Bad Apple: A classroom skepticism quickie

Among the accepted truths of Watergate is that the Nixon campaign didn't need to do it. He was going to win the 1972 Presidential. There was no need to break into the Democratic National Committee offices; there was no intelligence that a Nixon campaign really needed. Nevertheless, break in they did. And Nixon eventually resigned as a consequence.

At the September 2021 Apple Event (California Streaming), the reality distortion field (RDF) was energized for a slew of new tech offerings. Among them, Apple Watch Series 7. The face of the watch was enlarged by a few pixels. But marketing is marketing. So to illustrate the significance of a few added pixels, Apple presented this image to demonstrate how much more text could be displayed.

The exercise is to show the image to students and have them tell you how Apple fudged this. Clearly, six or so more words appear on the newer model. The watch's screen only went from 44mm to 45mm (diagonal). Why so many more words?

What sorcery is at work here? With any luck, tech-savvy, skeptical teens will be able to knock a few holes in Apple's marketing RDF. Better still if they ever had to write a paper with a minimum page count requirement.

Should Apple have worried that without this dubious marketing exaggeration, Apple Watch sales would plummet, casting doubt on the future profitability of the tech giant? 

Given the facts in evidence, motivations and human nature, the Nixon camp still broke into those DNC offices in The Watergate.

My district bans a Jewish surname...

...from emails sent to district-managed student accounts. Here's the story:

In COVID-era Distance Learning, I have found Socrative to be a useful platform for administering student assessments. Among its useful features is the ability to send students their own individual scored test, showing which questions they answered correctly and which ones they answered incorrectly. The results can be sent to student email accounts with the push of a button. [You are correct to assume the instructor had to enter those email addresses into Socrative. But it's a one-time investment.]

This is a great feature for when we do Test Correction Journals.

But in my very first attempt to leverage this feature, it failed. I had, of course, tested the feature before using it with students. And it worked. But when I sent my students their test results, students insisted they did not receive them. I tried it using Chrome, I tried it using Firefox. Nothing worked. I had to create a privacy-respecting, individualized way to tell students which specific test items they missed. I created one breakout room per student, joined each one—one at a time, and announced which items they missed. While class time was burning.

I quickly came up with a functional workaround for the next period, but it fell short of what I needed it to do. And why didn't the student email solution work? 

Students suggested that the district blocks third party emails from student accounts. The vendor, Socrative, meets all legal privacy standards. District tech services said they do not block third parties. Further investigation indicated the emails were blocked because they contained objectionable content. That offensive content appeared in the following question. TW: "Objectionable Content."

[Secrets of the Psychics] Psychologist and former palm-reader Ray Hyman found that he had the greatest success with clients when he  

A. gave a straight-up reading in accordance with palm-reading guidelines 

B. told clients the opposite of what he saw in their palms 

C. imagined that he lived in an earlier era 

D. assumed his clients were skeptical of palm-reading and his abilities

There it is: the objectionable content, clear as day. What's that? You didn't see it? Look again. "hymen" is right in there. Prurient anatomical terminology titillation that would offend any community's standards of propriety. High school students must be protected from such filth.

Okay, not "hymen" exactly, but "hyman," a simple misspelling of a highly salacious, practically pornographic word. Okay, not "hymen" or "hyman" exactly, but "Hyman," a not uncommon Jewish surname. I presume my college hall mate's name, Steve Hayman would trigger that comprehensive filter, too, lest bad actors use simple misspellings to skirt content filters. 

Some might judge the content filtering of Jewish surnames (that are not anatomical terms) as anti-semitic. I'm confident the San Juan Unified School District doesn't intend it that way, but here we are. "Ray Hyman" triggered a full and immediate IP ban due to the district's sweeping content blocking protocols. 

I was given no reason to hope that this filter would be removed by my district's tech services, now that they are aware of the embarrassing error. It seemed as if the onus was on me not to include terms that would trigger bans, and I should just know what all those terms are.

The filtering is clearly far too aggressive and highly impractical. Blocking my instructional program (without notification) for the "crime" of including a Jewish scholar's name? That's beyond a bad look.

It's indefensibly paranoid and ignorant, in my assessment.

UPDATE: This is apparently just another instance of The Scunthorpe Problem, or as Tom Scott calls it, The Peniston Problem. 

Slow your roll

If you're not following Frank Noschese (@fnoschese) on Twitter, why even be a physics teacher with a Twitter account?

