct principles or drawing a simplified picture of the situation is the end of model building when it actually is the beginning of any model building. Students seemed to vaguely grasp that pressure is relevant to explaining most of the facts in the lesson, but they did not make explicit effort to make an explanatory connection between their model and the facts that needed to be explained.    

3) Students were too eager to accept plausible models without examining their limitations and weaknesses. 

Students did not exhibit much critical attitude toward the models that they developed. Throughout the lesson, students often accepted ideas put forth by a dominant member of their group. We observed several instances where a dominant student suggested an idea and the rest of the group members nodded or started to write down that suggestion on their worksheets. The criteria they used in accepting ideas seemed to be a mere superficial plausibility or an intuitive appeal, because we did not observe much discussion of how their ideas provided good explanations of phenomena nor any discussion of how their ideas may be flawed or limited.[8] In the blood pressure measurement experiment, students were especially uncritical about their models. Students compared the experimentally measured values of blood pressure in legs to the values predicted by their models. Most of them attributed the discrepancy between the two values to experimental error without having any estimate for the size of experimental error. These anomalies were explained away merely as deriving from imprecise measurement devices. Hence, they did not consider the possibility that the

discrepancy might derive from the inadequacy of their models. Throughout the lesson, students failed to exhibit explicit concerns to the limitations and weaknesses of models.

  We evaluated students' progress towards the learning goals by evaluating their answers to pre-chosen exercises with the help of a rubric (the design of the rubric was done with input from actual student responses).  Below are a set of “rubrics” – grading schemes for 4 chosen “checkpoints”, which are parts of the lab that, when graded, give a reasonably accurate indication of how well students met the primary learning goals.  The rubrics have been carefully designed – they were designed by analyzing in detail the responses from 30 (randomly chosen) students from a previous implementation of the lab.  Distinctions between different scoring levels correspond to different levels of achievement of the goals.  For each rubric, a simple “at a glance” criteria for a scoring level is given in bold as a way to quickly determine the scoring; just below this is a more detailed explanation of how to score this.  The number of students who obtained a given score is given in the last row of each rubric (with the exception of Checkpoint 3, which is special in that the grading is more qualitative and data here is not available).   The proposed grading procedure is for each TA to collect one worksheet from each group (each member of the group will then get the same grade).    The worksheets are graded according to the rubrics, with the point assignments:                                          Rubric 1  Rubic 1 addressed the student worksheet item on Pg 3, part b) :“In your group, use at least one of the notecards you’re given (or an idea of your own, if you can’t do anything with the cards you have) to create a model explaining the fact above.  A good model explains the fact based on some physics principles, with the aid of a diagram.  It is typically helpful to also explicitly list the assumptions you have made in developing your model.”   Goals of this Checkpoint: 

For students to include all of the aspects of a successful model.  Students should ground their explanation on a specific physics principle  Students should make an honest effort to connect principles and the fact.  Just explaining the principle

is not enough.  Some discussion of simplifications involved, with no judgement about whether these simplifications

are relevant or important, since the focus is on generating ideas, not necessarily “correct” ideas.   Four components necessary for a successful model  1.      A picture or diagram  2.      An underlying physics principle  3.      A written explanation of how the principle explains the fact  4.      A discussion of simplifications       

0  1  2  3  4 

Checkpoint # Maximum # of Points 1 4 2 4 3 3 4 4 Total:   15

No Answer  Answer lacks 2 or more components from above 

Answer lacks an explanation of how the principle explains the fact 

Answer only lacks a discussion of simplifications 

Answer has all major components from above 

Nothing is written, or essentially nothing is written 

The model is severely deficient and highly underdeveloped.  Little effort was involved in its creation 

A physics principle was mentioned, but an explicit connection to the fact was not made (or is not very clear) 

The model contains a decent explanation of how the physics principle explains the fact, but did not consider simplifications 

The model is well developed and has all of the major components above. 

