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My Take on Learning from Laboratory Activities

January 7, 2018

This week, a lot of folks on twitter were discussing a paper in Physics Today by Natasha Holmes about the shortcomings of laboratory instruction. I’m not going to specifically get into the details of this paper here, but it was the stimulus for me writing this blog post. It’s a good read, and you should check it out if you haven’t. Anyway, based on my earliest experiences in Physics Education Research, I am not the least bit surprised that it is a typical outcome for most contexts of physics laboratory instruction to have little or no impact on student learning of physics content.

Why am I not surprised? (Spoiler: students can struggle to recall even the outcome of many lab activities, let alone any concepts or principles that relate to those activities.)

Here’s an example from my very first research project while I was a graduate student at Arizona State University. Students in an introductory college physics course would take a traditional laboratory at ASU that was separate from lecture. Each week students collected data (often using vernier equipment) about a different physics topic, plotted various data, and verified that results were consistent with theory. One week after students completed any given lab, I administered a post-test of some sort, related to the topic. What I learned fairly quickly is that you didn’t need to be very tricky with your questions. Often the best ones literally just asked students to state back what they had observed in the lab.

For example, for a lab on projectile motion, students use a photogate to measure the initial speed of a horizontal projectile (rolling off of a lab table), and also use a timing pad to on the floor measure time of flight. Students observed that the time of flight was independent of speed and that the horizontal distance was directly proportional to the initial speed. Students were asked to make plots of this data and also to answer questions

So the next week, the post-test survey I administered asked students to rank the time of flight for three experiments – ones that left the table with speeds v, 2v, and 3v. Some students got a slightly different version of the ranking tasks which was to compare the time of flight for landing at horizontal distances x, 2x, and 3x. The questions included drawings of the situation that basically mimicked their lab experiment. Usually about half of the students could correctly answer such questions after the lab.  (Note: my experience with this data led me eventually to a more careful study of how students were answering these and other similar questions).

Conclusion: If one week later, many students cannot remember the results of these types of labs, we probably don’t stand much of a chance of them learning, remembering, and being able to apply any underlying principles that the lab result was intended to support. Right?

What’s wrong with labs? (Spoiler: It’s not labs per se that matter, but how and whether laboratory activities become relevant objects in broader discourse of students’ learning)

So, the truth is this. I actually do think that laboratory activities can play a supporting role in students’ understanding of concepts, including enhancing students’ ability to transfer those concepts to novel situations. That said, lab activities alone are pretty useless and irrelevant. What matters more is the broader context in which a lab resides, and even furthermore I would say its how students “frame” the role of lab in the broader context of their learning.

So how might I judge whether a laboratory activity I’ve planned is playing a meaningful role in students’ learning? The most crucial thing I look for is what happens in the coming weeks. If we as a class never explicitly mention a lab during ongoing discussions–what we saw, what we concluded, or what it meant– that lab was likely meaningless. That’s it. That’s really my only criteria. I don’t mean the lab was inherently meaningless. I mean that our subsequent activity rendered that lab activity meaningless, retrospectively. In trying to improve things for future courses, it could be that I need to ditch the lab, or it could be I need to better plan for how that lab will be continuously rendered meaningful through subsequent activity, or I need to help with reframing lab.

Lab activities I just do not think have any inherent value, just as activities of mining raw materials has no inherent value outside a broader activity. It’s what happens subsequently in a process that determines it’s value.

Brian, what the heck are you talking about? (Spoiler: here are some examples to help clarify what I mean)

Newton’s 2nd Law Lab:

On twitter recently, I tweeted about a Newton’s 2nd Law lab that I have adapted and refined over time, which is basically just a half-atwoods with force sensor on a cart and motion detector. In that lab, I deliberately have students in class take data using a 1.0 kg mass. A twitter friend of mine remarked that he might be worried that this could accidentally reinforce a misconception about how force and acceleration are related (i.e., F = a). I agreed that this seems like a possible outcome, but perhaps only if you are looking at this lab in isolation and expecting students to “discover”, “abstract”, or “generalize” the correct ideas from it. But that’s not how I look at this lab (or most labs), I look at this lab as something designed for talking about later, to uncover its meaning through subsequent activity. Specifically, I aim for students to start thinking of net force as meaning something like, “It’s the kind of (collective) forcing that would cause a 1.0 kg object to accelerate at the same value.” We expand from that specific lab by thinking about data / experiments for objects that are heavier and lighter with in-class clicker questions and post lab questions. But most importantly, it’s something I try to work into lessons during every single day in following weeks while we solve force problems. If I am doing an example problem, I won’t merely use the equation Fnet = ma. Instead, I will calculate Fnet and talk about what that means for a 1.0 kg object, what that should mean for our actual object, and figure out exact values using proportional reasoning. If I want to be really explicit, I might make an acceleration vs. force graph similar to lab. Similarly, when students are working problems at whiteboard, I expect students to always explicitly determine a net force value, and I ask questions about what that means, for a 1.0 kg object, for their actual object, and often other masses. I ask, how do they know? Why does it make sense? What observations have we made that support that way of thinking about how objects respond to forces?

