About physics and teaching

Archive for March 2011

Leading with mistakes

with 7 comments

There has been some internet-based discussion recently amongst math and science teachers about the usefulness of Khan Academy videos in particular, and lecture videos in general. Derek Muller at has created a short video about his research findings into the efficacy of using videos to teach introductory physics concepts. If you watch that quick video, you’ll get a snapshot of one thread of the recent discussion. The upshot of Derek’s argument is that videos which contain student misconceptions and show real people working with and through their misconceptions lead to more successful learning by the observer of the video than does a straightforward exposition of the proper concept.

A recent blog post by John Burk at quantumprogress discusses the idea of using video examples of problem solutions that include common student mistakes and/or misconceptions. The idea is for the students to identify the mistakes made, thereby potentially learning more than if they simply ceded control to the expert on the screen solving the problem. We’ve all seen the effect of students watching an expert solve a problem for them. The students watch the solution unfold before them, usually failing to notice the subtle (albeit clearly presented) steps that cite fundamental principles and call out the broad models or chunks of knowledge that lead the expert to appropriately set up the problem (they just see the problem set itself up). Then they are bewildered at the prospect of starting a problem themselves.

In the comments to John’s blog post, there are some fantastic observations. One is from Jim Doherty who mentions the possibility of giving a correct and incorrect solution to the problem, having the students select the correct one and explain the mistake in the incorrect one. He also mentions a device used by a colleague, whereby a troubled student (“Careless Carl”) appears in problems, making common mistakes. Joss Ives wonders in the comments whether such devices might lead to student frustration on a level that leads them to give up. I’d like to address 1) how I use Careless Carl and 2) how I avoid the “oh crap, I just agreed with this idiot, which means I’m an idiot, too, so I quit” syndrome.

Careless Carl makes appearances in my class all the time, as John Burk knows. He went by the name Bobo (what a clown) when John and I taught together, but now Kelly O’Shea has given him the name Throckmorton (apologies to the Throckmortons of Fort Worth/Dallas, Texas). Throcky (who is your cousin) is a bit more advanced than Bobo… what he says is often ALMOST correct, containing lots of good reasoning with some crucial boneheaded blunder buried deep inside. Sometimes students reluctantly agree with Throcky, dropping their head, wincing, knowing that they are in less than stellar company. But they generally don’t “throw their hands up in the air in defeat,” as Joss worries.

Here’s why: My students have a very strong conception of their scientific self as something that is fluid and ever-changing. They have this conception because we talk about it! Not for long periods of time, but it comes up at least once a week. They have heard again and again that what they know to be true about the world now will, undoubtedly, change as they become wiser, more skilled, more observant and more careful. In this way, they are just like established, expert, working scientists. Scientists expect their view of the world to change and evolve as they understand more about it.

Many of my students, when faced with their own mistake, will say something like “Ok, that was my eighth grade science self. Let’s see what’s wrong.” In fact, “eighth grade self” has become a very popular phrase this year (although last year my students preferred to blame Aristotle, rightly or wrongly, for everything). This just happened yesterday, in the same way, in both of my Honors classes. We are about three days into studying the central force particle model (uniform circular motion). In each class, someone spoke up asking “Wait… if the speed is constant, how is there a net force on the object?” I asked what principle or model the student was applying and in both cases the answer was something like “My gut.” They know by now that their gut is not any better at physics than Throcky. The class then puzzled out the answer. About half knew right away what the mistake was, but, because they are extraordinarily kind and gentle, didn’t say anything until the answer emerged naturally from those having what they called an “eighth grade moment.” It was beautiful, mainly because the students expect this to happen.

I’m not saying none of my students get frustrated. I had a minor meltdown (including tears) to deal with after dinner two nights ago. But the student was much better when he realized that, even though he hadn’t truly learned how to use vectors to do momentum problems yet (even after three months), he had learned something very valuable about what kind of practice doesn’t work. And his assumption is that tomorrow he will understand more about momentum and vectors than he does today.

If there is one thing middle school teachers could instill in students that would help them the most in high school, it is the idea that their own conceptions of the world are bound to change. They should seek out the opportunities to change these conceptions and celebrate the replacement of old concepts with new. I have seen this trait in some students (locally, the Newark Center for Creative Learning teaches this habit fantastically), so I know it is possible to do. This makes students much happier and eager learners.

Written by Mark Hammond

2011/03/26 at 09:50

Posted in deep practice, mindset

Deliberate Practice in Physics

with 4 comments

I have been trying to figure out the ways my colleague, Kelly, and I get our students to engage in deep practice (Daniel Coyle’s term) or deliberate practice (Geoff Colvin’s term) in the classroom and on their own when studying physics. This article by Stephen Chew nicely outlines the problems incoming college students have with mindset and study skills, arguing that they often lack the knowledge of what serious study looks like or feels like. While the work I’m trying to do with my students should definitely prepare them for studying in college, my more proximal concern is getting them to learn physics. I’m admittedly making an assumption that getting them to study in a more serious, deep and productive way in order to learn physics should serve them well in college, too.

