Thursday, December 04, 2014

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.

Sunday, November 30, 2014

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.

Wednesday, November 26, 2014

Bungee Jump Physics Extravaganza!

I hate to overstate the case, but this activity is a whole lotta physics going on. Terms such as "Wow," and Bidenisms like "Literally over the top" come to mind.

In July, I jumped off a bridge. On purpose. In Africa.

A video was recorded.

Victoria Phyz Falls

Physics happened, and I was keen to exploit the event as an analytical assignment for my students. Because that's how I roll.

But such exploitation was not a trivial affair. I undertook the jump as a tourist about as far from home as I could be on the surface of the Earth. Deep in the midst of a month-long African wildlife photo safari detailed on The Treks of Phyz blog. Not as a physics teacher at a nearby amusement park loaded up with sensors and synchronized high-speed videography gear.

So hard data was limited. Easily measurable quantities on the captured video were limited. Quantitative information from the vendor proved… unreliable (See the "All the Facts" tab here).

What follows at the link below is a six-page student activity that could be assigned as homework or completed as a "video lab" in class. As always when working with a YouTube video, I recommend downloading ("ripping") the video first. As a Mac user, I then use QuickTime to trim and study the video.

A shorter YouTube Baird Bungee video can be found here.

The lesson engages issues including force and motion, Hooke's law, conservation of energy, and simple harmonic motion, among other things. There's qualitative analysis, verbal interpretation, graphing, direct measurement from video, and robust quantitative analysis.

In short—there is no "short": This thing is a beast.

I felt compelled to ask for a consult from Dan Burns, AP Physics C master teacher, YouTube sensation, general brainiac, and a maestro of mechanics. To suggest he is the Maxwell to my Faraday inflates my stature more than it does his. He was kind enough to give it a very thorough going-over. Many thanks, indeed, Dan!

Dan's analytical approach differed from mine, but we ended up with the same answers. And we both recognized some sticky issues incumbent in the quantitative analysis of such a data-poor problem.

But enough of my jibber-jabber. Allow me to present

Bungee Baird (PDF).

The answer key is available upon request to classroom instructors who send requests from their school email accounts. Kindly include "Bungee Baird Key" in your subject line.


Tuesday, November 25, 2014

Common Mythconceptions: a poster from Information is Beautiful

"The World's Most Contagious Falsehoods"

I paid the $5 to get the high-res version, and printed it out onto 22"x17 paper with my big Epson 3880 inkjet printer.

I posted it where students can see it from outside the classroom, and it's definitely got some flypaper attraction abilities.

Information is Beautiful's Common Mythconceptions

Some topics are intended for a more mature audience, so I don't recommend it for middle schools.

Sunday, November 16, 2014

FLIR One: A thermal imaging camera for your iPhone 5

The world is lousy with iPhone cases. They're available in all manner of designs to suite a wide variety of tastes and brand loyalties.

FLIR Systems has a $350 case for the iPhone 5/5S. It's a dual-camera thermal imaging system called FLIR One.

FLIR One is a battery case with two cameras whose lenses are in close proximity. One camera is sensitive to visible light, the other is sensitive to infrared light.When actuated, the two cameras collect images simultaneously. The FLIR One app processes the two images into one "thermograph" The app uses the visible light image to create outlines of hard edge boundaries of objects while the IR image is processed into false colors that fills the frame.


If I had an iPhone 5 or 5S, I'd be shooting the world with one of these things. I eagerly await a FLIR One for iPhone 6.

(FLIR is an acronym! Do you know what it stands for? I'll put the answer in the comments.)

Monday, November 10, 2014

Is inertia the truck driver's friend or foe?

The answer is: Yes!

First the classic. We love it, we know it, we rip it, we show it.

Shopping Cart Fail:

But inertia and Newton's First Law are not always your enemy. Some truck drivers make inertia their friend.

Taiwanese Bamboo Delivery

Tuesday, November 04, 2014

Groovy… but I won't show it in class

Except as a springboard to a discussion of "What did they do wrong this time?"

But it is groovy. The world's largest vacuum chamber is used to perform the a variation of age-old physics classic, "penny and feather" free fall experiment.

Brian Cox visits the world's biggest vacuum chamber - Human Universe: Episode 4 Preview - BBC Two

Here's a video clip that I do show in class: A hammer and a feather dropped on the Moon.

Feather & Hammer Drop on Moon

Brian Cox is many kinds of wonderful, but showing free fall in a vacuum chamber using high-speed (slow motion) video, alone, acts to deceive.

A common misconception among physics learners is that gravitational acceleration depends on atmospheric pressure. Things float in space because there's no air in space. There's no reason to think g in the giant vacuum chamber is 9.8 m/s2. All video of free fall in the evacuated chamber is artificially slowed. We never see the vacuum chamber free fall in real time.

The lesson could be interpreted that things fall more slowly in a vacuum. On Earth as it is in Heaven. Or the Moon, at least.

Sunday, October 26, 2014

And that's the week that was...

a strong contender for the craziest week at school in my 29 years thus far. I cannot divulge all the details here, and there's even more going on than what I'll document in this post. But even what's out there is enough.