And if you get useful mileage out of constant velocity buggies (such as these from Arbor Scientific) but wish you had a convenient, reliable way to curb their enthusiasm, Frank tweets this:

These homemade battery spacers are amazing! Better than anything else I've tried (foil, paper clips, etc) to make a slow moving buggy.
* One flat-head machine screw (#6-32 x 2"))
* Two fender washers (1/8" x 1")
* Three #6-32 hex nuts#iteachphysics #modphys pic.twitter.com/r5gCvpSGJw

— Frank Noschese (@fnoschese) October 25, 2019

Today in "What not to buy"

This floated through my social media feed today...

The comments were appropriately brutal. And it wasn't the anthropomorphization that the commentariat was ruffled about. I suppose that's a risk inherent to advertising on social media. Your sponsored posts are subject to comments. At least they are for now. Facebook, Twitter, et al will no doubt figure out how to fix that so as to reap even greater profits. And why wouldn't they?

In any case, you could certainly acquire one just so that your students could rightly lambaste you during your lessons on circuits, if you're into that sort of thing. By the way, will we even be teaching circuits outside of AP and IB in the NGSS future? I don't see it in the high school physical science DCIs. But I could be wrong. Again, I digress.

Rather than supporting this electronic transgression with my hard-earned money, I downloaded an image or two of the offending item and will add it to the things we talk about when we talk about circuits in class.

But if you're keen to buy, here's the link: Science - You Complete Me

The Blog of Phyz is not responsible for short circuits, burns, or fires that may result from the use of this product.

One parent that should never be called back

I received an email from my office staff indicating a parent had called and wanted to talk to me, but I was teaching at the time. The parent requested I call her back.

When I did, it turns out she was a telemarketer keen to offer me a private business group travel "opportunity".

"I'm sorry: what is the name of your son or daughter enrolled in my class?"
"I don't have one."
"So you're not really a parent here, are you?"
"I have children."
"I don't appreciate your deception and am not interested in your opportunity."
"Do you know another teacher who might be interested?"
"If I did, I would not tell you. As we speak, I'm composing an email to my colleagues warning them of your deceptive tactics."

Thus ended the conversation. The email was sent out shortly thereafter. The blood pressure remained high for some time.

I get it: times are tough in the world of group travel sales. Maybe. But posing as the parent of a student to a teacher in order to trick them into calling you back is beyond the pale. It disrespects what we do and our commitment to maintain communication with parents.

I cannot imagine this tactic works for her, but if it doesn't why does she do it? She presents an example for those who consider "business ethics" to be an oxymoron.

Skepticism: Gwyneth's Goopy Body Vibes

Dan Burns recently directed my attention to a dust-up regarding a Goop-endorsed product. Goop is Gwyneth Paltrow's high-priced personal product brand/store and Body Vibes was an endorsed product available at Goop. Body Vibes' body stickers could work all manner of miracles

According to a Washington Post article, Body Vibes originally claimed to use materials engineered by NASA. After NASA refuted the claim, Body Vibes reworded their sales pitch to delete the NASA reference. Read the WaPo take-down for all the details.

If you thought Power Balance style scams were a thing of the past, think again. Body Vibes gets their "technology" from AlphaBio Centrix in Las Vegas. Watch this "disturbing" AlphaBio video. It was posted in 2015 and already had nearly 800 views when I came across it. (We can't all be Dan Burns.)



They had me at "We use sub-harmonic frequency to power our Bio Energy Patches". For such statements, we must deploy the most incendiary burn in the arsenal of physics: "Not even wrong". (For the uninitiated, that means it's so very wrong that it cannot even be considered as worthy of argument.) The genius of the product design and marketing is that you could get stickers for every need, from anxiety, to low-testosterone, to gluten free(?).

Bottom line: there will always be products like this and the products will always have a credulous customer base. Do what you can to make sure your students aren't taken in by these things.

Update: I almost forgot to include Stephen Colbert's Late Night take-down of Body Vibes.



Gizmodo's takedown: NASA Calls Bullshit on Goop's $120 'Bio-Frequency Healing' Sticker Packs

TANGENT: In the course of writing this post, I wandered over to what's left of the Power Balance company page. Not surprisingly, they're still selling bracelets. Waiting for that 2010 nostalgia craze to kick in, I suppose. Amusingly, the post-lawsuit "technology" behind the bracelet is described as "Power Balance holograms are created using a proprietary process featuring cutting edge three-dimensional imaging, which makes the hologram truly unique. The hologram is designed based on Eastern philosophies. Many Eastern philosophies contain ideas related to energy. These are commonly referenced as Chi or Chakras. There are a number of well known practices like acupuncture, meditation and Feng Shu, which are believed to affect these energies. The hologram is based on some of these same ideologies." A legal work of art!