Number of students who scored this:  0 

4  16  3  7 

   Rubric 2   Rubic 2 addressed the student worksheet item on Pg 6, part c) : “Based on the relevant physics principles that you identified, develop a model that explains the shape? In other words, explain why the glove is shaped this particular way.  A good model explains the fact based on some physics principles, with the aid of a diagram.  It is typically helpful to also explicitly list the assumptions you have made in developing your model.”  Goals/expected responses for this Checkpoint:

A picture or diagram Must identify that pressure increses with depth as a central physics principle. Must make explicit and valid connection between the physics principles and the fact (explanation

must make sense to an independent reader). Must identify relevant limitations and/or assumptions

0  1  2  3  4 

No Answer  Answer does not identify “pressure increases with depth” as relevant. 

Answer lacks an adequate explanation of how pressure explains the shape of the glove 

Answer only lacks a discussion of limitations or assumptions 

Answer has all major components from above 

Nothing is written, or essentially nothing is written 

Something has been written for the model, but it does not identify the variation of pressure with depth as a central component. 

The explanation does identify pressure as relevant to the explanation, but does not make the connection to explaining the fact as being relevant. 

The model makes an explicit connection between the variation of pressure with depth and the shape of the glove.  A discussion of Limitations or Assumptions is either lacking or not relevant, however. 

The model makes an explicit connection between the variation of pressure with depth and the shape of the glove, and contains a discussion of relevant Limitations and Assumptions. 

Number of students who scored this:  0 

12  11  1  6 

   Rubric 3  Rubic 3 addressed the student worksheet item on Pg 12:“By drawing on the examples from this lab, construct a model that explains the fact about the giraffe's skin.”   Goals for Students for this Checkpoint: 

To be explicit in the connection of the principle of the variation of water pressure to explain the giraffe fact. 

To construct a picture which meaningfully connects the idea of the variation of water pressure with depth to the giraffe fact. 

    

0  1  2  3  4 

No Answer  Explanation does not involve pressure at all. 

Model involves pressure, but explanation not explicit 

Picture is not meaningful.  Model involves pressure and explanation is explicit 

Model has an explicit explanation of how pressure explains the fact.  The model contains a meaningful picture. 

No answer is written – the section is not completed 

The student’s explanation does not involve the concept of pressure variation with depth at all.  This is a primary point of the lab, so if they do not use this concept the student is not rated very highly. 

The student’s explanation involves pressure, but does not make the connection of this concept to the fact explicit, but rather makes jumps in their reasoning.  Since a desire for students to be explicit is one of the stated goals of the lab, students not meeting this criteria are not rated highly. 

The student’s explanation involves pressure and is explicit in their connection to the fact.  However, the picture which accompanies the explanation is not “meaningful”, in that it does not clearly represent the physics concepts explained in the explanation.  Since an explicit connection is a primary goal of the lab, students are rated highly. 

Same as (3), but now the picture is meaningful.  This meets all of the goals for this activity, so students are rated highly. 

Number of students who scored this:  0 

5  15  4  6 

     Common problems for why students’ explanation is not explicit: 

Stated that “pressure is high” in leg, but not explained why, or what “high” pressure is relative to.  Stated that “pressure is greater in leg, thus skin must be tighter”.  This is not complete – why must the

skin be tighter?  Did not recognize why the skin must be tighter in the leg, e.g. should note that all of the blood rushing

to the legs is a bad thing physiologically. 

Discussion:

The results of our study suggest that students encounter several difficulties and challenges when learning how to make connections between physics and biology. In what follows, we will describe these problems and our solutions. The solutions broadly fall into the categories: Address misconceptions; provide feedback and framework to students; and provide TA training and materials.

One of the most important challenges that can affect a student’s ability to achieve the learning goals in this lesson is a lack of a conceptual understanding of water pressure. As explained in the findings, we found that students in Version 1 of the lesson had serious basic misconceptions and misunderstandings of pressure. Without a solid foundation in this concept, students were unable to successfully make connections to biology through building physics models. This is a specific example of the more general problem in which if students do not have a solid conceptual foundation of content, then it is difficult for them to employ features of scientific, critical, and higher-order thinking. Our solution (Versions 2 and 3) is to ensure students have a solid foundation in the concepts before engaging in higher order skills by addressing their misconceptions in a pressure activity in the lesson designed to draw out their thinking. A TA guide provides information for common misconceptions students have, which can be addressed during the activity designed to draw these issues out.

