In the George Floyd trial: Audio Pareidolia

Humans are so good at finding patterns, we often find patterns where none exist. This phenomenon is referred to as pareidolia. 

Add to this the power of suggestion, and things get even more interesting. The back masking panic was fueled by audio pareidolia. As was EVP: electronic voice phenomena, a means by which ghost hunters fool themselves and others.

I made a presentation on the audio version of this phenomenon and deployed it during our unit on waves and sound.

It was all good, wholesome, laughable fun. And then it showed up in the trial of Derek Chauvin. I have updated the presentation to reflect this latest incident. I placed it at the vary end so that by the time you get there, you'll recognize exactly what's going on.

Back Masking (HTML export)

RT;DL Introductory Wave Activities

At this point, I think we all have our own favorite PhET sims. You might be able to start a fight among physics teachers by proclaiming your favorite is the best PhET sim of them all. But honestly, what's not to love about John Travoltage? 

Actually, I think Wave Interference is my favorite. (Energy Skate Park fans are now unfollowing me on Twitter.)

When we get to wave optics, we use the light module to develop interference pattern mathematics. As we begin the study of mechanical waves, we explore representations in the water wave and sound modules.

Water Waves in an Electric Sink at Teachers Pay Teachers
Students begin with examining a pulse with the sim's various view modes. Then it's on to continuous wave trains while varying frequency and amplitude.

High Quiet Low Loud at Teachers Pay Teachers
Originally developed for use with Pasco's Waveport DataStudio software, this activity has been redesigned around Wave Interference's sound module. This time, the manipulation of amplitude and frequency is accompanied with audio feedback. The sim's "Particle View" feature shows that matter doesn't move much even as a wave propagates across greater distances. Diving deeper, we notice that our sound waves appear to be moving through a solid in the sim.

I couple these with The Mechanical Universe - Episode 18: Waves and Paul Hewitt's Conceptual Physics Alive! Vibrations and Sound I and Vibrations and Sound II to round out much of the introduction to waves.

In any case, I'm sure there's even more to PhET's Wave Interference than I am leveraging. So much groovy wavy goodness!

PTSOS Workshop 2 Links of Phyz

Here are some notes and links relevant to PTSOS Workshop #2. If you're new to teaching physics in Northern California, check out PTSOS.org.

Momentum and Energy
I prefer momentum before energy, but I've run into teachers who consider those to be fightin' words.

Phyz Momentum Curriculum

One highlight here is our Grass Omelette (Egg Toss Competition). In 2013, I had five sections of Physics, so I was able to compile an adequate set of images and video to make a tidy video: Egg Toss 2013

Phyz Energy Curriculum

If you're a fan of ranking items, you might enjoy
Potential Energy Ranking - Answers
Kinetic Energy and Momentum Rankings

Further distinctions between kinetic energy and momentum are explored here.
Kinetic Energy and Momentum Conundrums - Answers

For video resources, there's
The Mechanical Universe High School: Conservation of Momentum, and Conservation of Energy
The Mechanical Universe (College): Conservation of Energy, Potential Energy, and Conservation of Momentum.

Waves and Sound
Phyz Waves Curriculum

One of my favorite lessons is a nice foray into skepticism: Back Masking and EVP (Drop Box Link to Keynote Presentation). I connect it to a lesson that involves Musical Roads and Talkie Tapes.

Demo: Science is Fun!

For video resources, there's
The Mechanical Universe High School: Introduction to Waves
The Mechanical Universe (College): Waves
PBS: The Secret Life of Waves

The Waves and Sound Playlist of Phyz

Here's the latest Phyz playlist, an idea I got from fellow Phyz blogger, Dan Burns.

The topic this time is waves and sound.

Curiosities: An alphabetical listing is dominated by the Ws. A chronological listing is dominated by songs released in the past five years.