Normalize Science

Most people that know me realize I'm a "science nerd," probably more appropriately described as a "science enthusiast." This means I enjoy talking about, reading about and encouraging others to learn about science. Most science teachers I know are enthusiastic enough about their subjects that they randomly insert science into everyday conversations. Sometimes this is greeted with "Hey that's interesting! Thanks for sharing!" type comments. Other times our science related comments are met with awkward science and a change of subject. This happened several times over the holidays and I was struck by how unusual it seemed to be to "talk science."

At both the extended family Christmas Eve and our neighborhood New Years Eve party I shared our plans for a family trip to see the Great American Eclipse next August. It is common when this comes up to have to explain to an otherwise well educated adult what a solar eclipse is and how it happens. At each holiday party I asked kids not "How's school going?" but "What are you learning in science class this year?" When the horn a child was blowing at a party seemed too loud I broke out the decibel meter app on my phone and reminded a mechanic friend to wear hearing protection at work.

My active and conscious support of science for all also presents with gift exchanges. I try to buy science or educational gifts for our family and friends, which I sometimes have to explain after they open it. For instance, this year I gave an Airzooka, a favorite classroom demonstration, to a family member who had received mostly gift cards from the rest of the family. As a young teenage boy he is now "difficult to buy for" and "doesn't want toys." As this video explains the Airzooka pushes a pocket of air that can be felt across the room. As soon as I assembled it for him he began shooting air at others across the room, and soon adults of all ages were stealing it to play with it. They had never seen anything like it, all wanted to know where to buy it and wanted to hear how it worked. Of course I was happy to oblige them and explain the science of it and how I use it to model sound waves in class. Family and friends were surprised how fun the Airzooka and other gifts were since they knew they were science and education related. Somehow labeling them that way came with the assumption that they couldn't be fun or couldn't be for younger kids. We've also given a drinking bird, geodes to crack, a moon night light with lunar phases, a solar robot toy, and more.

Luckily, other friends and families asked what my kids' interests are or if I have any specific ideas for them. They received many science and educational toys this year and I'm happy to report they are loving them all so far. Their Nana gave them Code-A-Pillars which allows them to build a robot caterpillar by connecting segments with different instructions on each. It allows students to practice rudimentary programming and learn sequencing. GG (Great Grandma) got my six-year-old a special viewing planter that allows her to see the plant roots as they develop. And a good family friend obliged when I said she really wanted a toy metal detector and she happily pranced around the yard listening to it ping.

While many science teachers already talk with their friends and family about science or give the gift of science, I'd love to see such practiced by non-scientists as well. A common phrase these days is "We need to normalize [X, Y or Z]." One way to normalize science for all is to talk about it. When someone around you asks "Why did that happen?" or "I wonder if..." discuss it with them, even if you don't know the answer. Encourage the young ones around you to be interested in science, even if they "don't want to be scientists." People like to cook, even if they aren't chefs. They like to go for bike rides even if they don't have professional equipment. I would argue that science can be an interest or a hobby for everyone. All adults can dabble in science without having a degree in science and they can encourage every child around them to do the same. Coloring became a viral sensation and the hobby-du-jour; let's make science the thing to do this year.

Understanding Even More Car Crashes

I posted a lesson to accompany the IIHS "classic", Understanding Car Crashes a few years ago. If that post doesn't ring a bell, click here. Links to the video and lesson can be found in that original post.

A related story percolated up through my social media feed a few days ago. National Public Radio's Goats and Soda produced a story about the Latin New Car Assessment Program (NCAP). NCAP ran a crash test that pitted entry level Nissan vehicles against each other: The American Versa vs. the Mexican Tsura.

Crash Test Dummies Show The Difference Between Cars In Mexico And U.S.

Here's the video:

2015 Nissan Tsura vs. 2016 Nissan Versa


[Executive summary: The American passenger fares much better than Mexican passenger.]

When news of the test went public, Nissan announced that Nissan Mexico would discontinue sales of the Tsura in a few months.

It could be that the timing of Nissan's announcement coinciding with NCAP's test was... coincidental. That is a real possibility.

On a tangentially related oldie-but-goodie, some folks think cars from yesteryear were tanks that would decimate today's light-weight counterparts. An instuctive crash test pits a 2009 Impala against a 1959 Bel Air. Watch the video to see how that one turned out.

2009 Chevrolet Impala vs. 1959 Chevrolet Bel Air


If you're a classic car enthusiast, drive carefully!

The lesson I constructed includes an exercise in which students look up the IIHS safety test of the car they drive (or are commonly driven in).

Rio2016 Olympics: Cupping

Others have covered this phenomenon extensively; such is the bright and microscopic nature of Olympics reportage. There are segues and human interest stories to be filed for the interstices of the wall-to-wall coverage.

What are those mysterious circles visible on athlete's bodies? The answer is: cupping hickies/bruises.

What is cupping?
CNN: Olympics in bright red spots: What is cupping?