Another difficulty we observed is that students tend to leave their models underdeveloped, including only superficial explanations and discussion. Again, this finding is part of a broader context in which students tend to have a superficial understanding of how biology and physics are related, as we observed in a prelab survey where most students indicated they viewed the connection between physics and biology as an intellectual or reductionist hierarchy. Providing students with detailed feedback on model building, through the prelab and the TA-led activity at the beginning of the lesson (Versions 1 and 2), as well as a clear framework for model building (Version 3), led to improved conversations among student groups about model building.

We found that the above solution also helped with another common problem of students in which they tend to not reflect on the models that they build. Providing TA feedback to students on how to engage in the reflection process (through the TA guide and TA training) as well as building reflection directly into the framework for model building helped students recognize the importance of reflection as part of the process of making connections.

In Version 2 we used the rubric scoring system to evaluate whether students met the goals of the lesson. The rubric is designed so that students scoring in the top two levels of the rubic (3/4 or 4/4) have met the learning goals. We found that of the 30 total students selected for analysis, 10/30, 7/30, and 10/30 scored in the top two levels for Rubrics 1, 2 and 3 respectively. This suggests that approximately 33% of the students met the learning goals designed for the lesson.

Based on these results, in Version 3 we provided more opportunities for feedback and a framework for students to use in building models, which we expect will lead to more students achieving the learning goals. Unfortunately, due to time constraints we were unable to collect rubric data for Version 3. It would be interesting to study students’ rubric scores for Version 3 to see if the intended revisions, providing more feedback and detailed frameworks, helped students achieve their learning goals.

References   Black, Paul and Dylan Williams, 1998. Working Inside the Black Box: Assessment for Learning in the Classroom. London: King’s College London. 

Cerbin, William and Bryan Kopp, 2006. Lesson Study as a Model for Building Pedagogical Knowledge and Improving Teaching. International Journal of Teaching and Learning in Higher Education 18, Number 3, 250-257. 

deJong, T. and M. G. M. Ferguson-Hessler, 1986. Cognitive structure of good and poor novice problem solvers in physics. Journal of Educational Psychology 78, 279-288.  

Denny, Mark W. 1993. Air and Water: The Biology and Physics of Life's Media. Princeton University Press. 

Fernandez, C. and M. Yoshida, 2004. Lesson study: A Japanese approach to improving mathematics teaching and learning. Mahwah, NJ: Lawrence Erlbaum Associates. 

Hammer, David, 1995. Epistemological considerations in teaching introductory physics. Science Education, 79(4), 393-413. 

Heller, P., Keith, R., and Anderson, S. 1992a. Teaching problem solving through cooperative grouping, Part 1: Group versus individual problem solving. American Journal of Physics 60, 627-636.  ———. 1992b. Teaching problem solving through cooperative grouping, Part 2: Designing problems and structuring groups. American Journal of Physics 60, 637-644. 

Larkin, Jill H., John McDermott, Dorthea Simon, and Herbert A. Simon, 1980. Expert and novice performance in solving physics problems. Science 208, 1135-1342. 

Lising, Laura and Andrew Elby, 2005. The impact of epistemology on learning: A case study from introductory physics. American Journal of Physics 73, 372-382. 

National Research Council of the National Academies, 2003. BIO2010: Transforming undergraduate education for future research biologists. Washington, D.C.: The National Academy Press. 

Redish, Edward, Richard N. Steinberg, and Jeffery M. Saul. 1998. Student Expectations In Introductory Physics. American Journal of Physics 66, 212-224. 

Van Heuvelen, Allan, 1991. Learning to think like a physicist: A review of research-based instructional strategies,” American Journal of Physics 59, 891-897. 

Wiggins, Grant and Jay McTighe, 2005. Understanding by Design: Expanded 2nd Edition, Alexandria, VA: Association for Supervision and Curriculum Development.