Colvin’s book (Talent is Overrated) outlines some of the hallmarks of deep practice.

It is an activity designed specifically to improve performance, often with a teacher’s help; it can be repeated a lot; feedback on results is continuously available; it’s highly demanding mentally, whether the activity is purely intellectual, such as chess or business-related activities, or heavily physical, such as sports; and it isn’t much fun.

So what is it we actually do, as teachers, to improve performance?

Kelly and I do a lot of small group problem-solving sessions using whiteboards. Essentially the students do in the classroom what they used to do for homework. The reason I want them to use class time as practice time is that I can see exactly what is going on. In-class problem-solving also allows “continuously available feedback.” I started using class time as practice time after taking a course in Modeling Instruction, but my misgivings about homework started much earlier after deliberately watching students do homework (I work at a boarding school, so I am privileged to be able to witness this… in exchange for working a 15 hour day).

We have students present their work verbally. Talking one’s way through a thought process is fantastic practice. I need my students to do even more of this.

We let students, after plenty of scaffolding early in the year, design their experiments in the laboratory. Early in the year we give them a structure for designing an experiment (roughly: make and record initial observations, use that list of observations to decide what you can measure and how to measure it, pare that list down to what might be related and/or interesting to the phenomenon at hand, then decide what variables to hold constant, which to vary, and what you are going to plot), and we step through this structure, little by little handing off elements to the kids until they can design their own experiment with only a bit of coaching.

But what do we have students do that is “specifically designed to improve performance” when they aren’t with us. I don’t want to create students who depend on me being present in order to do physics. This makes me worried. How do I come up with something new, and does it really work? What evidence do I have? Is it working, but not yet? Does it seem to work, but then not lead to deep understanding that sticks? These are questions that bother me, leading me to stall while planning classes, my perfectionism becoming my procrastination tool of choice again, just like in college. Ok, I’m better than I was in college, but still… I don’t have good answers to these questions.

One hallmark of repetitious skills building is that the performance being worked on is altered in some way, and this is a possible solution to the problem of deliberate, solitary study. Problems are given with partial information, wind sprints are run uphill (even though the lacrosse field is flat), swimmers sprint tethered either to impeded them (the power rack) or to assist them (speed assist training), students create problems rather than just solve problems given them. The trouble is, I feel I can come up with many more ways we focus on performance in swimming (next post, I swear) than we do in the physics classroom. Maybe it isn’t true, but it’s a nagging concern. I’d love ideas about how others see themselves helping students toward deliberate practice.

Written by Mark Hammond

2011/03/19 at 10:03

Posted in deep practice, mindset

Why do we think sports are important?

with one comment

At my school, all students are required to be in an afternoon activity every afternoon for the entire year. Most afternoon activities are sports-related: either participating on a team, helping manage a team, or doing an independent sports workout (crew winter workout, training for a marathon, etc. usually reserved for upperclassmen). Theatre, organic gardening, mock trial, and non-athletic individual projects (usually only seniors) are other options. So why do we demand that most students spend 1.5 to 2 hours each and every day on a sport?

Typical answers include: teaching teamwork, teaching students to be part of something bigger than themselves, teaching character, teaching lifelong fitness skills… you probably know a couple more reasons. All of these are good reasons, and I won’t knock them. Sports are also fun!

But I think that the most important lesson I learned from swimming as a youngster was that I could become good… actually pretty darn good… at something if I really worked hard at it.

How I learned that hard work makes a difference

I was not a “naturally talented swimmer.” As a pre-teen, I was roughly spherical (perhaps foreshadowing my own predilection for creating simplified physical models). I also had terrible eyesight. My myopia was severe and ever-changing. Within a month of getting new glasses, baseballs again appeared as fuzzy white things with totally unpredictable paths. During neighborhood football games (“hey! I can see THAT ball!”), I always heard “Hammond, you hike the ball and go long.” I went long… totally, but futilely, open in the endzone… beyond the endzone, risking my life by crossing the drive into LeBaron Caruther’s front yard (not that LeBaron was a bully… he wasn’t… but Google him and see what he was really good at, and then realize that in high school he used his parent’s front yard for LOTS of deliberate practice).

