The SAIL Teaching Framework

This is a condensed version of the complete chart, but it's a good place to start. Click for a larger view (and to download).

July 13, 2018

High (Voltage) Wire Act

Cross-posted from William H Calhoun



My brother-in-law Peter visited last year and showed me and my wife some of his favorite short videos on YouTube. When I saw this one featuring a man inspecting high voltage lines, I knew that I would show it to my students. It's a lovely little video narrated by the electrical inspector who talks about his work, and his life, and even tells a story about how his suit is a special kind of Faraday cage.

I knew my students would find this video interesting. There are a lot of intriguing electrical details and small events that could almost go unnoticed, and which could form the basis of some interesting physics questions and demonstrations. Our technical school has an Electrical Technology shop, and students in the shop would already know about this kind of work, and would be excited to watch this and share their knowledge. This video is a perfect example of what I like to add to my instruction toolkit.

The version I first watched on YouTube was of poor quality, and there was no indication of who actually made the video. It was obviously clipped from a longer video about dangerous or exciting work. There are many copies scattered throughout YouTube, and I spent a lot of time hunting for the best and most complete version. I finally found a high-definition version of the clip. I used Filmora to clean up the beginning and the end of the audio track. I did watch other videos about high-voltage line inspectors, but this one best suited my purposes. It's calming, actually, rather than all hyped up, and you get a sense of the man rather than just a focus on the details of the job. The music sets the mood perfectly. There's a joke at the end that mostly goes over my students' heads.

I eventually discovered that the the clip is from an IMAX movie called "Straight Up: Helicopters In Action." It was produced in 2002 by SK Films for the Smithsonian National Air and Space Museum, and apparently aired as a cable TV broadcast by INHD, which later came to be called MOJO HD. I also came across a comment that it had appeared on Discovery HD.

July 5, 2018

The Electromagnetic Spectrum

Cross-posted from William H Calhoun

A couple of years ago, when my team of physics teachers started building instruction around the topic of electromagnetic radiation, I began assembling a list of different common uses of EM radiation. This list would provide a basis of information to use in our written instruction, as well as suggest hands-on activities, demonstrations, and labs.

I focused on uses that high-school students would be familiar with; cellphones, wi-fi and bluetooth, radar guns used to clock car speeds, microwave ovens, various remote control devices, tanning lights. My school is a technical school, so students have familiarity with other uses and devices; arc-welding, dental x-rays, high-voltage power lines, baby monitors, visible light and color. By focusing on what students might be familiar with, I hoped to reveal both prior knowledge and prior misunderstandings and misconceptions. A teacher could build on the prior knowledge, but more importantly would be obliged to address the misconceptions.

The list became a full table of data, with over 30 entries. It has become an object of study in itself, an exercise in the literacy of reading data tables and extracting useful information to answer questions and solve problems. This is a form of literacy familiar to our technical students, who in their shops must learn to read technical manuals full of similar tables.

The full table is shown below:



As usual for me, the table was constructed as an Excel file, making it easy to add or change data. If you have access to Adobe Acrobat Pro, you could also edit the PDF version. Here are the links for both versions:

Excel file, with instructions
PDF file

A very helpful online calculator and table: https://rechneronline.de/spectrum/
Another online converter and source of information: https://www.translatorscafe.com/unit-converter/en/frequency-wavelength/

June 28, 2018

The Sun in Various Wavelengths

Cross-posted from William H Calhoun

My physics curriculum has shifted in response to our new state frameworks, and one shift has been a greater emphasis on electromagnetic radiation. I've been having fun concocting new examples and demonstrations (including an "in-house" field trip to our metal fabrication shop to experience welding).

This spring my class was having a discussion about the Sun's radiation, and how so much of what it radiates is invisible to us. They wondered what it would look like if we could see the different kinds of radiation. I explained that we can create devices or sensors that detect different wavelengths of radiation, and then construct false-color images from the information gathered. Immediately I went online and hunted for something to show them. A great resource, which I have used before, is the wonderful and painstakingly-built website called Windows to the Universe. This site is a project of the National Earth Science Teachers Association.

In particular, I went to the page entitled The Multispectral Sun, and found this animated GIF:


I liked this concept a lot, and looked around for other examples. I found What's the Sun doing lately? and Compare Multispectral Sun Images, and lots of imagery, including this NASA composite image from the Solar Dynamics Observatory:


I decided to try making something of my own. My project would be a video replication of the animated GIF above, but using many more images. And I would start with the images in the NASA image above.

Here is what I wanted: a video file so playback can be controlled, a broad and representative spectrum of images, and captions with either a specific or representative wavelength indicated. I shamelessly borrowed some aspects of the animated GIF (images scaled to the same size, captions colored to match the image, images taken on the same day). Because I started with the NASA SDO chart, I needed to know what date those images were taken. A little hunting revealed July 11, 2012.

So I was off and running. I decided to stick with spectroheliograms, rather than dopplergrams or magnetograms. I searched for quite a while for solar images in various wavelengths that were taken on 7/11/12. Depending on what time and from where the image was taken, 7/10/12 images sometimes worked as well or better.