Friction Lab:  I have also developed some friction stations that I think are a pretty decent introduction to the topic, but again, the question isn’t if a lab is good or bad by itself. One of things I expect out of this lab is for students to spontaneously bring up stations from that lab when we get stuck on a problem or a clicker question about friction. One clicker question in particular where I see this happening is about pulling objects at angles along rough surfaces. The particular clicker asks students how the angle of the pull might affect how easily the object budges. In this clicker question, there are certain lab activities I am looking for students to reference during discussion, including observations about normal force,observations about the effect of normal force on friction, and observations about angled vectors and components. 

How do you get students to treat labs as activities relevant to future discussion? (Spoiler: treat them as if they are actually relevant to future discussions and plan for later activities that are designed to make use of that relevance).

So, I don’t think there is one answer to this, but you certainly don’t just hope it happens. Here are three concrete things you can do to help support it, but there are many more.

  1. Make sure that laboratory activities are meaningful to prior discussions. Many times students don’t know why they are doing a particular lab, or how it’s connected to their prior learning. By making sure students have a sense of purpose and connectedness with lab before hand, this makes them more likely to extend that connectedness in the future. Some of the ways I do this are following: using clicker questions to raise an issue (scroll to end of this post to see an example from forces), using demos to establish a tentative result and present a challenge (Newton’s 3rd Law), or sequencing questions, activities, and discussions that help us refine an understanding through observation and testing (circular motion). It’s a good sign when students can say why they are doing something and/or what they are trying to figure out.
  2. Ask questions, use prompts, and phrases that imply connectedness and expansiveness. (What will you want to remember about this lab tomorrow?, How is your answer to this question supported by what we observed earlier today? How is this result similar or different than what we saw before? How does this observation change your thinking about? How does this outcome influence our answer to the question of ___? What ideas from today’s lab will be helpful when you go to ___ ?  ). If you are interested in this more, see this paper about expansive framing and transfer.
  3. Design (writing) activities that require students make use of observations from lab activities as evidence in making claims about ideas. Here are some examples of students referencing lab activities about light in a course of I taught:

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Important Things

December 21, 2017

A few things I’d like to get back to doing in the spring that I didn’t have the mental energy / time for this past fall.

1. Making the first assignment of the semester to find my office and say hello.

2. Emailing students who miss class to let them know we missed them (same day)

3. Holding office hours in varied places such as

  • Empty classroom
  • Library
  • Coffee Shop
  • Science building lobby

4. Early on, giving students a survey about their learning and performance goals in this class, and later checking in with students who are not meeting their own goals.

5. Instead of suggesting vaguely that students come to office hours for extra help, actually sit down with them and schedule a specific date and time that works for both to meet.

6. Set aside time on day one to help students structure their weekly study schedules and semester planning. Follow up with students who are no getting it done to revisit the schedule.

Behavior, Attention, and Emotional Regulation in Changing Teacher Talk Moves

December 11, 2017

Every time I visit new physics teachers, I am reminded of just how much skill goes into pulling it off. So this is just a ramble of some of what I was thinking about this weekend after a visit with some new physics teachers.

So, one of things we learn about in our learning assistant seminar regards different types of classroom discourse. We talk about IRE or triadic dialogue (Teacher Initiates with Question, Student responds with a short answer, and Teacher Evaluates the appropriateness of the answer). We also talk about alternative talk moves that can help move us toward more productive dialogue (e.g., probing, pressing, re-voicing, prompting for more participation, etc).