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Appendix

List of contents

1. Observational Protocol for version 1: The observational protocol used by the observers for Version 1 of the lab.

2. Section-by-section analysis of the observations and student worksheet data for Version 1

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Observational ProtocolThe goal of the project is captured in the three goals below:

Lesson : Observe how students respond to a lesson in which they apply the physics principles of pressure to understanding biological function and structure in a model-building format.

Physics: As a result of the lesson, students should be able to understand how the principle of pressure is relevant to understanding various physiological facts about different organisms. More specifically, students should be able to: (1) provide real examples (2) provide quantitative analysis of their examples (3) recognize the limitation of the relevance (Primary Learning Goal).

Model : Be able to appreciate the broad relevance of physics to real life, build simple models using physics principles that explain some real-life facts, and evaluate different models based on their advantages and disadvantages (Developmental Learning Goal).

Your primary task as an observer is to observe how students respond to the lesson and collect evidence on how well the students learned. Please note the behaviors of the students and the benefits/difficulties of the lesson, NOT the behaviors of the instructor.

Please take notes on your group’s behavior. All observations will be used to determine how students respond to the lesson.

Here are the general observations you might make. Please try to observe the context in which you make the observation.

In order to observe… You might look for…

Misconceptions Wrong applications of the concept of pressure

Derailing of the Lesson Expressions of boredom

Conversations unrelated to the lab

Group Dynamics Dominant students vs. passive students

Lazy students letting everyone else do the work

Respectful exchange of opinions

Engagement Continued effort in the face of difficulty or confusion

Requests to know more about the subject

Spontaneous expressions of interest or curiosity

Expressions of excitement

Problems with understanding directions in the lab

Expressions of confusion about what they are supposed to be doingSigns of frustration

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Here are some specific observations you might make to decide to what degree students achieved their learning goals. Look for examples and evidence that students understand (or are able to explain) how physics principles such as pressure can be applied to biological phenomena:

Do students recognize that the concept of pressure may be important for understanding various physiological facts (e.g. do they mention it in their discussions)? If not, what difficulties are they having? Physics

Do students use the idea of pressure when constructing explanations of observations? If not, what difficulties are they having? Physics

How well do students use the idea of pressure when constructing explanations of various facts (quality of their explanations)? Physics

Do students use an appropriate example of the concept of pressure? Do they use it in a novel context? Physics

Do students explicitly or implicitly use the concept of pressure to make a prediction from a model or explanation? Physics

Do students use equations or diagrams related to pressure when constructing explanations or making predictions? Physics

Do students reflect on the models that they develop? (Do they say things like these? “I don’t see how these two parts fit together.” “We need more information before drawing any conclusions. ” “I still don’t get this.” Physics, Model

Do students use explicit standards to evaluate their own models and compare with alternative models? Physics, Model

Do the students integrate previous examples of model building or previous knowledge about physics in constructing their own models? Model

Do students recognize the value of making predictions from existing models? Model

How comfortable were the students in coming up with explanations/models at the beginning of the lesson? At the end of the lesson? Were there any improvements or changes in how they constructed models? Model

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Section-by-section analysis of the observations and student worksheet data for Version 1

What’s a Model? (Discussion)

Observations: Students were passive Students unsure what was asked of them Students worked on their own first, waiting for someone to break the ice. Reluctant to immediately

interact. No specific instruction to talk to neighbors Possible interference from observers Goals of the lab didn’t seem to sink in, weren’t made clear. Blank stares. Didn’t explicitly mention prelab Student responses of “What’s a model” seemed to draw heavily upon the prelab Student examples of models did not seem to draw on the prelab

What were the goals of this activity?: To get students to think about what model building is and entails, and provide examples of models. To have students draw upon what they learned from the prelab.

How/Why did the students meet/not meet this goal?: Students did think about what a model is, as evidenced by written work. However, few students vol-

unteered to share ideas. It was unclear if all students understood the major features of model building. Students provided examples of models in written work. Students used the definition of a model from the prelab, but not examples of a model from the prelab.

