Sunday, September 28, 2008

61 Science Nobel Laureates endorse Obama

A group of 61 Nobel Laureates have gotten together to endorse Barack Obama for President. Their letter and the signatories are here. This is the largest number of Nobel Laureates to ever endorse a candidate for office.

Tip of the ballot to The Bad Astronomer.

Saturday, September 20, 2008

Book of Phyz updates: Force and Interaction

I've updated a couple of documents and presentations in The Book of Phyz unit on Force and Motion.

1. LabPrep: Carts and Tracks. An activity focused on learning the Pasco Introductory Dynamics System. The tracks and carts are nice, but students need to spend some time to get familiar with them. Since we do several IDS-based labs across our two-year sequence, it's time well spent. Document updated.

2. Lab: Going Through the Motions. This one is focused on understanding acceleration through Pasco's Visual Accelerometer and fan attachment with the IDS. Document and presentation updated.

3. Lab: Putting the Force Before the Cart. This activity develops Newton's second law using the IDS and Visual Accelerometer. Document and presentation updated.

All can be accessed here.

Sunday, September 14, 2008

PTSOS-Now also in Sacramento!

The popular and successful PTSOS New Teacher Workshops have expanded to Sacramento. I will be hosting Workshop 1: Mechanics ("Overcoming Inertia") at Rio Americano High School on Saturday, October 18. More importantly Steve Keith, longtime physics teacher at Casa Roble High School and Presidential Award for Excellence in Math and Science Teaching recipient, will be presenting as co-leader.

The PTSOS workshops at San Mateo High School continue with Paul Robinson and Dan Burns presiding.

Stephanie Finander continues as Reach Out Coordinator.

For more information on PTSOS and the workshops (and much, much more), see our website at You'll find information there on how to register for an upcoming workshop.

Inertia at high speed

The chronicles of high speed video as seen through my Casio EX-F1 continue. The latest episode focuses (!) on our Inertia in Action PhyzLab.

Click here to go to the full Inertia Video page.

A brief explanation of each activity.
Card Trick: Put a coin on a card and put the card on a cup. Remove the card in one swift move (without changing its orientation).

Hoop Dreams: Balance a marker pen on an embroidery hoop atop an air-core solenoid. (Some prefer hex nuts and wine bottles.) Next, remove the hoop so that the pen drops into the coil. There's a bonus video from 2002 showing a student attempting the difficult triple Hoop Dream.

Tablecloth Trick: We use physics textbooks in lieu of fine china. Then we try loose sheets of paper. The paper is non-trivial.

Click here for the full high speed video page.

The Flying Circus of Physics

The Flying Circus of Physics is a wonderful book of physics questions. Not number puzzles. Not problems. Questions. Questions drawn from observable, real-world phenomena. It is the product of physics professor and popularizer extraordinaire, Jearl Walker. I discovered the book early in my teaching career and have regarded it as an essential volume for physics teachers (and the physics curious). I present several of Walker's questions to my students as homework throughout our two-year sequence.

As light-hearted as the title might sound, the book is serious physics. "Naked-eye physics," as Walker describes it. In the 1990s, Jearl Walker did a thorough overhaul of my favorite calculus-based physics textbook, Fundamentals of Physics by Halliday and Resnick.

In the better late than never department, I see that Walker updated his treasure-trove in 2006. As with the first edition, it's available in several languages. Walker has also established a robust web presence around the second edition. He's even got merchandise! My T-shirt is ordered an on the way.

Check out Jearl Walker's Flying Circus of Physics. If you teach physics or possess curiosity about the world around you, you should not be without this book.

UPDATE: Oily snorkels! Full episodes of Jearl Walker's Emmy Award-winning Kinetic Karnival can be accessed from a MySpace page posted and maintained by his students. Once on the MySpace page, click "View my ... Videos."

1. Inappropriate

2. Ordered!

Tuesday, September 02, 2008

Physics in the Fountain of Fizz

The Mentos geyser became an Internet/YouTube phenom some time ago. Theories abound on the chemistry of the phenomenon. It seems the surface roughness and gum arabic of the Mentos are the critical elements.

If you've been living off-world for the past couple of years, take a moment to familiarize yourself with the Mentos geyser.

In the meantime, I developed a demonstration narrative to examine the physics of the Mentos geyser. Not the chemistry. Just the physics.

To examine the physics, measure the mass of the geyser ingredients before and after the eruption. This will allow you to calculate the mass of the fizz ejected in the eruption.

Measure the maximum height of the eruption and the length of the interval during which the eruption occurred. Doing so will allow calculations of the mass flow rate, the speed of the fizz as it erupts, and ultimately the power developed in the eruption.

The error bars on these calculations are significant. Estimations and simplifications dominate. But the fundamentals are there.

Where does this demo fit into the physics curriculum? I'm planning on using it at the end of my unit on energy.

Anyway, here's the sheet. Keep in mind this is version 1.0 of the sheet. I'm open to suggestions on how to improve it.

If you're looking for a slick way to get the Mentos into the soda without getting the soda onto you, check out the Geyser Tube from Steve Spangler Science.