Left behind: The list would be longer if not for careful curation. Apple Music search results tagged with an E (explicit) are not included. We fire up the playlist (at an Office Space "reasonable volume") during lab activities. You do not want to fill your classroom with expletives, no matter how mellifluous the tones. Because that will be followed by a conversation with your principal that you really do not want to have.

In any case, on to the list. If I missed a gem, let me know in the comments. I like that the alpha list begins with "Catch a Wave" and ends with "Waving Goodbye".

The Waves and Sound Playlist of Phyz
SONG	ARTIST	YEAR
Catch a Wave	Beach Boys	1963
Don't Make Waves	Brand X	1979
Every Breaking Wave	U2	2014
I Like the Sound of That	Rascal Flatts	2014
Salt Water Sound	Zero 7	2002
Sound	Daniela Andrade	2016
Sound	James	1998
Sound & Color	Alabama Shakes	2016
The Sound	The 1975	2015
The Sound of Silence	Simon & Garfunkel	1966
Veering From the Wave	Jennifer Kimball	1998
Walking on Sunshine	Katrina & the Waves	1985
Warm Sound	Zero 7	2004
Wave (Instrumental)	Antônio Carlos Jobim	1967
Wave (English)	Sinatra & Jobim	1967
Wave (Portuguese)	João Gilberto	1977
Wave	Beck	2014
Wave	Brooke Butler	2017
Wave	Jvck James	2018
Wave	The Midnight	2018
Wave (feat. Kali Uchis)	Major Lazer	2015
Wave (feat. Masego)	Abir	2016
Wavelength	Van Morrison	1978
Wavelength	Lastings	2015
Waves	Mr. Probz	2014
Waves	Blondfire	2014
Waves	Dean Lewis	2016
Waving	The Bevis Frond	2016
Waving	Blackfield	2011
Waving	The Delilahs	1995
Waving	Jami Lula	2002
Waving	Rich Whiteley	2009
Waving	Tamas	2017
Waving	Tiny Desserts	2019
Waving Goodbye	Sia	2016

Click the "playlist" label below to see more Playlists of Phyz. As of this post, there are playlists up for Electricity and Magnetism. 

Physics Girl's twist on polarized light

If you're not subscribed to Dianna Cowern's Physics Girl channel, you should fix that as soon as you can.

She's got a nice episode on polarized light that covers the basics and extends into ... things I didn't know! As Paul Hewitt would say, "Yum!"

Take a look for yourself. If you already knew about human visual sensitivity to polarized light, you're ahead of me. (Not really a high bar, but still...)

Physics Girl: Only some humans can see this type of light


It was so much fun, I wanted to show it in class when I teach polarized light. Of course, I have that condition (?) that compels me to write up a questions set that students complete while they watch the video (and a bonus question for after).

That question sheet can be found at the link below:
YouTube Physics: Only some humans can see this type of light @ TPT

Structural color in Morpho butterflies

KQED's Deep Look produced a nice piece on the structural color seen in iridescent colors in organisms.

What Gives the Morpho Butterfly Its Magnificent Blue? | Deep Look


And what good is a video clip without some questions to keep gawkers engaged?

YouTube Physics: Magnificent Blue @ TPT

Why California's musical road sounds terrible

When Honda produced a musical road in Lancaster, California a few years ago, I linked to their commercial and developed a lesson that included it. A Blog of Phyz post was duly posted.

The off-key result (and a bit of auto-tuning) bothered me. And I certainly didn't keep that a secret. I assumed it was an implementation error of some sort, and tried to invoke the notion that, "It's not that the dog sings well, it's that the dog sings at all!"

Creative science YouTube content creator, Tom Scott, did the legwork, er, wheel work to get to the bottom of this grooviness gone awry. It boils down to "centers" vs. "gaps". Take a look.

If you spend time distinguishing between random and systematic error, you'll want to add this to your curriculum there.

