Reading: “The benefits of completing homework for students with different aptitudes in an introductory electricity and magnetism course”


F. J. Kontur, K. de La Harpe, and N . B. Terry

I am trying currently trying to write my student materials for next year for my L2 Physics course. I want to base the mechanics unit on modeling instruction again, however I am trying to trim down from 2.5 terms of modeling to 2 terms (20 weeks). And although it seems like not much to trim down, every single lesson that I am getting rid of is painful.

I am trying to strike a balance between mastery of physics (with extended time spent of mechanics through a modeling instruction method), and some breadth to the course. I think with the extra 5-6 weeks we will do the optics unit. However I still want to have the conversation of “depth vs breadth” with the other teachers from around NZ and the powers who do control it all…

Back to homework. I am wondering do I write homework sets into my materials. As I wrote them I reflected on this year, and I realised only my top kids really completed any homework this year. Should I write it for next year? Should I enforce it?

A bit of reading led me to this article by F. J. Kontur, K. de La Harpe, and N . B. Terry (“The benefits of completing homework for students with different aptitudes in an introductory electricity and magnetism course”). They looked at not how a class may improve from homework, but instead how different aptitude students benefit from homework. They found “On average, successfully completing many homework problems correlated to better exam scores only for students with high physics aptitude. On the other hand, all other students showed zero or even a negative correlation between successful homework completion and exam performance. Low- and medium aptitude students who did more homework did no better and sometimes scored lower on exams than their low- and medium-aptitude peers who did less homework.” AHHH! What?! “Sometimes scored lower” …

it is worth noting that we as instructors assign homework to our students because we believe that all students will receive a learning benefit from doing homework. This belief is predicated on the idea that there is a strong positive correlation between making an honest effort to do well-chosen homework problems and student learning, qualities we attempt to measure using homework scores and exam scores. If there is no correlation between successful homework completion and exam scores, we should carefully rethink these assumptions, especially considering that assigning, completing, and grading homework is often a very time-intensive activity for both students and teachers.

Its worth noting that this article looked at the effect of both online homework, AND written homework. Online homework had negative correlations between completion rates and exam scores for medium and low aptitude students, and written homework had no correlation for these same students.

Not about homework, but I like this quote all the same: “As Redish et al. say, “We are frustrated by the tendency many students have to … spend a large amount of time memorizing long lists of uninterpreted facts or performing algorithmic solutions to large numbers of problems without giving any thought or trying to make sense of them

Kelly O’Shea writes a good physics teaching blog I follow and she has posted on similar thoughts here.

So it looks like, for this course at least, homework will stay out of the course. Certainly something that needs to be further investigated… One possible avenue is “interleaving”. This means that homework doesnt just focus on one topic, but mixes up  a number of different units. The research done on it (in maths) seems promising.


Experienced vs Expert Teachers Part 2

What would it look like?

My partner is a physiotherapist (in the hospital setting), and they have two pay scales. The first has 5 or 6 steps. The second requires alot of work just to get on, and it requires constant development to stay on and move up. I envision a similar “dual pay scale” in teaching as well. Experienced, and then expert.

The first argument I can see against this is that “all teachers must be experts (professionals), so really we should just have the 2nd pay scale. But that’s what we already have!”. I agree in principle, but the reality looks much different.

Our current pay scale has 7 or 8 steps, and although there is an appraisal system that you are required to be a part of to move up the pay scale,  you basically get promoted up them if you have a pulse. I previously did not agree with this pay system. It wasn’t until I started to take student teachers in my class that I was reminded of all the things I do in a classroom that I take for granted. How I set up my board, how I manage the class, my understanding of the curriculum, timing etc. All this has come through experience, and so now I am in a place where I will gladly say that my experience is an investment, and worth something. Therefore I am happy that I get paid more than graduate teachers. And this really sums up this pay scale. It is an experience pay scale.

The expert teacher has more than just experience, they have the answers to “why does this work in my classroom”. Not all experienced teachers are expert teachers, and not all experienced teachers can, or want to, become expert teachers. Becoming an expert teacher requires a true passion for the profession. It requires time, introspection, evaluation, research, and a heap of learning. I think an expert teacher can accurately answer Hattie’s mantra of “know thy impact”.

The second argument against this “dual pay scale” is that “to become an expert teacher, dont you need to go through an inquiry/appraisal system each year in order to improve your self? Everyone already does that, so everyone is an expert teacher!”

Becoming an expert teacher really does sounds like the inquiry/appraisal system doesn’t it? The problem with our current appraisal system is that everyone is forced into this system, and so the status quo has an incredibly low bar. Although we like to look at our own profession with rose tinted glasses, if we held our appraisal up to scrutiny against the scientific method (which it really should be), we would be laughed off the stage. The reality of our current system is that appraisal and inquiry (in secondary teaching) are largely a box ticking exercise, and consist of “I tried this new thing”, and “it worked”. I may sound cynical, but this is based on experience of both what I do for my inquiry, and what I witness others do.

I would like to see two pay scales (experienced and expert). The first pay scale rewards the journey towards experience. The second pay scale is tied to new learning and the journey to becoming an expert teacher. I believe by having a much higher bar on who can enter the expert pay scale, then we could be far stricter and have higher quality teacher inquiries. Maybe if there were 5 steps on the “expert scale”, then the inquiries could be some self chosen, and others that were predetermined? As an example there could be five years, and these inquiries are 1. Collecting evidence. 2. Self choose. 3. Subject specific pedagogy. 4. Classroom Management. 5. Self choose.