Recommendations for modification: Start with a question, e.g. “Model this scenario…” Make sure that the focus of this activity is about the ideas of the students, not the ideas of the instruc-

tor (instructor is acting as a facilitator, don’t need to know his/her ideas). No lecture, no telling the students things.

Make explicit connections to their work in the prelab, explicit connections to model-building features in the prelab.

More explicit mention of the learning goals. In discussing models, make it explicit that a model is almost always accompanied by a picture which

displays the relevant physics principles being used.

Giraffe Fact (Discussion)

Observations: The materials on the table seemed distracting One group immediately jumped to blood pooling, but didn’t spell this out. Others in the group ac-

cepted this without question. “Gravity pulls blood down” Vocal student eager to get answer. Started questioning the validity of the fact Discussion stimulated interest. Students seemed puzzled by the fact, were enjoying the activity. Hypotheses centered around the ideas:

o Pushing/pumping up bloodo Helps when walking through bushes/less drag

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o Prevents fluid poolingo Support weighto Primarily muscle

Physics principles discussed:o Gravityo Pressureo Young’s Modulus/Straino Elasticity

No discussion or thought of how the physics principles are relevant.

What were the goals of this activity?: Primary objective: Hook students by involving them in the model building process, coming up with

their own hypotheses. To help students be creative and excited, interested in this fact which will be used throughout the lab. Get the students to start thinking about observations in terms of physics principles.

How/why did the students meet/not meet the goals?: Engaged some students, but left others very passive. All students were at least writing their hypotheses. Some students not (culturally?) familiar with free-thinking exercises. Group dynamics is very important for meeting the outcomes of this exercise

o Influence of the “leader” is strong, limiting other ideas and discussiono Little input from passive members or passive groups.

Recommendations for Modification: Emphasize creativity Notecard exchange: every student takes 3 min on their own – no talking to neighbors – to write an

idea to explain the fact on a notecard. Cards are collected by the TA, shuffled, and redistributed anonymously. Groups discuss the ideas other students wrote down, discuss the physics principles rel-evant to the idea. This emphasizes student involvement in the generation of ideas, gives passive stu-dents time and room to reflect and think, and reduces impact of group dysfunction on the initial gen-eration of ideas.

Latex Glove (Activity)

Observations: Students could follow the procedure Delay/bottleneck in filling the gloves. Unused time. Student ideas:

o Pressure – not mentioned in some groups until TA brought it upo Normal Forceo Old Peopleo Spring constant

Some students “stealing” other group’s ideas, looking for buzzwords to use like \rho g h. Everybody sketched the shapes correctly. Thinking in terms of forces was prevalent and persistent, but no detailed quantitative analysis was

done (although some students did draw a FBD). Students were concerned with balancing forces, but

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didn’t address where the forces were coming from. Students persisted with these ideas even after re-alizing they were not good concepts for describing the shape.

Misconceptions about pressure: Equal pressure in the liquid. Reference to figure skater model in model building exercise. Some groups started to get frustrated when they couldn’t “figure it out” and kept going over the same

unuseful ideas. In one group the dominant student was suppressing the other student who wanted to slow the pace of

the discussion. Students were engaged in the discussion; lively. Some groups independently came to the realization that the gloves could be seen as skin, but others

didn’t even mention the giraffe at all! All students used gravity and/or pressure in their explanations of the shape to varying degrees. Some

mention elasticity as a reason for the shape. Students became very confused when comparing to the glove on the table. Students not sure about how to apply and visually represent pressure. Don’t know how to work with

it. Most students made a connection with the giraffe.

What were the goals of this activity?: To get students to draw the expected model picture, recognize the importance of pressure in con-

structing this picture. Make explicit connections to understanding the giraffe fact.

How/why did students meet or not meet the goals?: Laying the glove on the table was a major distractor, seemed to prompt many students to begin to

think in terms of forces (normal forces, etc..). One water spigot created discontinuity, upset the momentum of interest from the previous activity. Student responses to earlier exercises seemed to suggest misunderstanding of applying forces/pres-

sure to the shape of the glove, but responses to applying this to the giraffe suggest understanding. Two interpretations of this are:

o Students do not understand the application of pressure in this context, but are still able to an-swer questions correctly.

o Students are driven to correct understanding by the comparing what they learned to the gi-raffe, external contexts.