Believers are convinced!
Cupping Resource: How does Chinese cupping therapy work?

Like most "alternative"/homeopathic practices, cupping offers anecdotal tales and theories for medicinal//performance value. Many are the stories; none are the clinical studies.

Cupping was addressed by skeptics long ago.
Skeptic's Dictionary: Cupping

Here's a newer takedown.
Insolence: What’s the harm? Cupping edition

A call for sanity is inevitably lodged.
The Atlantic: Please, Michael Phelps, Stop Cupping
Make no mistake: if deafness were an Olympic event, the ears upon which such pleas fall would win the gold.

Not only will Phelps continue to cup, but look for the cupping hickies on other athletes. All events; many nations. Trust that the practice will filter through to college and eventually high school athletes. Without the benefit of evidence, the practice offers a mystical advantage that promises adherents a competitive advantage. Who will dare put him herself at a "disadvantage" by not jumping on the band wagon?

The takeaway is that there will always be something. Some untested, evidence-free "edge" that athletes will flock to. Copper bracelets, magnet bracelets, hologram bracelets, aqueous metal-infused necklaces. This month: cupping. An objective observer might hope for some placebo effect. But that's all anyone can hope for.

There are many more links to be perused at one's leisure. If you see a nice one, let me know.

Quiet Fireworks?

Apparently I can't get enough of the sound of fireworks. NPR ran a piece on the science of the sounds of fireworks.


A pyrotechnician discusses how the sounds of fireworks are made and that fireworks don't have to be loud. Seems impossible but quiet fireworks are now available. My kids and I watched fireworks with some neighbors and most small children were wearing protective ear muffs like mine:

Each parent I talked to had a story about this kid or that kid being scared enough of fireworks to stay inside or cry or dislike the holiday altogether. Our family's dogs are typically sedated, left inside with the TV running and given lots and lots of treats. So quieter fireworks sound really good to me.

In a New York Times article about quiet fireworks they admit while these fireworks aren't completely silent they can be reduced drastically from their normal 150 dB to below the level of the accompanying music. Apparently, a small town in Italy actually passed a law that all fireworks must be quiet out of respect for their animals who can become agitated, scared or even run away.

Closer to home, military support groups distribute signs that say "A Combat Veteran Lives Here; Please Be Courteous With Fireworks." In some extreme cases the sounds can trigger violent attacks in veterans suffering from posttraumatic stress disorder (PTSD).

One article made the point that planned firework shows often don't trigger these PTSD attacks as the sufferers know that they are coming. The unplanned fireworks that surprise them are the ones that can bring on a PTSD attack. This is an interesting social justice point to bring up with your physics students. Does "having a good time" justify the suffering of others?

Given the potential for serious hearing loss for adults, even more so for children, the negative affects on local veterans, animals and pets I hope to hear about more quiet fireworks being used.

Fireworks Sound Safety

I just went to buy fireworks (kinda late notice I know) and noticed that all the promotional signs had a number ranking system for color, height, and sound.

The company has a 5 star ranking system for each category but I could not find information on their website about the corresponding decibel level. The National Council on Fireworks Safety, Inc. has a list of Recommended Safety Tips with no mention of hearing safety. Which is a shame because it is a missed opportunity to educate a lot of people.

Fireworks can be as much as 140 dB depending on your distance from them. And generally the bigger the firework the bigger the noise. Professional fireworks may be louder but they are also farther away from you.

I found that Dynamite Fireworks had more information about hearing safety on their "How loud are different fireworks?" page. I found their information both very detailed and accurate. I particularly like this gentle reminder:

"Since the decibel level to which you are exposed varies according to how far away you are, it only makes sense to step back several feet after lighting a consumer firework. The World Health Organization recommends that adults be exposed to no more than 140 decibels, which can be achieved by repositioning yourself a bit. Keep children well away from the spot where the fireworks will explode, as they should be exposed to no more than 120 decibels. It is best to keep infants away altogether, as they are highly sensitive to the physical effects of sound pressure."

Seriously, check out their page, share with others! They have lots of social media connections.

I also recommend the Noisy Planet website, from the National Institute of Health, for more resources on hearing damage, how to prevent it and how to engage your students in the discussion.

 

So what can you do? Well at a minimum plug your ears. A better bet is cheap foam ear plugs that can reduce it down 20+ dB. And the best option is to wear professional ear protection. If anyone teases you, just mouth "I can't hear you." 

The universe will end in one week—plan accordingly

Just a friendly reminder that The Mechanical Universe is scheduled to disappear from the Annenberg Learner web site / streaming host / purchase page after June 30.

A more complete version of this tale of woe can be found in a separate post. But if you hope to have continued access to these episodes, now is the time to act.