Ill repeat my conclusion from my last post: I seriously believe that teaching wont be recognised as a “true profession” if we continue to spout the mantra that “every teacher is equal”, and “every teacher is an expert”, when in fact both of these mantras are very far from the truth. As Hattie continues to say “too much discussion is focused on between-school differences when the greatest issue is the differences within schools”. That is, the differences between teachers.

Experienced vs Expert Teachers

I recently watched a paper being debated at the 2018 PPTA conference. This paper was entitled “Career Pathways – Subject Pedagogy Specialists” . During the debate one teacher spoke to how he already “is a subject expert”. Maybe he is, maybe he isn’t. But he certainly thinks he is. I have my doubts though.

I think the difference in one person’s confidence, and my doubts is what I am calling the difference between experienced teachers and expert teachers.

An experienced teacher could be a great teacher (or not…), they know their curriculum and they are effective communicators in class. They manage behaviour well in their classes, students enjoy their classes and they come out of their classes as stronger learners than when they entered.

An expert teacher on the other hand knows why they are a great teacher. They know what pedagogy works specifically for their subject area. They also know other types of subject specific pedagogy and they could compare and contrast the different methods. They know a variety of classroom management techniques and know which are effective for a certain type of teacher and a certain type of classroom. They understand evidence in their classroom, and also they understand evidence more broadly in education research. Expert teachers are very aware of their own weak areas and a working towards improving them.

For me the difference between a experienced and expert teacher is the difference between a great rugby player and a great rugby coach.

I do not profess to be an expert teacher. In fact, I think I am still searching for one to help me. And that is the real reason I want to push in form these two pay scales. One reason is one day I aspire to be there, but for now I just want to meet one, and learn from them.

I seriously believe that teaching wont be recognised as a “true profession” if we continue to spout the mantra that “every teacher is equal”, and “every teacher is an expert”, when in fact both of these mantras are very far from the truth. As Hattie continues to say “too much discussion is focused on between-school differences when the greatest issue is the differences within schools”. That is, the differences between teachers.

I think, until we have teachers that can explain what they are doing, and why they are doing it (subject specific pedagogy, and classroom management etc), then we will continue to not be seen as a true profession, unlike medicine or engineering.

Quote of the Day: 30-8-2018

“When asked to draw a force diagram for some simple situation, most students emerging from any level of introductory physics course are likely to draw objects which look like a porcupine shot by an Indian hunting party – the number and direction of pointed entities being essentially stochastic.” ~ Arnold Arons (from R. Knight – “Five Easy Lessons”)

Reading: Depth Versus Breadth: How Content Coverage in High School Science Courses Relates to Later Success in College Science Coursework


Schwartz, Sadler, Sonnert, Tai

Depth or Breadth in high school science? The answer is a resounding “depth”. This is a study involving 7000 university students.

“…indicates that those students reporting high school science experiences associated with the group “depth present–breadth absent” have an advantage equal to two thirds of a year of instruction over their peers who had the opposite high school experience (“Depth Absent–Breadth Present”)”

“These appear to be that students whose teachers choose broad coverage of content, on the average, experience no benefit. In the extended model, we arrive at these results while accounting for important differences in students’ backgrounds and academic performance, which attests to the robustness of these findings. The findings run counter to philosophical positions that favor breadth or those that advocate a balance between depth and breadth”

“Students who experience breadth of coverage in high school biology perform in college biology as if they had experienced half a year less preparation than students without breadth of coverage, whereas those who are exposed to in-depth coverage perform as if they had had half a year more preparation than the students without depth of coverage. In chemistry, depth appears to be equivalent to one quarter of a year more of high school preparation. In physics, the effect is closer to two thirds of a year more preparation” 

The Finnish model

From a teacher colleague of mine today: He wishes were operated in a Finnish model. In this model they are very “initial loaded” with teacher expectations. That is, their are strict entrance requirements on teachers into teacher education. It is a rigorous initial education scheme (masters I think?) and then once qualified teachers are trusted to be professional. In NZ this is almost reversed. Teacher training is not limited entry, training is not as rigorous (6 weeks in some cases – Teach First NZ), but once qualified, teachers spend a lot of their time jumping through hopes with NZQA (moderation), and the education council (for their inquiry).

I would love to see someone do some sort of cost-to-benefit analysis of the teacher inquiry in NZ with a typical secondary teacher. By cost I mainly mean time, and benefit is of course to the teaching profession.

I know I sound very cynical with this post, but after a very long day with a few unsuccessful lessons, and a whole heap of administrative hoop-jumping, I feel Ive earned it…

Reading: Big Ideas in Science Education


Reminds me very much of the 7 cross cutting concepts of the NGSS in the US. These a little bit more specific, but I like the general idea of saying – “what is really important?”

  1. All matter of the universe is made of small particles
  2. Objects can affect other objects at a distance
  3. Changing the movement of an object requires a net force on it
  4. Total Energy is unchanged but can change from one form to another
  5. The composition and process of the earth affect its surface and climate
  6. Our solar system is a small part of the universe
  7. Organisms are cell based, and have a finite lifetime
  8. Organisms will compete for food, energy and resources
  9. Genetic info is passed down from one generation to another
  10. The diversity of organisms is a result of evolution

There are also 4 ideas about science

  1. Science is about finding causes of/in natural phenomena
  2. Scientific explanations, theories and models are those that best fit the evidence available at a particular time
  3. The knowledge produced by science is used in engineering and technologies to create products to serve human ends
  4. Applications of science often have ethical, social, economic and political implications

This list kind of answers the question – what is important for our kids to learn in science after they leave school.

There are a number of good readings at the bottom of the site too.