Fibonacci zeotrope sculptures

Sorry for the sudden aggregation binge. I should be working on my genuflection to The College Board (AP Physics 1 and AP Physics 2 syllabi), but my motivation for that exercise is so. very. low.

In the meantime, let's enjoy this confluence of Fibonacci numbers, 3D printing, and stroboscopy, shall we?

This San Francisco Globe article introduces it nicely.

And, of course, video.

Fibonacci Zeotrope Sculptures


Fibonacci Zoetrope Sculptures from Pier 9 on Vimeo.

"These are 3-D printed sculptures designed to animate when spun under a strobe light. The placement of the appendages is determined by the same method nature uses in pinecones and sunflowers. The rotation speed is synchronized to the strobe so that one flash occurs every time the sculpture turns 137.5º—the golden angle. If you count the number of spirals on any of these sculptures you will find that they are always Fibonacci numbers.

For this video, rather than using a strobe, the camera was set to a very short shutter speed (1/4000 sec) in order to freeze the spinning sculpture."

Two men in conductive suits climb Tesla Coils—What happened next was truly shocking!

Can I write a Buzzfeed-(up)worthy click-bait headline, or what?

Anyway, what to do if you have skills in electrical engineering, dance, and martial arts?

Ladies and gentlemen, the Lords of Lightning.

Lords of Lightning (Official HD)

Momentum Mobile: Have you seen this equipment?

Demonstration or lab equipment for physics classes can vary from homemade of scraps and junk to store bought and polished shiny pieces. I believe there is a place for each in the classroom but sometimes there is no beating a truly well made purchased piece. An advantage to purchased pieces is that they often stand the test of time and are used year after year (or decade after decade depending on your teaching experience).

Many of us keep a "wish list" of sorts for our classrooms. This may be mental or you may actually have a collection of marked catalogs or ripped out pages. A wise physics teacher (*cough* Dean *cough*) once told me that keeping such a list could help get equipment for your classroom when random money falls from the sky. While it doesn't quite rain I have been lucky enough to have such lists ready at the end of the fiscal year or at the beginning of a new program when an administration is asking for things to buy. That's right, sometimes they ask us and you better be ready!

Yet sometimes you know just what you want to buy but you don't know where to find it. It may have been something you saw at a conference or in a catalog somewhere sometime and you can't quite place it. Whatever it is you just know, "If I had this then my students would completely understand [insert tough concept here]." Perhaps the most frustrating part is that you know the equipment is out there, somewhere, you just don't know where to look. But someone does; maybe avid Blog of Phyz readers?

Another Physics teacher in my district recently said that he wanted this momentum cart he had read about years ago. The cart has a slanted back (higher at the front, lower at the back) and marbles or ball bearings are placed in it. At the start the marbles are stopped from rolling out with a hand at the back of the cart. When you remove your hand the marbles start to roll out and because of conservation of momentum the cart starts to move forward. The marbles fall out one at a time and as they continue to fall the cart speeds up. The teacher said that he thought he remembered the second to the last marble would be the fastest and then the last marble is at rest. This part did not make sense to me but we will have to get the cart to experiment with.

I made this simple image based on his description and he said it looks like what he had seen but didn't know where to find one. Over the years a few students have tried to make it but they have not been successful. Has anyone ever heard or seen anything like this before? Have you seen it for sale anywhere? Perhaps you know what is is properly called and a quick internet search can help us find it. Any and all help would be appreciated!

Bree Barnett Dreyfuss
Amador Valley High School

FLIR's next generation smartphone thermal camera

The Consumer Electronics Show (CES2015) was recently held, and vendors were pushing their latest and greatest gizmos.

This includes FLIR, whose FLIR One thermal camera case for iPhone 5/5S was discussed in a previous post.

The biggest complaints about FLIR One was that it was limited to the previous-generation iPhone. People with an iPhone 6 or an Android were left out of the thermal imaging party.

FLIR aims to address these concerns with their next generation FLIR One model. It's not a case, but an attachment.

Next Generation FLIR One (CES2015)

Arcs over Amarillo: A sky full of halos

And my first attempt to embed a Facebook post and image URL. We'll see how it all goes.

"Yesterday morning, Texan Joshua Thomas took this picture in Red River, NM and shared it with us. He captured a truly special display of ice halo phenomena including rare suncave and sunvex Parry arcs, helic arcs, and intense supralateral and infralateral arcs. See also the diagramed version, which the outstanding folks at US National Weather Service La Crosse Wisconsin did for the photo. To learn more about ice halos and other atmospheric optical phenomena, see the Atmospheric Optics page: www.atoptics.co.uk. Thanks again to Joshua Thomas and NWS La Crosse for taking and documenting this halo display!"

Post by US National Weather Service Amarillo Texas.

New video questions—Cosmos: A Spacetime Odyssey

I've updated the "Cosmos in the Classroom" page to include question sets for episodes 1–12 of the Neil deGrasse Tyson-hosted Cosmos: A Spacetime Odyssey.

The Cosmos page still has all the question sets for Carl Sagan's Cosmos: A Personal Voyage. Those pages have been updated to include name, period, date info in their headers.

So now there are sets for episodes I-XII of Sagan's Cosmos and episodes 1-12 of Tyson's Cosmos. Each series has 13 episodes, but my intent is for students to watch those final episodes without question sets.

Cosmos in the Classroom

My own classroom practice is to follow each unit with an episode of Cosmos. (Sagan's in Physics and Tyson's in AP Physics 2.)

I'm disappointed that Sagan's Cosmos was been removed from streaming video at Netflix and Hulu in September, 2013. That prohibits me from using these lessons as "flipped classroom" assignments.

I own the DVD version of both "seasons" of Cosmos. But I've noticed differences in the episodes on DVD compared to the episodes that stream on Netflix. Some are trivial and insignificant. But one invalidated a question I wrote in an early draft of the Episode 4 question set.

I hope someone out there is cataloguing all the "disc vs. streaming" differences. I'm not even sure why they exist at all. But I haven't delved deeply into the issue, as so many other projects beckon.

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 

OK—break's over… kind of

I know it's been a while. And my output was off for 2014 compared to previous years.

The reduced output relates directly to berthing AP Physics 1 and AP Physics 2 at Rio while also retooling Physics from the California Content Standards version that I had polished for the past decade to the Next Generation Science Standards version that is expected to blossom in the next year or so.

So yeah, making this all happen at school to the best of my abilities keeps off the streets (and blogs) at night.

I have no idea when this will be completely sorted. It would be an error to presume that once the year is done, I'll have The Perfect Physics, AP 1, and AP 2 curricula all worked out and ready to repeat until retirement. But I also don't expect things to be as bad for me next year as they are this year.

I do have some groovy posts in the works. They'll be up soon! Neil deGrass Tyson's Cosmos and the Tavurvur volcano are topics.

But I must wave the "My Dear Machine" flag once again. I still love the song, and Leigh Nash's voice is dreamy.

Sixpence None The Richer - My Dear Machine

I am the pot of gold!

We've been getting some much-needed sky-water in Sacramento lately, and the forecast promises even more. California is literally collapsing as we pump out the ground water the state sits on, desperate for precious H2O.

Our reservoirs remain low and we're still in a drought, but we inched our way toward normal with some nice downpours today. As the heavy weather moved eastward, a break in the clouds allowed the setting sun to poke through. And there I was with my iPhone.

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.