In the pool, my poor eyesight didn’t bother me. I was also rather floaty at that age (being roughly spherical and all). Yet I was slow. Very slow.  There were two boys I swam with who looked, at age 10, like miniature men… washboard abs, bulging arms and thighs… and they were both ranked in the top ten nationally in our age group. They were so-called natural swimmers. Everyone agreed that they had talent. Me, not so much. But I was a good egg, a hard worker, and several wonderful coaches encouraged me anyway. Within a year, in summer league competition, I could beat those neighborhood kids who wouldn’t throw the football my way. Within two years, I was working out with my naturally talented, svelte and muscled acquaintances, and giving them some tough workout competition. In fact, I was a maniac during workouts. I remember Bobbie L., a year my senior and a state record holder, looking back at me in puzzlement asking “how the ___ are you keeping up with me?” Still, in competition, these boys could easily defeat me. It was only after four years that I could compete reasonably with them at championship meets. The vibe was ever positive and I thrived.

What I learned from swimming

My swimming experience had given me a valuable advantage: I was in possession of a growth mindset… at least some of the time. Unfortunately this mindset did not extend to academics until I was in college (frankly it didn’t occur to me until that point that I could transfer my knowledge from the pool to the desk… just ask my high school Latin teacher). As my swimming buddies and I became high schoolers, I started to surpass them… not always, but often enough. They were no longer nationally ranked. They were, as I knew from daily contact in the pool, not working as hard as I was. And their talent, whatever that was, was not enough to see them through to a NCAA Division I experience. I suspect that they felt their talent had been exhausted at some point around 14 years old. They weren’t as good as they had been told. If you’ve reached your potential, why kill yourself trying to improve any further?

Pretty soon in college, I decided the time I was putting into swimming was probably better spent elsewhere (and eventually I settled on intellectual pursuits after a short detour, but we’ll just pretend that didn’t happen). I still swam, but not passionately, and not with the same commitment as before, partly due to a series of injuries, but mostly due to burgeoning intellectual curiosity. But the lessons learned from swimming… that hard work pays off, that you don’t have to be good at something right away, that improvement feels good… stuck with me. These are the lessons that I seek to convey to the athletes with whose education I am charged. The fact that many of our students play three different sports, often being fairly good already at one or two and stinking it up in the other, gives them ample opportunity to see growth and change in their performances.

Nevertheless, I find it strange that it didn’t occur to me that, although my friends’ talent didn’t carry the day, perhaps the whole idea of talent was flawed.

Later on, I’ll write about what I learned about deep practice (deliberate practice) from swimming. Interestingly, my own swimming career involved very little deep practice, but I saw it, it puzzled me and only years later did I figure out what I had been looking at. Later, though.

Written by Mark Hammond

2011/03/16 at 21:05

“Naturally Gifted”

with 6 comments

I was visiting Carnegie Mellon University yesterday with my son, a high school junior. I grabbed a piece of paper titled “Science” from the wall of information in the Admissions Office as he signed in. On the back, there was a series of questions followed by answers. One question was “Can I create a degree that combines science and the fine arts?” This was followed by an answer beginning, “Carnegie Mellon recognizes that there are students who are naturally gifted in both fine arts and the sciences.” My current understanding is that studies designed to find evidence of “natural giftedness” have come up empty-handed.

Absolutely nothing else on that double-sided information sheet indicated that the view that some are just “gifted” is widely accepted at Carnegie Mellon. In fact, the words and phrases “work,” “doing what it takes,” and “providing you with the skills, knowledge and training” occur. Perhaps it is only biologists that paint or physicists who play the violin who are considered by Carnegie Mellon to be “naturally gifted,” but I think instead that a typical mistake was being made. Even people who are trying very hard to readjust their mindset to de-emphasize the assumption of the primacy of innate “talent” make occasional references to innate talent. I have been talking to colleagues about the lack of evidence for inborn talent recently. I have read Carol Dweck’s “Mindset” and am working on “Talent is Overrated” by Geoff Colvin. The messages of these very different books resonates with something I think I learned in the swimming pool as a youth. I’ll write about that later, but what I want to say here is that even my colleagues who believe that hard work is the most important determinant to success still sometimes slip up and use the language of innate, inborn talent (I include myself in that group as well!). The assumption that certain skill sets are hardwired into us at birth is so prevalent in our culture that it is very hard to keep it from popping into your conversations.

This is not a matter of policing our speech for political correctness. It is not that I want to avoid writing student comments that praise a student as “bright,” “talented,” or “smart” for fear of offending the student not labelled so. No, it is nothing like that. Instead, I fear for the student so labelled. First because it ignores the hard work the student has done previously, and, second, it sets them up for failure as soon as they hit a concept with which they must struggle for awhile.  The assumption of innate talent also denies the possibility that other students starting out behind the frontrunners can catch up. Finally, such language simply doesn’t appear to be supported by evidence.