As I accumulated my images, I had to decide on wavelength units. My students didn't know about Angstroms, so I used nanometers instead. I came to realize that I could use just three units; nanometers, millimeters, and meters. Then came the laborious Photoshop work, including colorizing a couple of the images. The video was constructed and edited with Filmora. I posted the final video on YouTube.

An interesting issue is the color of the Sun as we see it. Ask anyone, what color is the Sun? Almost everyone will say "yellow," but of course it isn't, it's white, at least to our eyes. (Please don't go out now and look at the Sun - it's bad for your eyes. But if you have a chance to look at it when it's obscured by fog or clouds, you'll see.) I found many images of yellow suns with the caption "visible light." These images were either taken through a yellow filter or they were colorized yellow because of a belief people will think it should be yellow (white light, of course, does not have a specific wavelength).

When I showed the final video to my students, they loved it. But many suggested it should have music. I was telling this to one of my fellow science teachers, and she said, "I have exactly what you need!" She owns a small, portable planetarium called Star Theater Pro, and it comes with a music CD having 15 minutes of suitably cosmic-sounding music composed by Donovan Reimer. She was right, it was perfect.

Here's the final video product:



And here's a shorter animated GIF:


Here are links for downloading the most recent versions:
MP4 Video: 4 seconds per image, with audio
MP4 Video: 4 seconds per image, no audio
MP4 Video: 3 seconds per image, no audio
Animated GIF: 2 seconds per image, continuous loop

Credits:

Radio: 0.9 m, 2.0 m - BASS2000/Nançay Radioheliograph
Microwave: 17.6 mm - Siberian Solar Radio Telescope
Microwave: 52.6 mm - Nobeyama Radioheliograph
Infrared: 1083 nm - HAO/Mauna Loa Observatory CHIP
Visible: 656 nm (Hα) - Big Bear Solar Observatory
Visible: white - NASA/SDO AIA
Visible: 393 nm (CaIIK) - Langkawi National Observatory
Ultraviolet: 170 nm through X-Ray: 9.4 nm - NASA/SDO AIA
X-Ray: 5 nm, 1.9 nm - NOAA/GOES Solar X-Ray Imager

Music - Star Theater Pro/Donovan Reimer

June 27, 2018

A Story About Weather and Teaching

Cross-posted from William H Calhoun

Physics as Story

I think of physics as a kind of story. It's actually a huge collection of stories, the result of working to understand every physical phenomenon under the sun (and beyond). In the physics classroom I am therefore a storyteller, and I endeavor to help my students become better physics storytellers.

Certainly in physics there's a specialized vocabulary that can be assembled into stories, but I also think of graphs, diagrams, and even equations as kinds of story. As with any good story, there is an art and a craft to both the understanding and telling of physics stories. Physics stories just happen to be demanding in particular ways.

High school students already know how to tell many kinds of stories. I teach juniors and seniors, and they tend to tell certain kinds of stories about the events in their lives. For instance, many of them have begun driving cars, or are about to, and there is a lot of interest in and concern about driving. Some have already had scary experiences and close-calls; few have an accurate understanding of the physics of what they are doing. A natural entry point, then, is to ask them about their driving experiences. Various instructional activities give them the opportunity to refine and change their stories. If a student can tell a solid physics story, by whatever means, to whatever extent, then that student is demonstrating learned knowledge of physics.

A Worksheet as Storytelling

An instructional tool I have used for a long time is the vocabulary worksheet. You know the kind - there's a word bank, and you fill in the blanks to complete the sentences. But my worksheets have a different twist. Most of the words in the word bank are used several times. Each blank is numbered, and if a word fits the blank, it fits all the blanks with that number. This allows me to avoid writing disconnected sentences with only one or two blanks. I can write a coherent paragraph, a whole short story. Sometimes toward the end of the worksheet the sentences are mostly just blanks waiting to be filled in. The repetition of words and phrases becomes an important part of adjusting to the new vocabulary.

After everyone finishes, we read the worksheet out loud, one student per sentence. Sometimes we'll go around the room twice. If there are diagrams or equations at the bottom of the sheet, interpreting them is part of the reading. The students really enjoy the challenge, even by the end of the year after we've done two dozen or so of these. Here's one:



These worksheets can be difficult to construct. I have written an Excel spreadsheet that helps me construct them. It allows me to just write the sentences as naturally as possible, while it keeps track of the blanks and the numbering and the word bank. You can download one here. You'll need to Enable Editing, and then Enable Content. Then click on the button labeled "Help."

The Story of Weather

So what about the weather? I have a few favorite physics topics, and weather is one of them. The problem with broad topics like this in the physics classroom is that students are struggling to learn the basic concepts and tools, and weather is a really complex topic. Still, whenever there is a good opportunity, I'll try to link some aspect of weather to whatever we're working on.

The topic of heat and heat exchange is central, for instance, to weather. Before students can begin to comprehend this story, they need to master some basic ideas and vocabulary about heat. In my classes, this work tends to happen toward the end of the school year. If I have a class that seems ready, and there's a bit of time in the busy end-of-year schedule, I have a special worksheet for them.