Behavior: What a Teacher Says

From a behavioral perspective, there are a few reflexive habits that can pull a teacher into an IRE type dialogue with a given student, even if it’s not necessarily their intent. One such reflex is to “praise” students. The student provides some answer which is deemed appropriate and a natural response can be to immediately say back “Great!”, “Good”, “Excellent!”. A desire to be encouraging combines with a lack of alternatives to create a strong pull into this type of discourse.

Knowing that new teachers are likely to have this habit, I find it important to have them practice and rehearse new talk moves, which can help override the praise reflex. I try to limit the new talk moves to 2 or 3 phrases that the teacher can over practice to the point of becoming habit. I usually pick variations of the following to start:

  • “Can you say more about that?” (probing)
  • “Can you tell everyone why that answer makes sense to you?” (pressing)
  • “So ___ seems to be  saying ____. Who would like to add on to what ___ said?” (re-voicing, and prompting for more participation).

Talk moves are important, as they provide model alternatives for students to practice. It gets them behaviorally orienting to a new way of responding. But behavior is not enough, because behavior is often driven by attention.

Attention: What a Teacher Listens For

Often what drives a teacher to enter in IRE dialogue is not just a reflex to some objective external stimuli, but rather it is a response based on how attentional resources are allocated.

For example, if a teacher is listening to student contributions by paying close attention to the correctness or appropriateness of the students’ responses, it is somewhat reasonable for the teacher to respond in a way that concerns its correctness. We might think of this as the teacher having some idealized response(s) in mind, and the teacher is listening to the students’ response to see how closely it matches these for not. If the response matches closely to the expected correct response, the teacher might say, “Great!”. If the response does not match, they might say, “Well, not quite,” or “That’s close, but…”. There are of course a variety of other more responses about appropriateness of the student responses that aim to be more or less encouraging,  more or less neutral, or  more or less discouraging.

From this perspective, it’s important to not just change the behavior of the teacher. What is important is to help them focus on different aspects of student talk. There are so many things a teacher can attend to in students responses, and I don’t want to get into all of them. For the very new (apprenticing) teacher, my goal is to help them listen to student contributions from the perspective of: “Do I understand what the student really means? Do I have a decent sense for what they are thinking? OR Did I not yet quite know what the student means, why they said what they did, and they are thinking?” Attending to student contributions from this perspective more naturally leads to following types of responses: If I don’t understand what the student means, I should ask them to either say more (e.g., probing) or ask them why they think that (e.g., pressing). If I do understand what the student means, I might test my hypothesis that I understand by re-voicing what they have said back to them. Of course, this way of attending to student thinking is inadequate for all the ways of a teacher must attend to student contributions, but it serves as the point, that how teachers are likely to respond is based on how attentional resources are allocated.

This requires a lot of practice and modeling–to help new teacher get a sense by what we even mean by “what the is student thinking”, and importantly what it feels like when you think you understand a students’ thinking.

Emotion: How a Teacher Feels About What They Hear

Attention is driven in part by emotional states. It is common for the new teacher to experience a pleasant emotional state when students say correct things and to experience some level of discomfort when students say incorrect things. If a new teacher’s own emotional state is strongly impacted by the correctness of student contributions, it makes sense to allocate attentional resources on the correctness of student thinking. If the contribution is correct, the reward center of the teacher’s brain is activated. If the contribution is incorrect, the teacher experiences activation in the pain center of their Brain, and they act to alleviate this pain by perhaps correcting or quickly leading the student to a correct answer.

A second layer that exists is this– students that are used to being immediately praised or corrected, feel discomfort when they are not immediately praised or corrected due to the fact that they don’t know where they stand. Teachers can pick up on their students’ discomfort and themselves feel uncomfortable about their students’ discomfort. The teacher and the student will act together to alleviate everyone’s discomfort. Thus, the teacher and the student may steer the Dialogue toward IRE as a quick way to alleviate each other’s internal suffering.

From this perspective, if we want to change the teacher’s attention (i.e., how they listen and what they listen for), we need to help the teacher change how they feel about student responses–how their own emotions are regulated when they hear students respond and to even change how and when the brain’s reward center get activated.

In order for the emotional states to act as an appropriate guide, we need the teacher to experience pleasant emotional states when they do understand what the students are thinking, and we need the teacher to experience mild discomfort when they don’t understand what the students are thinking (either because they have too little information or they don’t yet understand the meaning of the  information they do have). Again, this description is not the totality of what changes will be needed to emotional regulation, but it’s a decent first step.