Why California's Musical Road Sounds Terrible


Scott refers to his source: Caltech's David Simmons-Duffin. Here's the well-crafted and thorough article posted at DavidSD.org way back in 2008. It really is well done, and he calls out Honda for auto-tuning the last two notes of the road, as did I. Spend some time and enjoy this post:

Honda Needs a Tune Up

Colored Shadows Tough Problem

I have mentored and coached for the New Teacher Program through the Exploratorium's Teacher Institute for several years now. Many summers I get to work with teachers in their first few years of teaching as they participate in an intensive three week institute. I went through it myself ten years ago and it is a lot of great information and wonderful pedagogy. I learned more in those three weeks than in my entire credential program about teaching science.

It is exciting when a new teacher discovers or comes up with something that is so cool it has be shared. Summer 2016 Ajayi Lawrence was focused on light and took a journey through diffraction, color addition, filters, etc. There were several times that we took red, green and blue LEDs to darker exhibits to experiment. Lots of "Oh that was cool, do that again!" and talking out what we saw, especially when it was contrary to our predictions. (It's good to be wrong sometimes!)

While trying to set up a procedure for his students, Ajayi shone a red LED through the two filters of a pair of 3D glasses. The red light passed through the red filter and was almost completely blocked from the blue-ish filter, as expected. The blue light was blocked by the red filter and shone through the blue-ish filter. The green light was blocked by the red and shone through the blue-ish filter. (Now you seen why I say it was "blue-ish.")

Later we took the same pair of glasses to the Colored Shadows exhibit (which can be recreated in your classroom using this Science Snack) and snapped this great picture.

 

Ajayi and I both said that showing this picture to students and asking them to determine the colors of each filter would be a great way of  assessing what they have learned about color addition and subtraction. This year in our color unit I showed this picture to my students and didn't tell them that they were 3D glasses. After some discussion they realized that the two lens of the glasses must be different, which reminds them of "old" 3D glasses. Most of your students will have never used red-blue 3D glasses before, by the way. After they discover that they have to think about what light passing through one of those filters would look like versus lighting being blocked by the filter. 

This was done as a quick end of class activity to wrap up some other concepts. I would have preferred it to be discussed in small groups with whiteboards so that students could make their own drawings. I've written up a worksheet that is a little more guided, adding a portion on the colored shadows of hands I already use, that is available untested as a pdf. If you want to check your answer here is a visual key.

Finding the speed of light with Peeps

I heard a piece on this on NPR. Very cute. Some do this with chocolate, and other materials can be used. But in the event you have leftover Peeps hardening around the house...

Chladni Singing

Chladni plates are a beautiful and dynamic example of resonance in two dimensions. Originally a bow was used (as seen in this Harvard demo video) to create two dimensional standing waves in a flat piece of metal in different shapes. More common now is to use a frequency driver to control the frequency of the standing wave. Here is a video that goes through a wide range of frequencies:

Whatever the method, you can demonstrate that higher frequencies produce shorter wavelengths and thus smaller patterns on the plates. You can talk about the fact that the pattern on the plate seems to abruptly change as a resonant frequency is reached. Ask students if the locations where salt gathers are nodes or antinodes of those standing waves. There is a lot to learn from something that is also mesmerizing to watch. If you're not super comfortable with the explanation yourself try showing your students this Physics Girl video that has a good explanation and information on the next steps in modern science.

I thought I'd seen everything about Chladni plates (including this music video they appear in) but then I learned of someone who can sing to a Chladni plate! Meara O'Reilly works at the Exploratorium museum of San Francisco and has enough voice control to sing to Chladni plates to create different patterns. Her website devoted to this phenomenon is here and an example is below. While amplified, this is produced by the human voice and not a frequency generator. It is amazing.

Heavy metal music?