Loudest Sounds Ever

I was researching some articles about sound safety (great NY Times educators page to start you off here) and I stumbled upon this great interactive infographic about the loudest sounds.  It was created by an air conditioning company of all things, as part of their research into exactly how loud their products were compared to other things. As they say in the explanation, they might have traveled down a bit of a rabbit hole:

So we started to delve into the dark world of decibels to make the blinking things easier to understand. We initially wanted to create an amazingly informative infographic to best explain how loud our air conditioners are. However, we didn’t know where the ‘cut-off’ point should have been and we got somewhat carried away until we found the worlds loudest noise!

The Mechanical Universe is going dark soon!

We just learned from the Southern California section of the American Association of Physics Teachers that The Mechanical Universe will soon be disappearing from Learner.org. As of June 30, 2016, the series will no longer be available for purchase and will no longer be streamed (video on demand).

If you don't own your own copy, the series will cease to exist in a little more than a month and well ahead of the beginning of the 2016-17 academic year. The reasons are detailed in the SCAAPT article linked above.

The Mechanical Universe was produced in the 1980s at Caltech by a team led by physics professor, David Goodstein.  Each of the 52 half-hour episodes focused on a specific topic from the introductory college physics curriculum. Episodes featured high production values consistent with Caltech's proximity to The Entertainment Capital of the World.

The series was fairly exhaustive (outside of fluids, perhaps), and featured state-of-the-art computer animations. It followed closely on the heals of Carl Sagan's Cosmos, and it shares some video used in that iconic series.

Some critics would scoff at The Mechanical Universe's increasing age: 1985 was a long time ago. Others would scoff at the mere fact that the series engages in content exposition (unapologetically). I don't mind exposition from time to time (especially as review). And if an equally well-produced, thorough, and encyclopedic series with a fresher production date exists, please let me know about it.

A collection of expurgated versions of this college television course were "edited specifically for use in the high school curriculum." These were known collectively as the High School Adaptation. I do not have specific knowledge of their fate, but I expect it to align with that of the original series.

I have used high school and college versions of many episodes throughout my career, and would hate to be without them. I have developed sets of questions for students to answer while watching those episodes. Without distribution I fear the series will fade into the mists of history, as Goodstein might say.

The full set (52 episodes) is available for purchase for $200 via the Mechanical Universe page at Learner.org. The clock is ticking.

Worst (electric) shock of my life

I was recently reminded of a bad shock I took once, in the name of science of course. One of my high school students had really enjoyed our film can Leyden jar. He enjoyed dabbling in science on the side (who doesn't?) and made me a massive Leyden jar out of a pickle jar and a terra cotta pot. It is over a foot tall and while we presumed it was functional I was a new enough teacher that I did not want to try it out. It was covered in orange duct tape with "DANGER" written all over it. In fact, I hid it whenever there were substitutes in my room so no one would even be tempted.

Years later that same student came back to visit me, while studying physics in college, and we reminisced about his project. With another physics teacher in the room we decided to test it. We charged it up with my Van de Graaff generator and I touched it. It hurt. A lot. In fact I felt the shock all the way from my hand to my shoulder on the same arm. It was larger than I had anticipated and it hurt for awhile afterwards.

Now I regularly allow the current from my Van de Graaff generator to flow through a long aluminum rod through me to the ground while demonstrating. I try to avoid the shock from my dissectable Leyden jar demo but I'll take it if necessary. The shock from this massive Leyden jar was worse. By a lot. Now at least I can tell my students how bad the shock was and use it as a starting point to our discussion about shocks and safety.

It was my understanding that if the shock had been large enough to continue across my heart it could have been a lot worse. I would like to measure the size of the "shock" off of it, and the smaller Leyden jars I have students make but never have. I would think the large one would surpass my analog ammeter and RAFT multimeters. 

I recently posed this question to the Exploratorium's Teacher Institute Listserv to see if anyone had any ideas about how to achieve this. They agreed the equipment available to me would almost certainly be fried by my massive Leyden jar. The level of equipment necessary was apparently expensive and usually only available at universities and research facilities. Public high school: poor, fewer cool toys. Got it. 

The other take-away was that measuring the "shock" was difficult because there were many things to measure.  I show my students this table when we begin our electrostatics unit and continue to reference it through our current electricity unit. While the level of shock is often determined by current, as with this table, you can also measure the energy, power, capacitance and even the distance it jumps. The shock is incredibly short lived, however, making measuring it difficult.

I wanted to share my story as a cautionary tale and hoped to add, "If you wanted to test how bad the shock from a demonstration might be you should measure the shock before by [detailed safe procedures]." 

Since there is no easy way to do so I'll just say it's not a good idea because it really hurt.