Community: How a Community Shapes What a Teacher Values

I find myself now trying to work with new teachers at all three levels. Over-rehearsing new talk moves so as to break reflexive habits, modeling and practicing attending to student thinking, and providing experiences where getting access to student thinking is tied to activation of pleasant emotional states. I think at first I focused on the second (attending to student thinking), but didn’t emphasize enough the moves that make it possible. Later I focused more on the talk moves, thinking that it would generate attention on the right kinds of things. That doesn’t quite work either. My later efforts at combining training in the use of talk moves with training in attending to and interpreting student thinking were more successful, but still inadequate. Without attention to emotional regulation and positive emotional experiences with both the process and outcome of teaching this way, students were very vulnerable to relapse into unproductive dialogue. Put into the actual classroom, they would revert largely because the underlying emotional states that drive the unproductive behavior were likely to be triggered when they take on full responsibility for teaching a class by themselves (without enough support).

To a large degree, change at all three levels is only likely to happen when new teachers are entering a community in which these three are actually happening; there are

  • different ways of talking to students that are made visible and explicit,
  • practices of attending to student that are visible and explicit, and
  • varied opportunities exist to experience positive feelings associated with these two

Associating positive feelings can be worked at from a variety of vantage points. New teachers need to spent time in fun, exciting, challenging classrooms where students ideas are shared and valued creates pleasant experiences. The process of being in those classrooms can be stimulating and fun in a way that promotes change to emotional conditioning.  That said, since early teachers’s current reward centers are still tied to “correctness”, new teachers need to see how the visibility of student thinking in the classroom actually helps with learning.

I should add  it can be somewhat counterproductive when emotional associations are too strongly tying rewards to solely the visibility of student thinking. A classroom where student thinking is visible is necessary for this kind of teaching and learning to occur, but it is not the end goal in itself. I have made the error myself and witnessed teaching errors where a teacher can be too emotionally attached to the visbility student ideas, and as a result, student thinking isn’t leveraged meaningfully to make progress in learning. Of course, we want to the visibility of student thinking to be rewarding, but it should also feel disconcerting if that visibility of student thinking isn’t then being used to enhance learning. While early teachers’ understanding of learning outcomes may solely be tied to correctness, we can work on expanding their notion of learning later. For that reason, I want my earliest apprenticing students to experience these kinds of classroom, where they can see both the beginning process and ending products.

There’s lots more to say, but I’m done writing for now…

What is sophisticated?

December 6, 2017

One of the changes our new curriculum requires of instructors is a shifted vision of what sophisticated problem-solving can look like.

I’m not sharing this particular photo of student work necessarily because it’s exemplary. Rather, it’s a good boundary case– I see evidence for sophisticated problem-solving and I also see what are often seen as traditional markers of immature problem solving.

I notice that students write the equation for gravitational potential energy as U = gmh. This is non-standard and so stands out to me. When they use this equation, they include units, and their final expression has units appropriate for energy.

I notice that the students do not write an explicit energy conservation equation. Rather they bracket the two gravitational potential energies and find the difference.

It suggests to me that they know that energy differences matter, and that perhaps they are thinking in terms of energy transformation (and perhaps less so explicitly as energy as a constant).

They set this energy difference equal to an expression for kinetic energy. They drop some units during the mathematical work, but include final correct units upon determining the speed.

They later use this speed in an equation to calculate the net force, this too includes units, some that look like they were squeezed in afterward.

This net force value makes its way to an arrow next to a free body diagram. The free body diagram is drawn, with Tension force drawn longer than weight. They then make use of known value for weight and net force to calculate the Tension.

As with energy having no explicit algebraic statement of conservation, the students write no explicit algebraic statement for Newton’s 2nd Law or for the sum of forces.

Traditional markers of sophisticated solutions value explicit algebraic statements of big ideas– energy conservation, Newton’s 2nd Law. We do not see that here. What is also valued at times is prowess at algebraic manipulation. Here we see calculations done piece meal.

Students use equations to calculate intermediate values. How many joules? How fast? What net force? None of these intermediate calculations are big ideas: “potential energy”, “kinetic energy”, and “centripetal force.”

Big ideas are instantiated arithmetically–considering a difference in potential energies to determine a quantity of kinetic energy. Arithmetic reasoning about relationship between individual forces and net force.

One of things I’ve come around to seeing in students’ work is this– I look for evidence that they are organizing their work around the big ideas.

