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. The whole kit and kaboodle is available here (answer key included—that's the kaboodle).

Victoria Phyz Falls @ TPT.


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.