Or rather I've been planning a special worksheet for which there keeps being not enough time to finish and use. Not enough time for the last two years. This year, because I knew I had the students who could benefit from it, I really hustled to finish this special worksheet.

I started with a simple but long vocabulary worksheet which tells the story of how the interaction between the atmosphere and the sun's radiation results in a rainstorm. The worksheet is simple because there are only six words in the word bank! But there are 20 sentences. After I finished the basic worksheet, I got the idea to use diagrams of the entire heat process that would parallel the sentences. I used diagrams from the National Weather Service's lovely tutorials on weather called JetStream. I edited the diagrams with Photoshop, and then used Adobe Acrobat Pro to assemble my worksheet.

I decided to split the page vertically and have the running vocabulary/story part on the left half and the images on the right half. I then put fill-in blanks on the diagrams which corresponded to the vocabulary. Normally my worksheets are black-and-white, but I decided to keep the images in color and to print the worksheets using a color printer. This emphasized the "special" aspect of this worksheet (and the students who got a worksheet all said "Ooooh, color!")



While the students were working on it, I looped a time-lapse video on the SmartBoard that showed a collection of rain-clouds billowing way up into the atmosphere. It was the last vocab worksheet of the year. As usual, we read it aloud once everyone finished.

June 25, 2018

Quick Electromagnetism Demo Videos

Cross-posted from William H Calhoun

One of my students this past year had a medical condition that required him to be out of school for an extended time. In situations like this, I usually aggregate all the instructional material for a unit into a single file called a Portfolio PDF. Notes, homework, worksheets, quizzes, links to simulations, photos and videos of demonstrations and activities are all in one file. The student can either print everything out, or make changes digitally within the file and send it back.

Portfolio PDF's can only be read by Adobe Acrobat, so the student must download the free Acrobat Reader if it isn't already on his or her machine (as far as I know, the Portfolio PDF cannot be opened in Android and iOS devices yet). You need Adobe Acrobat Pro to create a Portfolio PDF - if you have access to it through your workplace, check it out. Acrobat Pro is worth the investment - get a student or teacher edition with a permanent license for a one-time fee (in other words, just purchase Adobe Acrobat Pro like in the good old days when you actually bought rather than rented software).

One of the units I packaged into a Portfolio PDF is about electricity and magnetism, and in particular about the various devices that take advantage of the E-M interaction. This is a difficult unit for my students, so hands-on equipment is the instructional tool of choice. What was I to do for my distance learner with no access to these devices?

I decided to make quick little videos for him, somehow. I had already been demonstrating the devices for my students, so the devices were out and ready, and I had my explanations practiced and warmed-up. I decided to use a simple Logitech USB webcam that normally attaches to my monitor. I experimented with rigging it up in various ways and hit upon having it point straight down at a black lab tabletop. That way just my hands and the devices would be visible while my voice narrated. The webcam software kept trying to adjust for the black tabletop, over-exposing anything not black. I finally decided to leave something bright in the frame which I knew I could crop out later. This turned out to be a pretty easy way to control the exposure.

After a couple of takes, I opened the video files in my editor of choice, Filmora (again, worth the expense), and edited the video. I created a fade from black at the beginning and a fade to black at the end. I separated the audio track, and faded the audio as well. I went through the audio to get rid of unnecessary um's and ah's and other sounds. Sometimes I inserted a bit of video or audio from another take. It was pretty quick work. I exported the videos as MP4 files and uploaded them to YouTube. The videos are below.














October 1, 2017

Aaron Baker

From Spoon Vision, the blog of Aaron Baker, an 8th grade U.S. History teacher in Oklahoma.

Those Who Can't


Those who can’t,
Teach.

For example,

Those who can’t sit alone at a desk all day,
Whose energy demands movement and interaction,
Teach.

Those who can’t abide platitudes like, “kids these days,”
Who take the time to know every young person,
Teach.

Those who can’t be satisfied with a job or even a career,
Whose everyday work must be filled with passion,
Teach.

Those who can’t look the other way while our schools resegregate,
Who believe the moral arc of the universe bends toward justice,
Teach.

Those who can’t stand by while our public institutions are privatized,
Whose collective conscience sees through the rhetoric of “choice,”
Teach.

Those who can’t ignore the history of organized labor in the U.S.,
Who know that “the union makes us strong,”
Teach.

Those who can’t punch a clock,
Whose passion can’t be confined to 8-4 or to August through May,
Teach.

Those who can’t care only about some children,
Who are committed to the success of every student,
Teach.

Those who can’t avoid conflict,
Whose acumen can diffuse the most hostile situations,
Teach.

Those who can’t be happy climbing the corporate ladder,
Who will master their craft, and stay in the classroom for decades,
Teach.

Those who can’t settle for anything less than constant improvement,
Whose minds are always searching for innovative new methods,
Teach.

Those who can’t quit,
Who will continue to educate more students with less money,
Teach.

But please know.

Those who can’t be fooled by political schemes,
Whose organizing can create a political revolution,
Teach.

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.

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 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 just 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: http://www.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 out 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.

Cross-posted to Teaching and Instructional Design