Introduction

What does a teacher really contribute to learning? ➤


Is it not the student's responsibility to inspire and motivate himself? The teacher leads by example, establishes trust (partly by easing the fear of failure), presents to students interesting or desired topics or skills, and provides instruction and assessment (that hopefully doesn't punish). The rest is up to the student. Or is it? Is successful teaching only measurable by the extent to which a student is somehow induced to learn?

What teachers often share with each other is the craft of teaching; the employment of techniques and the solution to problems. Teachers rarely discuss what teaching itself actually is. It is like asking a fish what swimming is: "I don't know, I just do it."

There is such a thing as teaching. ➤


Teaching is not coaching, though it can include coaching. Teaching is not training, though training can be a part of teaching. Teaching is not just explaining, not just instructing, it is not supervising, it is not facilitating, not babysitting, not managing, not providing services, not delivering curriculum, not simply and somehow the inverse of learning. It is its own activity, its own expertise, an expertise that happens to have student learning as an end goal.

Why define teaching? ➤


If teachers don't define teaching for themselves, others will, and quite likely to the detriment of teachers. The problem is that the "wrong" definition of teaching can harm and interfere with a teacher's ability to really teach. What is a "wrong" description of teaching? Here are just a few examples: babysitting, coaching, facilitating, managing, providing services, delivering curriculum, the inverse of learning. Why are these descriptions wrong? Because the focus is either on behavior control or delivery of instruction, but not at all on what can be described as engagement.

There are two problems. Delivery of instruction includes designing instructional materials and designing tests. Both of these activities can be done on a corporate or academic level by experts, with an eye toward monopolizing, automating, and monetizing such activity. Teachers are just expected to deliver the canned curriculum to students. And much of what could be thought of as engagement is instead thought of as classroom management, often resulting in, at worst, moralistic or belittling approaches to control and discipline. Behavior modification approaches are an improvement, but best would be a sociological approach to adjusting student behavior, directly and indirectly, in the service of engagement.

Teachers need to engage to be effective. The key to this is understanding how a teacher's stagecraft and presence can help students interact with instructional materials. While discipline first, instruction second is a common recipe, it results unfortunately in poor outcomes. Instructional materials cannot teach themselves. Without an engaging teacher, any student is simply self-taught, for better or worse.


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David Labaree - Targeting Teachers

David Labaree is a historian and retired Professor of Education at the Stanford Graduate School of Education. This essay is taken from his website (https://davidlabaree.com/).

He introduces the essay thus: ➤

In this piece, I explore a major problem I have with recent educational policy discourse — the way we have turned teachers from the heroes of the public school story to its villains. If students are failing, we now hear, it is the fault of teachers. This targeting of teachers employs a new form of educational firepower, value-added measures. I show how this measure misses the mark by profoundly misunderstanding the nature of teaching as a professional practice, which has the following core characteristics:

  • Teaching is hard
    • Teachers depend on their students for their professional success
    • Students are conscripts in the classroom
    • Teachers need to develop a complex teacher persona in order to manage their relationship with students
    • Teachers need to carry out their practice under conditions of high uncertainty
  • Teaching looks easy
    • It looks like an extension of child raising
    • It is widely familiar to anyone who has been a student
    • The knowledge and skills that teachers teach are ones that most competent adults have
    • Unlike any other professionals, teachers give away their expertise instead of renting it to the client, so success means your students no longer need you
  • Teachers are an easy target
    • Teachers are too visible to be inscrutable and too numerous to be elite
    • They don’t have the distance, obscurity, and selectivity of the high professions — so no one is willing to bow to their authority or yield to their expertise

Here's the link to the complete essay on his website: https://davidlabaree.com/2024/07/04/targeting-teachers-3/

Here's the link to the original publication in Dissent, 2011: https://drive.google.com/open?id=1RvOPUrxd9UKMJGDPLB7UY5ZFlzrUmsHf

Posts

Notes on Radioactivity & Particle Physics


BP Tech Applied & Advanced Physics


Some notes on how we could approach teaching radioactivity/nuclear structure.

Background


The State of Massachusetts has revised its high-school science curriculum finally. But there is an orphan unit: radioactivity. I think this must be a new unit in the science curriculum, and the State first tried to add it to the Chemistry curriculum. Then to Earth Science. And finally to Physics. Where it truly is simply added, like a wart, to the front of the Physics curriculum. No attempt is made to connect it to anything else in the curriculum.

Now of course radioactivity is a proper physics topic, and the study of radioactivity led to important developments in modern physics. At BP Tech, where I teach, I always took a bit of the school year to look at basic atomic structure, knowing that students would see it again in chemistry. The problem with just tacking on radioactivity is that explaining radioactivity (as opposed to just describing it) draws you into quantum and particle physics, which could easily eat up an entire semester, or more. I spent a whole year thinking about how to present the topic without getting completely derailed from the rest of the physics curriculum. These notes explain what I came up with, on behalf of the entire physics teaching team at my school.

P.S. If you click on a diagram, you will see the original diagram (higher resolution) and you can download it.