I recently watched the local Bay Area Revelations episode "The Two Towers" which told the parallel history of Cal Berkeley and Stanford University. The whole journey was interesting with lots of historical facts I had never heard. For example, famed Stanford marching band director Arthur (Art) Barnes composed most of the music for the marching band from popular rock & roll songs of the 1960s and 1970s. During the interview Barnes said that he would listen to the song he needed to arrange over and over again. One in particular was in E Sharp (E#) which was too high for many of the instruments, so he decided to write it in E Flat (E♭). In order to hear what this would sound like he attached many quarters to the needle of his record player, weighing it down and forcing it into the record. He said it ruined the record but lowered the pitch of the song for him.

While looking into the more common "penny trick" I found most posts were in the form of: "Don't EVER do this!" Seen as a quick fix "life hack" to stop a needle from skipping audiophiles condemn this behavior because of the potential damage to the needle and record.

This Colored Vinyl Records Blog post details why this "penny trick" is a bad idea:
"Adjustable counterbalance is an essential feature to look for when choosing a record player. Usually this is a rotating tonearm counterweight with which you can independently adjust the tracking force of your needle (the amount of vertical pressure keeping your stylus against the surface of the record). Precise tracking force is important for the quality of sound and to prevent damage to your stylus and your records. If it's set too heavy, your stylus will be too light and will cause the record to skip. If it's set too light, your needle will be too heavy and while it will track your vinyl well, it can cause damage to the grooves of the record."

A few people said that you could use a penny to add to the mass (not the weight) of the cartridge and stylus end but it would have to be appropriately counterbalanced on the other side. I found no mention of changes in frequency; but many report better tracking of the stylus.

I remember my dad's record player had a switch for playing a few standard speeds for different size records: 33.3 rpm, 45 rpm and 78 rpm. If you accidentally used the wrong setting you either got a very low Barry Mannilow version or it sounded like the Chipmunks. [More on the concept can be found in this Popular Science 1950 post about how to make your own variable frequency generator so your old turn table could play newer records.] My best guess is that as Barnes weighed down the stylus with quarters he was causing it to dig into the record enough to slow it down. This caused the frequency to drop as a function of the speed change but not enough to hear a tempo change in the song.

The exact frequency of an E# depends on the octave of the instrument you're playing. According to this diagram of frequency vs position on treble clef (name of note) there is not much of a frequency difference between the two. From mid E to F (same as an E#) the frequency rises from 330 Hz to 350 Hz. From a D# (same as an E♭) to a mid E the frequency rises from 310 Hz to 330 Hz.

What does that sound like? Here are two seconds each of 310 Hz to 330 Hz to 350 Hz so you can hear the shift.

How much did Barnes record slow down then? I can't put quarters on my dad's turntable to repeat the experiment; I might be disowned. But I can play with the speed a record is played at. My next step is to play a record with hopefully a pretty constant frequency at the different rpm settings and measure the changes in frequency.

Any other insight into this would be appreciated in the comments.

EDIT: Thanks to Al Sefl of San Francisco for sharing that there is a direct relationship between the frequency we hear and the speed of the turntable. Running a 33.3 rpm record at half the speed results in half the frequency. Therefore dropping the 350 Hz E# to the 310 Hz E♭ could occur from dropping the 33.3 rpm to 29.5 rpm or so. So it is conceivable that the additional weight from the quarters weighed the stylus down enough to drag the record and slow it down. Still not a great idea.

YouTube Skepticism: Cell phone popcorn

In late May, 2008, a set of videos were uploaded to YouTube that were soon to go viral. Each one appeared to be a handheld video capture of a group of enthusiastic twenty-somethings conducting a home-made experiment to see if cell phones could be used to pop popcorn.

The cell phones are arranged to focus their energy at the few kernels of popcorn. The phones are then simultaneously called, apparently by a second set of cell phones these casual friends happened to have on hand. After the phones begin to rattle and ring—but before they go silently to voicemail—pop go the kernels! Take a look.

Pop corn with cell phones (American)



Pop corn with cell phones (French)



Pop corn with cell phones (Japanese)



My award for the greatest display of enthusiasm goes to the Japanese video. The notion of popping popcorn with cell phone radiation swept the Internet's imagination, and people tried to repeat the experiment around the world.