Even students who have worked hard sometimes still attribute their success to innate talent. I have one student, who told me she was “just good at Spanish.” Upon questioning her about her background in Spanish, she told me that she had a very rigorous middle school Spanish class. She had worked “very hard.” In fact, she said she worked harder on Spanish than “any other subject in middle school.” Then she noted that only now, a year and a half after arriving at high school, was she finally learning anything new in Spanish. Then I asked her whether it was any surprise, after she had worked very hard for three years and then had spent the last year and a half in relaxed review of Spanish, that she only now felt like her peers were catching up to her in Spanish? She gave me a very far-away look and a long “huuuhh.” This girl had essentially ignored her own hard work (and the pleasant circumstance of having a year and a half review), because society has told her repeatedly that stuff like this just happens… at some point you just find out what you’re good at. The fact that in seventh and eighth grade she was labelled “gifted” in Spanish may, in fact, have led her to deny the reality or the importance of her own hard work.

Written by Mark Hammond

2011/03/15 at 18:59

What Salman Khan might be getting right

with 9 comments

Salman Khan created Khan Academy, a website where you can get short video lectures about math (and many other subjects now). He is being credited with “revolutionizing education,” a description with which some critics take issue. Rather, these critics say (if I may boldly paraphrase), these videos are just standard lectures packaged a different way, and therefore still suffer from the same problems of transmission that live lectures suffer.

Sal Khan has given a TED talk video entitled “Let’s use video to reinvent education” which is worth a listen. Yes, there has been hype about Khan Academy… the “reinvention of education” being credited to any one website or just to the “use of video” is a little much… but I think there are two lessons here that are worth considering.

First, there is “flipping the classroom,” with lectures being homework and practice problem-solving becoming classwork. Second, there is the idea of making sure you master each skill before moving on.

Flipping the Classroom

I was interested in seeing Khan’s video lectures when I first heard about them last summer because I have nieces and nephews who occasionally ask me for long distance tutoring (usually just short term “I can’t get this one thing” kind of help). I thought perhaps these videos could serve as a first line of help, as in “Watch so-and-so video, then let’s talk.” I was not overwhelmed by the videos, specifically because they seemed a pretty direct translation of whiteboard, classroom lecture to a computer screen. Also, the presentation was a bit messy, with what looks like a mouse being used to “write” … but maybe that’s just me being picky. And anyway, there’s just no reasonable way to make the video lecture interactive other than the fact students can rewind and pause, skip over parts that seem too obvious, etc. (which definitely makes video lectures better than traditional lecture, especially for the easily distracted like me).

I had also been experimenting with videoing short lectures for my own physics classes, with the hope of freeing up valuable classroom time with the students. I believe in making class time practice time (I think I’m stealing this phrase from Grant Wiggins, but I’m not sure). I do short mini-lectures occasionally, so I reasoned that if the kids could watch these lectures at night, we could get right down to practicing with new concepts, practicing new skills, and talking more about what we were doing. Currently this effort is not going so well in my own classroom, mainly because I haven’t created many lectures and the whole idea is still a novelty to my students. The result is many students figure they don’t have any “real” homework when a video lecture is assigned. It is short, it is a video, there’s nothing to turn in or show me the next day, so it falls to the bottom of their priority list.

Nonetheless, I still think that having students puzzle over lectures at night and do problems with each other (and with me) during the day is vastly preferable to the standard classroom. So I’m going to keep experimenting in the direction, and I hope to write about this topic in detail in the future.

Finally, if I can find someone who presents a topic more engagingly or more clearly than I do, I’d rather have my students watch that lecture over my lecture. I’ll add value the next day when the rubber meets the road in my classroom.

Mastery-based Progression

The other good idea in Khan’s video is that a student should master each concept or skill rather than moving on with incomplete or faulty knowledge. I have been using Standards Based Grading this year for the first time in an effort to track student mastery of learning objectives in a more rigorous and transparent (to the student and to me) way. The point that Mr. Khan makes when he asks what the student who made a 95 on a test missed, and whether that small misunderstanding or gap will hurt the student in the future is an excellent one. Using traditional grading techniques, the student with the 95 feels that he’s finished, rather than feeling like he still has 5% more to learn before he can say “I’m done.” The entire idea that you get one chance to learn a skill or concept before moving on is just totally odd to me. I have in fact heard teachers say “The students just get one chance in my class,” and I shudder thinking of all the holes I’ll have to fill next year with those students. The reason for “moving on” is often the quest for more coverage, but there is also a strand of thinking that those who get the concepts and skills quickly are just more talented and should be sorted for college admissions.

In the near future I hope to write more on Standards Based Grading, sorting students by grading (and grading philosophies in general) as well as the idea of innate talent.

Written by Mark Hammond

2011/03/12 at 14:53

Posted in grades, SBG, talent