It is unclear with the data we have which of these interpretations is correct.

Recommendations for Modification: Have pre-filled gloves Have the students only make observations of the glove while holding it in the air, focus on the ex-

plaining its shape (e.g. “change in shape” confused them). “Draw simplified picture which explains the shape” in bold in the worksheet. Have students explicitly build a model of the giraffe using what they learned. Insert picture of a gi-

raffe’s leg, and ask for a model of it.

Blood Pressure – Systolic/Diastolic (Activity)

Observations: Students were not reading instructions carefully – tired, getting antsy. Not pumping the syringe, just pushing down as hard as possible on plunger.

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Confusion among students between systolic/diastolic Some students just rushed through, didn’t discuss. Students had a hard time getting the equipment to work – getting the plunger in the syringe is diffi-

cult. Student thinking on systolic/diastolic was not visible.

What were the goals of this activity?: To understand what systolic and diastolic pressure are in order to decide which is more relevant to the

subsequent activity.

How/why did students meet or not meet the goals?: Students did not meet this goal.

o There was 1 whole page of text! Students were getting restless, bored, unfocused.o Point of this activity not made clearo Started to run out of steam – have been thinking for an hour already.o Simulation activities didn’t add to understanding of systolic and diastolic pressure – students

weren’t sure what the most important part of the simulation activities was (e.g. feeling the pressure in their fingers) among all the instructions.

Recommendations for Modification: Take out activity entirely. Modify systolic and diastolic explanations to make systolic more obviously the relevant choice for the

subsequent activity by emphasizing the role of elasticity of the artery in the diastolic measurement. Modify systolic and diastolic explanations by emphasizing that this is what the blood pressure cuff

measures as systolic/diastolic, not what these pressures “actually” are defined as.

Blood Pressure Measurement

Observations: Increased instances of hand-waving arguments, increased frustration with lesson, “whatever,” stopped

inputting effort. No explicit mention of pressure, just typically gravity, in discussions (Shusaku) Student comment: “Measured on arm, because it’s level with the heart.” Mathematically proficient in using p = rho g h (Shusaku) Lots of lost time while students were taking the measurements. Other groups got anxious when they saw the advanced progress of other groups in the lab. Some groups didn’t make the connection of measurement to their model of human blood pressure.

Perhaps didn’t recognize the significance of the prediction. Didn’t discuss why diastolic was not the correct choice. Attributed differences between measurement and prediction to error, not a failing of the model. Able to connect observations to the giraffe after being prompted. Some groups predicted blood pressure should be higher in the arm because it’s closer to the heart. Physics principles discussed: blood viscosity, radius, constant force (?). Some groups did not recognize that P = rho g h is in contradiction with higher blood pressure in their

arm – made it so that above formula predicted that blood pressure was higher in the arm. Some students had some difficulty in unit conversion. Larry’s group didn’t know how to make prediction, got stuck for a large amount of time.

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At least one group could not construct a model and make a prediction; one group had to force physics concepts to conform (incorrectly) to their expectations, but never reflected on the discrepancy. Other groups seemed able to construct the models correctly with little or no instructor help.

No discussion of criteria of comparison to the model, but everyone seemed to agree that the measure-ment agrees with pressure due to gravity.

At least 5 students successfully make the connection to the giraffe, but others did so only superfi-cially.

What were the goals of this activity?: To have students create a model and test it with blood pressure measurements To have students make a quantitative prediction using the expected model. For students to use a simple model based on the principle of pressure due to gravity and be able to ex-

plain how it is relevant and applicable to explaining variations of human blood pressure.

How/Why did the students meet/not meet the goals?: All groups (except 1) were able to make a quantitative prediction based on a model. Some groups did not come up with the expected model and others made quantitative predictions not

directly based on the model. Some students were able to recognize the importance of pressure due to gravity but couldn’t apply it:

o One group predicted the blood pressure would be higher in the arm using the equation P=rho g h because they wanted their quantitative prediction to match their qualitative prediction that pressure is higher closer to the heart.