They all failed. Without exception. But it had to be real, it was a video on the Internet! (Ah, the innocence of 2008.) Speculation arose that specific cell phone brands had to be used. Some thought there was a hidden heating element at work. Others correctly deduced video editing shenanigans.

The complete worldwide failure among those who tried to reproduce the demonstration speaks nicely to a key principle in science: reproducibility.

It was later revealed that the videos were a stealth marketing campaign produced by a manufacturer of Bluetooth headsets. The president of that company denied that the intent was to suggest that it might be smart to use a headset and keep the microwave cooker of a cell phone away from your brain. (Medical evidence suggesting cell phones cook brains is not compelling.)

Eventually, the Internet moved on to the next viral video. Was it Microsoft's Megawhoosh featuring even more bad physics? Mythbusters didn't even bother with cell phone popcorn, but Brainiac Science Abuse did.

It's worth remembering such hoaxes. Looking back, there are easy-to-spot tell-tale signs of hoaxterism. So of course, I wrote a quick YouTube Skepticism lesson to probe this set of videos and its raison d'être.

YouTube Skepticism: Pop Corn with Cell Phones @ Teachers Pay Teachers

The larger point isn't that this particular hoax needs to be debunked but rather that there will always be a next one. If students can recognize fakery in classic hoaxes, they'll be prepared to cast doubt on new ones.

Hoaxers are nothing if not consummate recyclers. Copper bracelets become magnetic bracelets become hologram bracelets become aqueous titanium-infused necklaces and so on and so on.

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!

Ice Scream - a new ExploratoRio Science Snack

When broadcast television was something people watched, networks would pitch their "encore presentations with the line, "If you haven't seen it before, it's new to you!"

Somewhere in the running conveyor belt that is my Facebook feed, I recall seeing a video of a Kennedy half dollar coin being set into a cavity in a chunk of dry ice. The coin and ice produced vibrations and sound.

When two students ran me through the paces of their Bubble Suspension build (for our upcoming ExploratoRio2016 on Wednesday, April 13), they left some dry ice behind in my classroom sink.

So it's me, some sublimating dry ice in a sink, and no one else around. Recipe for serendipity if ever there was one.

After dousing the frozen carbon dioxide and blowing the subsequent cloud out of my sink a few times (that never gets old), I found a nearby electrophorus and pressed it into the sublimating mound.

What happened next is best relayed in the form of a video, which drops the action to 1/8th speed at about 20 seconds in.



So unexpected was the sound that I decided a new ExploratoRio Science Snack was in order. The title of "Ice Scream" wrote itself with little help from me.

The details (as much as I know them or foresee them) are in the recipe linked to below.

Ice Scream - ExploratoRio Science Snack.

Note: Adopting the look and feel of the original Exploratorium Science Snackbookq was not an accident.

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.

New video lesson—The Physics of Tavurvur Volcano

A video similar to this one made it into my Facebook feed, and I saw fit to turn it into a YouTube Physics lesson.

Mount Tavurvur Volcano Eruption Papua New Guinea 2014 (Extended Version)

So much physics. How could I resist?

There's the ability to use the sights and sounds to determine distance from the volcano to the camera.

There's the projectile motion of the ejected boulders. Launch speeds, maximum ranges, maximum heights—start with ideal estimates.

Then use PhET's Projectile Motion sim to bring air resistance into the analysis. Huge differences!

Are the spectators at a safe distance? No need to wonder: find out how far those boulders could fly for maximum range. And maximum range with air resistance doesn't happen with a launch angle of 45°.

And don't forget about the adiabatic expansion cloud that appears and disappears at the outset.

Here's the student worksheet that I prepared. The lesson can be done in or out of class. 

YouTube Physics: Tavurvur Erupts! @ TPT 

The answer key is available to classroom teachers who send requests from school email accounts. Ask for the Tavurvur Answer Key.

Here's PhET's "Projectile Motion" sim page.