A variable "tuning fork" with volume

Tuning forks have one job: to vibrate with a single fundamental frequency. Simple tuning forks are often troubled with some harmonics, but the overtones are typically very small in amplitude. The fundamental frequency produced by each fork is determined by its composition and physical characteristics. Most are made of aluminum, and their tone is fixed by the length of their tines.

Variable tuning forks have weights attached to the tines; the location of the weights can be adjusted. The frequency of the fork depends on the location of the weights. Such forks are okay in a pinch, but they're a bit dull for my tastes and their Q factor leaves something to be desired.

The good folks at Next Generation Science (whose corporate name is harder to find via search engine results in the NGSS era), offered an electronic tuning fork (Sound Generator) that could produce tones at 400 Hz, 600 Hz, and 800 Hz.

But wouldn't it be nice to have a small-scale, full-spectrum variable tuning fork? Perhaps you already do.

There are frequency generators aplenty available for smartphones. (I have FreqGen, but that one seems to have vanished from the iTunes Store.) What's important is that you can adjust the frequency of the output tone down to the hertz. You can turn your smartphone into a variable tuning fork easily enough. But much like a tuning fork, the smartphone's sound doesn't carry out to much of a volume. The common solution is to set the tuning fork into a resonance box.

But for the smartphone, that's where a portable speaker comes in handy. I have a Bluetooth speaker that is capable of achieving considerable volume. Once the speaker has been paired with the phone, you can unleash whatever frequency you like at volumes that can annoy people and animals for many meters all around.

I don't recommend blasting out 16,000 Hz at full volume simply because it cripples teenagers while leaving you oblivious. That's just cruel. Every time I do it, my students hate me for several minutes.

Use this newfound tool for good, not evil. It could be leveraged in a "speed of sound" type lab. I'll share my primary use for it in another post.

The Bells of Pasco

One of the first things I purchased for my physics program (using other people's money) was Pasco's Lenz's Law Demonstrator. At the time (1988), it was $55. I remember thinking that was a tidy sum, and that I should probably have cobbled together a home-made version of it myself. As my mentor, Steve Keith, often said, "Why buy something for $50 when you can make it yourself for $60?" But there I was, with the "store-bought" version and a bit of guilt.

The apparatus worked great for its intended purpose, but I felt it was important to milk this thing for all its pedagogical potential. I supplemented it with an otherwise identical length of PVC tube to show tubes made of insulating materials produced no effect, and I used an otherwise identical length of EMT to show that iron produced "too much" effect. (Who doesn't love a Goldilocks situation?)

Eventually, I found the aluminum tube did a great job as a blow gun: I was able to shatter whiteboard marker pens that I blew through the tube and toward solid doors or walls, accelerating the pens to speeds unlawful on local highways. The description of this application became my first published article in The Physics Teacher. The inimitable Don Rathjen of the Exploratorium Teacher Institute designed a simpler, safer version of this demo that he called The Marshmallow Puff Tube.

I also found that the tube was capable of producing lovely tones when struck gently at an end with a croquet mallet. The trick there was knowing where to hold the tube (with as light a grip as possible). Serendipitous experimentation shows that different tones can be produced, depending on where along the tube you hold it. The point is amplified if you hold the tube very near the end: acoustically, it's as dead as the proverbial doornail.

The other day I was returning our set of aluminum Pasco Introductory Dynamics System tracks to their storage space when I decided to give them a bonk with the old mallet. I was able to get a nice set of tones out of them. Not as pure and simple as with the Lenz's law tube, but not bad. The Pasco Basic Optics bench, though similar in its extruded aluminum simplicity, was a disappointment as a bell. I blame the permanently attached rubber feet for putting a damper on things.

What exactly one might do with the knowledge that a Pasco track is capable of producing nice tones, I do not know. If you think of something, please share it in the comments. If Bree or I think of something, we'll share it here, too.

And what about that $55 capital outlay in 1988? Considering it's been seen by over 150 students per year for three demos each year for at least 25 years, the expense amortizes out to $55/(150 × 3 × 25) = $0.0049 (less than half a cent) for each student per use in class. There are some things in education that cost more but are worth less. Whatever burden of guilt I attached to the demo purchase has long since been replaced by a buoyant spirit of instructional utility.

Why I no longer recommend the AP Physics exam

[This post carries the "rant" label, so it is presumed that your mileage may vary. I never presume my own experience is universal. None of this post refers to AP Physics C.] 

Since I began teaching Advanced Placement Physics B in 1986, I have strongly encouraged all my AP students to purchase and take the AP Physics exam each May.

For now, I am recommending that they do not.