Part I


Here is how I’ve tried to approach atomic structure in the past. After exploring the gravitational field and early into electrostatics (after introducing electric fields and electrons), I take a moment to look at a simple atomic model:



This model explains several things: the electric neutrality of atoms, the mobility of electrons, where our mass comes from. Later, when talking about electric current, I begin the discussion of how materials are constructed of atoms (or more usually molecules), and how electrons can basically hop from atom to atom. There is a net flow of electrons throughout a circuit but no single electron moves through the entire circuit (hence my distaste for the water model of electric circuits). I also take this moment to show various simulations that try to represent electrons moving through a circuit, and how they are incorrect and misleading.

Now it might be useful to discuss the residual charge (or residual electric field) of the electrons. Residual charge explains stickiness and friction and why chemical reactions happen and the unusual properties of water. Then when we get to the strong force, the idea of residual force will come into play, and the students will have already experienced the concept.

So this is as far as I have carried this in the past. We need to dig deeper in order to explain radioactivity.

Part 2


The nucleus, made up of protons and neutrons. What holds it together?


Wouldn’t the protons repel? Yes, of course, and it does happen in nature. Some atoms spit out a proton or neutron now and again. There’s your first taste of radioactivity. So there must be another force that’s really strong but has a tiny range. Call it a nuclear force, because it only operates in the nucleus, and more specifically call it the strong force.

Two issues: why the tiny range? And why does it apply to neutrons as well as protons? Let’s assume that protons and neutrons are made of something similar, and let’s call these constituent particles quarks. It turns out that protons and neutrons are made of 3 quarks each. And protons and neutrons differ by only one quark. The strong force is what holds the quarks together. Here’s a model of a proton:


The strong force that exists outside the “boundary” of the proton (or the neutron) is the residual strong force. This is what holds protons and neutrons together.

At this point, I think there is no sense in complicating this picture. You could point out that there are different kinds of quarks, but I wouldn’t even take it that far. And I definitely wouldn’t mention specific force field particles, like gluons. This will just draw you into quantum physics, and really the point here is to explain radioactivity.

Exploring the atomic nucleus is tricky (and abstract) enough – too much information will muddy the waters. We’re just building on the concept of force fields (gravity, electricity, magnetism, and now strong nuclear). If you have students who wish to pursue this on their own, here is an excellent website called The Particle Adventure:
https://particleadventure.org/

Part 3


So now we’re ready to talk about radioactivity as the result of the instability of large atomic nuclei, like those of uranium, or nuclei with too many neutrons. Basically there isn’t enough residual strong force out on the margins to hold these nuclei together.

An unstable nucleus will:
  • spit out single neutrons (neutron emission)
  • spit out single protons (rare)
  • spit out a chunk of nucleus made of 2 protons and 2 neutrons (alpha emission)
  • during these processes, the nucleus might also emit very high energy EM radiation (gamma emission)

All these emission products (particles, if you will) have a LOT of energy. If absorbed by other atoms, this energy can damage molecules and make atoms radioactive.

At this point, we are welcome to explore further anything we wish about radioactivity, including health effects or nuclear fission/fusion, or mass/energy conversion, or commercial nuclear energy, or what fuels the Sun. We have to keep it short and simple, though, because we’re not quite done.

Part 4


An unstable nucleus will also spit out – an electron! This is beta emission, and it's really weird. Why is this weird and unexpected? Well, where did the electron come from? Protons and neutrons aren’t made of electrons!


So there must be another force, another nuclear force. This one is called the weak force. The weak force is odd, though, in that it does not cause anything to happen, it allows something to happen. Here’s the something:


But there’s leftover negative charge and energy and mass. Where does it go? The weak force temporarily holds the charge, mass, and energy, and then releases it as an electron. So that’s where the beta emission comes from.

A neutrino is also emitted, but I don’t know how much you want to get into neutrinos, other than to say that they are especially tiny sub-atomic particles with no charge. They are often the result of energy converting into mass.

So here is what the full interaction looks like:


Conclusion


Ultimately all this is to say that there are only four fundamental forces in nature: gravity, electro-magnetism, and the two nuclear forces, strong and weak. And we might not ever have known about the nuclear forces if it hadn’t been for radioactivity.

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Satellite Blogging

Probably the most amazing Twitter account I have ever seen is the account of an inanimate object - a space satellite, to be specific. This satellite (and its companion satellite) tweets its exploits on a daily basis. here), and it has been in space for a decade.
The Rosetta spacecraft was designed to intercept a comet. It has spent almost all of the decade traveling out to the comet and lining itself up to join the comet in its journey toward the Sun. As I write it is in orbit around the comet and preparing to launch a small lander that will hopefully not bounce off the comet or crash into it, but instead spear itself into the surface and begin doing its science.

It's a very cute Twitter account, written as if the spacecraft itself was writing the tweets, and linking to a host of online resources - Twitter, Facebook, YouTube, blogs, websites, and webcasts. I've been an astronomy buff since I was 10 years old, so when Rosetta caught up with the comet finally this summer, I was quite excited. I'm always looking for a way to add astronomy to my physics classes.

Whenever I have a free 5 minutes or so in class, I put the Twitter feed up on the Smartboard so we can all have a look. The students feel my enthusiasm, and get pretty caught up in the excitement. They also think it's cool that I'm using Twitter and YouTube in the class. I've been doing this since the first week of school.
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