The traditional view mostly looks for that evidence in the limited places, especially for the new learner, and thus often misses sophistication when it appears. And inadvertently, such limited looking can end up encouraging the opposite of one intends. Mindless equation use.

One of the ways to see students work here not as mindless equation Work is this. is the following. It is true that Students do not seem to use equations to express big ideas. Rather, I would suggest that students use equations as a means to get into the world of big ideas. As such, we see that they know how to reason about concepts like forces and energy, and are adept at enacting such reasoning when they have concrete values with which to reason. They sometimes use representations like the FBD to help organize how to do that arithmetic thinking. The equations are a tool that gets them a concrete handle in to the world thinking about forces and energy.

I can see this also in how they use or don’t use equations that are old and more familiar vs new and unfamiliar.

Students actually don’t even write an equation for relating mass and weight, like W = mg. Rather, they just write m = 200 g, and W = 2N. This unit prefix change and calculation is familiar to them , since they learned it months ago. I see their fluency with this and presumed fluency of others as making sense with them not showing this explicitly.

Students write the energy expression for potential energy in their own way, with the “g” as the leading variable. This equation helps remind them of what information is needed and how to put it together. Energy was learned weeks ago, and so has undergone some revisions. They use this equation fluidly with units as they calculate, even converting length prefixes from cm to m without much ado.

Circular motion, however, is our most recent topic and the equation for centripetal force that they write takes on the exact form it was presented to them. They plug numbers in first and go back and add the units later. This makes sense to me with their having less familiarity. It’s like right now This an equation that is strictly for a calculation process, one they have not yet internalized. Yet the result of that process (net force) they seem to what it tells them and how to proceed with that information.

Part of this could be that I’m not pressing students to work at a sufficient level of abstraction. It could be that I’m allowing them (too safely) to work concretely with these big ideas. As I see it, I’m getting them to actually learn the big ideas using skills with which they can actually be thinking about the big ideas. My students can do mathematical sense making, but it more likely to take place with concrete values. Often for new learners, the push for algebraic abstraction suppresses thinking about the big ideas. And so I’m somewhat happy with the balance, but I know that it is also true that I should be looking for fruitful ways to stretch that understanding into uncomfortable territory. We do explore that boundary some, but probably not enough for certain populations of student who need that.

Anyway, those are my thoughts for the evening.

Circuit Representations

December 3, 2017

I shared this on twitter and there was enough interest that I figured I should archive on the blog.

We’ve been playing around with circuit representations this semester… the first two were really helpful for students in clarifying and connecting certain concepts.

The third was done later to orient drops in potentials as vertical descents. It’s making me think about how I can more explicitly link potential in circuits with gravitational potential contour lines.

Momentum Stacked Graphs

November 21, 2017

For 1D impulse and momentum, we need a more integrated representational set than what Knight’s textbook gives us. They do before and after (sort of vector) diagrams and force vs time graphs for “during”.

I’m not quite ready to stray really far from what Knight supports (since I like the class to be coherent across class and text); so, although I like IF momentum charts (from modeling), I’m thinking more of cycling back to velocity vs. time graphs more strongly  and adding momentum vs. time graphs.

Something like this:

momentum_stacked_graphs

Draft of Projectile Card Sort Task

November 21, 2017

Putting together a draft for a matching task related to projectile motion. Yah!

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Revised Prompts :

Round 1: Hand out just the motion diagram, description, and list of initial values. Have students sort the cards into matches

Round 2: Add the graphs to the mix, and have students complete the matches.

Round 3: Ask students to use the graphs to determine the time of flight and horizontal distance traveled. Compare and contrast the three cases. Which one spent the most time, least time? Why? Which on traveled the most distance? Why?

Round 4:  Add equations into the mix, and have students complete the matches.

Round 5:  Ask students how they can find time of flight and horizontal distance from the equations (rather than graph). Explain what is similar / different about using graphs vs. equations.

Round 6: Take away the graphs (or flip them over), and ask students to see if they can determine the time to maximum height and the value of maximum height from the equations.  Check answers against graphs. If they get stuck, have them go back to graphs. Compare and contrast cases: Which one go the highest? Why?

Round 7: With graphs back in mix, ask to find the speed of the ball at it’s highest point. Compare and contrast. Which was moving fastest at its highest point? Why? Which one slowest why?

Round 8:  Ask students to find the final speed (just before hitting ground). Compare and contrast? How did the final speeds compare? Why?