As we know, AP Physics B has been re-imagined as AP Physics 1 and AP Physics 2. The old vision of AP Physics acting as a college equivalent was dispensed with in the redesign. AP Physics B (as well as content standards prevalent in the 2000s) were seen as too content-focused, and lacked emphasis on process. Not an unfair criticism, to be sure.

The newly redesigned AP Physics 1 and AP Physics 2 are ambitiously constructed, multi-layered visions of physics course utopia. They are Lamborghinis sent in to replace the Camaros that existed until now. College courses, for the most part, remain largely content-driven.

The vision of the AP course being a college equivalent has been abandoned. AP Physics 1 and AP Physics 2 are the best courses time, talent, and energy can buy. Meticulously crafted courses of physics perfection.

But as of now, it's beyond my budget. And beyond the budget of my highly capable students. It is very much in an experimental phase. Version 1.0 of a complex new machine that we have been asked to be the early adopters of.

There is evidence to suggest the nation's AP Physics 1 and 2 teachers and students failed to abruptly snap to The College Board's new vision. Scores between the 2014 AP Physics B administration and the 2015 AP Physics 1 and 2 administrations show a massive shift in the wrong direction.

In 2014, more than 60% of AP Physics B candidates passed the exam with a score of 3 or better. Of those, 34% passed with a 4 or 5 (over 15% were 5s).

In 2015, more than 60% of AP Physics 1 candidates failed to earn a score of 3 or better. Fewer than 20% of the candidates scored a 4 or 5 (only 4% were 5s).

It could be that America's physics students suddenly became less capable. But that's not likely. It's more likely that America's best and brightest physics students weren't prepared for the radically different new exam.

The College Board would argue that they provided extensive information on the newly designed courses. And indeed they have. Exhaustive, really.

But part of The New Vision is that there is no longer a blueprint for exactly what content is to be covered and in which amounts. Physics content mastery is no longer tested, it is now presumed. Instead of distributing questions across a well defined subject-matter topic list, questions are not cast across broadly-defined Big Ideas and Science Practices. Mastery of these can be assessed via questions that merely use physics content as the canvas upon which the Big Ideas and Science Practices are painted.

True mastery of the Big Ideas and Science Practices, via Learning Objectives and bits of Essential Knowledge, painted on the canvas of physics, demands a level of engagement I find to be unreasonable. Don't get me wrong, I'd love for my students to be single-mindedly focused on everything we do in physics: in class and beyond the classroom. But my students have other things going on in their lives that demand attention. Many, many other things, as is typical of highly capable, multi-talented college-bound students.

It is certainly The College Board's prerogative to offer a product for purchase as they see fit. But in my opinion, they got it wrong. My misgivings may well be mine, alone. But that's not the sense that I get when talking candidly to other AP Physics teachers. I assume some folks love the redesign. I trust they'll light me up in the comments because I have not talked to such folks in person.

Speaking only for myself, I would say The College Board did what most august bodies do when undergoing a revisioning process: they spent their time, talent, and energy creating a grand vision. With a multi-dimensional outline and hierarchy. A complex and ornate structure. They then committed that vision to a tome of well over 200 pages.

What would have been more useful to me is for them to have spent more time, talent, and energy developing valid practice items. Practice multiple choice, practice multi-correct, practice free response (all types). I am very much "an assessment guy," having served on AAPT's Editorial Exam board, California's Golden State Exam development team, and California's Content/Assessment Review Panel.

So my process is inductive rather than deductive. If you show me a large sample of assessment items, I can determine what your grand vision was. But if you show me your grand vision, I cannot figure out exactly what your assessment items will look like. Maybe others can deduce better than I can.

But I have yet to see a grand, sweeping process (including you, NGSS) that respects the value of assessment and released items. The spotlight is always shown upon The Vision. Pesky questions about assessment and released items are marginalized with responses such as, "We'll get to that later," "We don't have the budget for that," "The task of item development will be given to other people who are not part of the Blue Ribbon Visioning Panel".

AP Physics redesign advocates encourage teachers to participate in week-long AP training sessions, and I do not doubt that such trainings offer great value (assuming the time and money can be managed). I also know of someone who did the AP training and was left with the impression that rotation was a huge focal point for AP Physics 1. Workshops will always carry the biases of their instructors.

What's more, suppose a student does make a passing score on the redesigned exam. They've shown they can drive that Lamborghini with aplomb. As far as I know, colleges are no more likely to grant credit for the post-redesign exam than they were for the pre-redesign exam.

I'm already past TL;DR territory, so I'll wrap it up. For now, I cannot recommend my students pony up $100 to (most likely) end up on the wrong side of the cut points on an experimental exam. I'll do my very best to prepare them for the exam. But it's fair that they know the extent to which the odds are not in their favor.