Students did not demonstrate an understanding of the applicability of the concept of pressure due to gravity, except when using the equation P = rho g h.

Most students were able to use a simple model based on the principle of pressure. There is not much evidence that students discussed the limitations and relevance of their models.

Why?o It is possible that students’ obsession with the “right” answer hindered their ability to be criti-

cal about the model and its simplifications after they got an answer that was close to the ex-pected answer.

o Students were not prompted directly to do this.

Recommendations for modification: Reorder the activity in the following way:

o Qualitative prediction directly after the presentation of the fact.o Measurement of blood pressureo Does you qualitative model roughly agree with this?o If so, do a quantitative calculation using your qualitative model, compare to the measuremento Explicitly discuss the simplifications and limitations of the modelo Apply to further your understanding of the physiology of the giraffe.

Simplify “measurement” text, reduce the number of question marks.

Tree Climbing Snakes

Observations: Student motivation dropped off after blood pressure measurement Students made connections to dinosaurs and their height differences Most students noticed pressure and gravity are relevant physics principles for the physiology of

snakes.

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Almost all students made the connection with height difference between the head and heart in a gi-raffe (also dinosaurs in some groups).

Most groups finished this activity very quickly (under 10 min?).

What were the goals of this activity?: For students to build a model using pressure due to gravity and understand how the model helps them

explain aspects of snake physiology (e.g. the placement of the heart). To practice physics modeling skills To provide students with yet another example of how physics affects biology. To make connections between previous activities.

How/Why did the students meet/not meet this goal?: Almost all students (except for one [student 10]) correctly identified the physics principles involved. It is unclear from the model pictures if the students understand how the model helps them explain the

physiology (due to a lack of visible thinking). All students identified correct principles and drew simplifications and identified important aspects of

simplifications, but it was unclear if they understood how the model explained the desired fact (e.g. it was not explicitly prompted in the worksheet).

There was no data on how students viewed connections between physics and biology All students were able to make connections to previous activities and some constructed further exam-

ples.

Recommendations for modification: Need to be more explicit in having students explain how their model explains the fact or system of in-

terest. Without direct connection to the previous activity, it’s not clear what the role of this activity is. Use this as a quiz (with more explicit instructions)?

Glove in Water

Observations: Revitalized the discussion One group just watched the others perform the experiment. Physics concepts mentioned: weight, buoyancy, force. Students were more comfortable thinking in terms of forces. Students didn’t discuss how the physics concepts lead to a change in shape. Student comment: “Change in pressure in water is negligible” Almost all students incorrectly explained the change in shape. Common responses were:

o Buoyancy counteracts gravityo The pressure fro buoyancy pushes on all sides equally.

What were the goals of this activity?: For students to transfer their understanding of how pressure varies with depth to explain the shape of

the glove submerged in water. For students to understand that immersion of an object in water provides a variation in external pres-

sure with depth.

How/Why did the students meet/not meet this goal?:

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Almost all students failed to understand that immersion of an object provides a variation in external pressure with depth, as evidenced in their responses about the change in shape. Why? Students were unprepared to consider explanations of this type, and a complete understanding of this phenomenon is very challenging.

Transfer of understanding of pressure did not occur, as shown by rampant use of forces and incorrect explanations of the shape. Why? It appears this is largely because students did not have a well devel-oped model from previous exercises.

Recommendations for modification: More careful consideration is needed about the expected visual representation of pressure (e.g. is

pressure a vector?) This activity may not be suitable for students without a mastery of the concepts of pressure variation

with depth Recommend cutting this activity entirely.

New Outline for Lesson

Model Building:o Exampleso Construct Visual representations

Giraffe fact Thought experiment: glass tube with springs in the sides – sketch the position of the springs from the

pressure from the water Glove/Ballon activity

o Construct visual representationo What needs to be done to restore the shape?o Think back to the giraffe

Nurses/Human Blood Pressure Discussion of connection between biology and physics End