It began Friday, October 17th with an impromptu student protest that I began hearing about through the student chatter between classes. News vans were on campus, media was being collected for news pieces later that day.

There had been an incident involving a student and an administrator. A physical altercation had occurred in the vice principal's office that involved the VP physically restraining the student. The student bit the administrator through the flesh. The students were protesting in support of the administrator-biter.

KXTV News10's slideshow:
Rio Americano students tape mouths shut in protest

At an optional, information staff meeting after school, we were informed about details of the protest and how it was handled by the principal. We also learned that some graffiti left in a girls' bathroom threatened a school shooting on October 22. October 22 was also the date of the school district's disciplinary hearing regarding the biting incident.

San Juan Unified School District's Threat Assessment Team was called into action, investigating the threat with the Sacramento Sheriff's Department. Eventually, the Federal Bureau of Investigations and the Department of Homeland Security were involved. Additional law enforcement personnel were brought on campus and teachers were asked to be out and about during prep periods.

By Tuesday, October 21, a note had been found suggesting the shooting had been bumped up to that day. There was apparently some absenteeism beyond what should be expected. The drumbeat of local news coverage served to amplify the drama.

Here's KCRA's contribution (Sadly, this reporter didn't really know where she was. "Rio Americana"? Really?): Rio Americano HS attendance drops after shooting threat"

And this from The Sacramento Bee: Rio Americano shooting threat leaves students, parents nervous

Not surprisingly, absenteeism was decidedly more pronounced on Wednesday, October 22. I went about my business as per usual. Teaching physics, as I do. With heightened awareness, but not with anything resembling a siege mentality.

Things were going smoothly until lunch. About ten minutes into lunch, the fire alarm klaxons and strobes began to fire. I presumed a student sympathetic to the biter was looking to make a splash on this day. Still though, the entire school population was mandated to proceed away from all shelter and out into the sniper-friendly open areas of campus on the day a school shooting was threatened.

The genesis of the alarm was not as I suspected. No, it was merely a colleague burning microwave popcorn during lunch on this—of all—days. One hopes he learned the importance of staying with the machine while the corn is popping. But I doubt it. His subsequent blog post is less an apologetic mea culpa and more a Nixonian, "You won't have me to kick around anymore"/"I'm taking my ball and going home" vibe.  This from someone fond of publicly referring to people of all walks as "idiots" and publicly calling others out for "incompetence". (I set off the school's fire alarm once, too. Here's my post on the matter.)

Clearing the alarm pushed lunch later, so our 6th period block period lost about 15 minutes of instructional time.

And on Thursday, some of the faculty officially played softball after school. [Rio's greatest video coming soon!]

On Friday, a local, tragic crime spree sent ripples throughout Sacramento and beyond. With police helicopters circling above, our principal came over the PA (for the third time this week) to announce that the overhead activity was not related to anything at Rio, but that we were now sheltering in place until further notice.

The shelter in place continued into lunch until 12:30pm. By then, I had volunteered to escort classes of students to-from the bathroom per shelter in place protocol. A group of parents had hoped to have a donut-filled celebration at lunch to mark the passing of the stressful week. With lunch being forestalled, donuts were shuttled to sheltering classrooms. The events that precipitated the shelter in place at dozens of schools made national news.

With nerves sufficiently rattled school-wide and many minutes lost—this time from the afternoon classes, I moved tests scheduled for the afternoon (AP Physics 1 and AP Physics 2) to Monday. On-the-spot lesson-shuffling was implemented so that minimal instructional time was lost.

My take?

Through it all, the school's administration handled things with calm aplomb and laudable professionalism. This in the face of what appear to be the aberrant claims of a misbehaving student and her mother, a misguided student protest, vulturing local news media, and other obstacles. Based on what I know, I have no reason to suspect that the administrator involved will be found at fault of any misconduct whatsoever.

I hope none of my colleague's stayed away from school October 22. I was disappointed that so many students did. An abundance of law enforcement was brought to bear on the situation, and they did not find the threat to be credible. Keeping students away from school that day allowed the graffiti-author to have a disproportionate disrupting effect. Running in fear from every emotional outburst generated by teenagers in a high-school community gives undue power to individuals who clearly should not have it.

Ad infinita:
rio americano tumblr
Principal's Message 10/24/14

Sunday, October 19, 2014

Captain Disillusion - Viral Videos

Captain Disillusion gets his Cosmos (NdT version) on, with nice references to his previous Tumba debunk, outlawed magnetic Buckyballs, and magnet boys.

Captain Disillusion - Viral Comets Truck Saves Plane

"The Laws of Attraction" — A new PhET sim-based lab

This activity is a fairly deep exploration of the elements of Newton's Universal Gravitation. In the "Gravity Force Lab" sim, the force between two masses is displayed. Both masses can be changed, as can the distance between them. Mathematical patterns are developed and cobbled together until the full universal gravitation proportionality is constructed.

My lab activity, "The Laws of Attraction" can be found here.

PhET's "Gravity Force Lab" sim can be found here.

Here's the sim as it can be embedded:

Gravity Force Lab
Click to Run