With luck, there will be a time in the future by which a sufficient catalog of released items exists so that I feel comfortable that my students will be able to fare well on the AP1 or AP2 exam. But I have no reason to think released item development is a priority for The College Board. So I'll have to wait them out. I do not know how long it will take.

I do know of schools that are switching from AP1 and 2 to AP Physics C, and I know of colleagues who are looking for college credit alternatives to AP1 and AP2. I understand the motivations for these moves completely. To those who are delighted with the redesign, I wish only happiness and good cheer. And the hope that they realize their own experience is not universal.

Dial it down a notch

As a mom I am surrounded by noisy things. Not just my kids but their accessories. It seems every toy nowadays has a speaker in it and they rarely have a volume adjustment. Most of them are at a reasonable volume although they will still startle you if you unwittingly step on them.

Then there are the LOUD ones with volumes that can only be described in all caps. You can hear them sound across the house and they are the ones you hope bleed the batteries dead quickly. (They never are.) This game, in an unassuming cute telephone, starts as you pick up the handset and using the plastic tabs that reside inside you can play several games to practice counting, number recognition and more. Seems innocent, and educational right?

Wrong. The thing is LOUD. Loud enough to drown out any conversation while it is speaking. And it will speak as long as it wants, until you replace the handset. Which can come detached by the way, great design flaw. There is an on/off button but no volume control. So one night I had had enough.

I removed the tab holder that twists on to the bottom and removed four small screws that held the blue base to the white top. I found the speaker and was surprised at the size of it compared to the toy. Since I had two very upset children demanding, "Momma, why broken? Momma fix!" it was going to be quick modification without rewiring. After the fact I found this nice instructable with details on adding a resistor to lower the speaker volume. But Momma didn't have time for that.

Ideally I would have found a scrap of cloth to fit over the holes that the speaker fit up against but the lower lips were starting to protrude from my kids' faces. So I cut a few post-it notes and layered them over the holes from the inside of the phone. I think I ended up with five pieces of paper covering it with some scotch tape. The blue housing you see around the speaker slides into the space right in front of the post-it notes in the photo below. In retrospect if I had used cloth it may have been a tight fit getting the speaker back in its place. Upon reassembly it was noticeably quieter.

Now the children can play the game and I don't have to hear it from the other room. And I can present this problem to my students, perhaps as an open ended engineering thought problem. Since we build speakers in our electromagnetism unit (post sound unit and electricity unit) after they create one I can ask students how to lower the volume with a few restrictions:

1. How could you lower the volume by only changing the circuit? (lower current, raise resistance)
2. How could you lower the volume by only changing the speaker? (decrease magnet or electromagnet strength)
3. How could you lower the volume by only changing the outgoing sound wave? (impede the sound waves' travel to your ear)

I've already started a mental list of which other toys need this treatment. Perhaps my in-classroom school intercom ...

Newly expanded and updated Power Balance lesson

When transforming all my curriculum documents from Canvas to Keynote, my Skepticism in the Classroom Power Balance lesson was missed.

So over the break, I fired up the 2008 MacBook Pro running Snow Leopard, and rectified the situation.

The original was done before I came across ESPN's Outside The Lines exposé. And Power Balance has collapsed is meteorically as they rose, so I added a section on the still-in-business-for-now Phiten Company.

The assignment works nicely for flipped classrooms. It can be an in-class assignment if laptops and headphones (and splitters) are deployed.

YouTube Skepticism: Power Balance & Mylar Technology (2016 edition)

The lesson draws upon multiple videoclips. My favorite is a follow-up to a puff piece, wherein skeptic Richard Saunders has a Power Balance promoter do the debunking work on his behalf.



Here's an earlier version featuring James Randi similarly using a believer to debunk the charade. Make a note to yourself that promoter-administered strength/balance tests (applied kinesiology) are the calling card of many modern-day snake-oil salespeople. Fellow physics teacher and skeptic, Matt Lowry, and I encountered such a salesman at the National Science Teachers' Association national meeting in Chicago last year. We tried to be civil to the poor guy, but he really picked the wrong two conferees to prey on. The guy didn't appreciate it when I turned the tables and ran his own tests on him. My buddy, Matt, was so bent over with laughter, I thought he was going to lose continence.

Anyway, back to Classic Randi.



Did you see it? The instructive moment? It's actually a standard moment in nearly every public debunking storyboard:

1. Challenger makes extraordinary claim.
2. Challenger and skeptic agree on a testing protocol. This is a very important step. Very important.
3. Challenger fails test. Utterly and completely.
4. Challenger insists the extraordinary claim is valid, but the testing protocol was somehow "rigged".

How could Randi have preemptively robbed the claimant of her post-failure excuse?