PhET Projectile Motion 

Dark Energy? No! It's A Crazy Pool Vortex!

Physics Girl's Crazy Pool Vortex

So many physics… What's not to love?

I like that the image in the poster frame bears a striking resemble to the FSM. Coincidence? Perhaps.

Standing. Water. Waves.

My students, Andrew Stephens, Joey Cozza, and Jeric Rocamora are highly accomplished musicians. They were inspired to blend physics, music, waves, and optics by something they saw on the Internet.

Here's the video record of their inspired work.

Physics - Waves Water Experiment


Pretty groovy, right?

Of course, you don't see these structures when watching with the naked eye. You only see them when they are captured in frame-rate-specific video.

The iPhone app they were using is the free FreqGen.

Here is the video that inspired them.

Amazing Water & Sound Experiment #2


I think this one benefits from brighter ambient light. This allows a faster shutter speed. Filming at 24 fps doesn't mean the shutter is set to 1/24th of a second. And a faster shutter (1/500 s) allows for a sharper capture.

When I first saw this, it wasn't clear to me what was going on. And it's not unhealthy to assume anything that looks supernaturally groovy on YouTube is likely a fake. Captain Disillusion debunks video fakery all the time.

But what we're seeing in these videos is artfully captured stroboscopic effect. The classic example is the wagon-wheel effect. Here's a nice video of an "impossible helicopter." The wagon wheel effect is not the same thing as the rolling shutter artifact.

Here's a thorough explanation of the difference between the classic wagon wheel effect and the newer rolling shutter artifact.

I'm pretty sure I promised them a post on The Blog of Phyz. Consider yourselves famous, guys! You even scored the highly-coveted "groovy" tag.

Harmony and dissonance: More on the singing roads

HARMONY
When I developed the "Science is Fun!" activity discussed below, I should have known that Honda's Musical Road in Lancaster was not the only musical road in the world.

It turns out there at least four. And there's a web page devoted to the phenomenon. It's part of the Sound Tourism website. Want to drive them all? Pack your bags! Here's where they are:

1. Lancaster, California, USA, Musical Road - "William Tell Overture"
2. Melody Road, Japan - "Memories of Summer"
3. Anyang, Gyeonggi, South Korea - "Mary Had a Little Lamb"
4. Gylling, Denmark, Asphaltophone

There's a nice "video jukebox" on the page that allows visitors to see news clips relating to each of the roads.

DISSONANCE
If you listen to the Musical Road as depicted on the 2009 Honda Civic Musical Road ad, you hear one version of tarmac William Tell Overture.



If you listen to posted YouTube videos of "regular folk" driving the Musical Road in Lancaster, the tune is significantly different. And not for the better.



Did Honda autotune the road song for their ad?

According to the Musical Road page on Wikipedia, the Lancaster's tuneful tarmac was moved from one location to another due to complaints of local residents about the noise.

The timeline was as follows: in early September of 2008, Honda's Musical Road opened. In late September, it was paved over. In mid-October, the musical road was reconstructed in a location farther from residents. Perhaps the September road was better and the October road was worse.

The location shown in the Honda ad appears remote; the location in the YouTube videos appears remote. But the tune in the everyman videos is quite off.

The Wiki page review is less kind: "The rhythm is recognizable, but the pitches are so far off that the melody bears only a slight resemblance to the William Tell Overture. ... It is likely the designers made a systematic miscalculation which affected all the groove spacings."

And that was the review of the "good" version from the ad. My own take is more forgiving. Remember, it's not that the talking dog speaks well, it's that he speaks at all.

UPDATE: Sound files offered as evidence of Honda's auto-tuning.



User Finale (with a 20% speed increase to match Honda's higher-speed pitch)



UPDATE: This one appears to be in the new location. And the banter between our investigators is too cute not to include. It sounds that same as the "original" road, with the same off-off-notes, so I'm sticking to my theory that Honda auto-tuned certain notes in their TV ad.